·hin Noku 4
AMERICAN LECTURE SERIES
A Naprapt
AAIERICAN LECTURES IN LIVING CHEASTRY
Edited by
1 NCITOV KUGELLASS, V.DPD SD
Coorleat to the Departmend of Health and Hoqlab
Alark,
nork

·MOLD- THE CHEMISTRY OF HEREDITY By MENH STEP DEN Php Associate Profew of Brocbometry Dupont of Blachondatry Coboch Uanystry Categy of Physicots and Surrou Nro York Noo York BLACKT FLL SCIENTIFIC PUBLICATIONS OTPORD ·This book is copyright. It may not be reproduced by my berns to whole or be part mah tp al n. Appllant ith rot od to copyright should be addrodd to the publisher Published and copyntebied IHI A the Used Steamerican CHARLES C THOMAS PUBLISHER 301 377 Lot Lovrence Aretus Sprtogfield, Mood Publisbed santney a Cash THE RYERSON PRESS Queen Street West, Tardoto 2 Med thy Used Santo ART ·This book is dod loated to the enligttonod programs of research groats la our country retour support made possible mod of the recent discoveries la the field of the chemistry of korodilly

·No text on this page.

·INTRODUCTION The very thought of reading a book about the Cberinstry of Heredity u likely to encounter a great deal of renstance The word "Charrustry often inmcal uad reminds one of a lot of difficult or boong moments in ode school day And why study heredity at all? It s with me, like the weathcr and nothing can be done about it. Well, pertezps something can be done about it. And chemistry of properly seasoned, need not be impalatable. And perhaps the whole subject affects the progress of medicine more than one thought The fint reason to study the chemistry of heredity is plan curionty here is an important natural mechanism and ro brule o known about it. Especially after the second world wu thus thongtit became to tinting and humiliat jag to banc screntes that they decided to pursue the field and comparavely swift progress has been actieved ales, the field even became fashionable. But the problem of the chemistry of heredity also hus most important practical applications, for the practitioner s well as for the researcher Lets look into these appuca ILOILL L HULLAN HEREDITY A number of diseases or defects of previously known ongin, have been fonod to be hereditary This number 10- creures rapidly o the family records of cores are being audied. In a few imances to be discussed later) the bio ·yul THE CHEMISTRY OF HEREDM chanical defect underlying the disease has been well traced ottien all remain 2 challenge to the researcher bat if the disease is known to be hereditary thert s a good chance of mapping the reactions involved and trapping thic defect, usually as a block in an enzymatic sy#em. Once the biochenistry of the defect is known, an intelligent treatment can be (and has been) proposed A related field is that of the hereditary susceptibilita to descase. Of these, the problem of hereditary susceptibil ity to winous types of cancer holds at present a great deal of interest. While the statistical studies in human popola tions did not result yet in a unanimous opinion on this subject, there is absolutely no doubt that in laboratory imals (mice) the suscepability to some types of cancer can be hereditary The chemical basis of this hereditary defect is as yet completely unknown, the problem may have to wut for the progress in the understanding of cancer in general II. CANCER The problem of cancer appears to be closely connected with that of the chemotry of heredity in the front fly (Drosopbila) and in certun fisties come foms of ancer arc hereditary The genes for it have been located in the chromosomes, 17 e ару other genes, and there i no reason why they should not follow the general make up of the suggests that the cudy of the chemistry of tbe gone is not without interest One of the respected hypotheses of the ongin of some types of cancer (also in many suggests that the cancerous cell occurs o a mutint of a pouztic cell if so then the cberastry of mutation too is of considerable interest. Another hypothesis indicates that a virus may be a causa are agent jo some types of cancer As it will be shown subsequently the infective agent of the virus (the "gene" of gene. This alone ·INTRODUCTION DI the virus) is a chernial substzace closely reared to die Abstance of the gone of the host, the materiction of the two biochemical systems Bagun 20 muportant problem in the field of chemistry of heredity Finally the mode of action of some cranogenic agents, the claadaaon of the upsetting of brochemical processes m the cancerous cell, the modern chemotherapy of cancer based on inhibition of syntheos of genetical matenal of cancerous cells, are all problems in the field of chemical genetiek TIL PATHOGENIC BICROORGANISAS If the problem of infectious diseases crused by bacteria md other fungi appen to us ka memang than it did to the previous generation, it s only becruise temporarily thanks to antibioaas, we have goned the opper hand in the fight igainst these microorganisms. As we know the microor gannus fight back, by mutating to #runs restent to antibiotics so that new anobiotics have to be constudy ducovered. What if we slow down, or work will, reach the bottom of the barrel The study of mutations of microorganisms to antibrouc rowstance as one of the subjects in the rapidly capanding field of research, metobud genetics The chemary of the geoc o general, and of mutation in particular the time genetic material from one cell to mother art agun at the base of all the problems in this field. The chemical substances anymg the heredity of the tuses have been citricted and are open to chemical Rudy Thus gudy has aggereed ways of how to interfere with the noml proces of synthesis of these substances o o tom hibit the molaplication of the vims. The mportant prob lan of mutation of virus to the struns which are more virulent (epidemiology) or which are attenuated (for vac son of ·X THE CIEVILSTRY OF HEDITT cina) is also essentially a problem in the chemistry of ma toons. Recently the study of the chemistry of the viral "genes" has led to the laboratory production of viruses with known chemical changes in their gency, thus viruses which nerer ansted in nature have been obtained, a de velopment of as yet unpredictable consequences. The raped progress m the field of the chemistry of the genes has been graatly helped by the fact that the chemical basis of the genes is essentially amilar in all living enaden down to the amplest viruses. This obligmg arcu instance allows the biochemist to work with genes of convenient, fast mulaplying organions such as bactena, and yet draw valid conclusions concerning the chemistry of human genes. Onc us tempted to speculate that thus us because these chemical substances (or the prototypes) determining the heredity must have been the first heralds of life, indeed one cannot visualze a living enary which would not carry 10 own heredity Thus, of all the perpleung systems, the one concerned with genetics is considered (by the geneticasos) the most cssential for the definition of lfc.

·CONTENTS
Pagr
Chapter
LYTRODUCTIOY
Tui
LMHANDAU or HADITY
3
IL Hammy DETUTINANTI AS CHEMICAL SUNSTANCES
8
ID THE NUCLEIC ACUS
6
I MIUTATIOY
48
INTEMPLAXY SYSTEM AND CYTOPLANTIC
INHERITANCI
59
VI THL ParsuL REACTIONS
65
VIL HOTARY DOTS LY MAN
75
ATOLOGY
81
BILOGRAPHY
BS
Subject INDI
101

·No text on this page.

·THE CHEMISTRY OF HEREDITY

·No text on this page.

·Chapter 1 MECHANISMS OF HEREDITY If we were added to dengo, on broad terms, a complete mechanen for the ordkdy transmission of human heredity by bang ample logic, how would we go about it Perhaps at first we would make sure that we bave a way of registering the information for determoing how the nert human generation would be like. We would want to be sure that much mormanon u never lost thus, whatever vehicle we choose for carrying this information, it would have to be a stable one. After all, it takes may thousands of yours to accumulate the biological crperience of the race ud it s a very pamful process, mvolving the clumnation of the less fit we would not want to lose thus experience in a moment just because the informmon curier wus unreliable. Thus, the first centual elements in our deagn would be counc rather cable, transmissible information me, wbuch & Vinzou times have been called genes, genetic de terminant or heredity determinants. The name "deter munan" oplies that the Thing B not merely pasive but Actually determine what the next generation will look like It is not enough for the heredity determinant to be passed to the next gericnipon (through the fertiled egg) for there are a great many cell divisions between the age The me my oto deset thing to dufam bo, borever ce de tern Auced in the limit, nl be used to this book oda by ode the better define te bereity deren ·4 THE CHEVESTY OF HEREDIT and che mature indidual and every one 1 cell dirides, the heredity deterounants would get diluted twofold, vool practically none would be present in the cells of a mature individul So if we want the information to be passed un diluted and mchanged to one more generiaon, we should make sure that our heredity determinant knou hon to du plicate themselves (replicare) unchangede preferably citry come a cell divides this way they will always be present undiluted at 1 moment s notice Thus, the heredits determinants are the first system whuch we necd. Bar this, of course, is not sufficent Ilc know that the genes determine everythung in the organison the blue color of the cyes as well as the milk scretion But we would not want the genes themselves to have pigment or to secrete milk. IVhat we need, then, s an intermediary mechanism which carries the orders from the genes to the are of execution of the ordern, that is the final chemical reactions. These reactions may take place anywhere in the cell, sometimes even on the outer surface of the cell membranc surely it would not be safe for the cells to keep chere their most valuable records, the genes. Our dengn would be winter of the genes were locured in some volt buried deep within the cell, ach is the nucleus. But that of course, will necesitate the mtermediary mechanisn we just mentioned To relac hos much soch a mechanism needed, one may recall that in some cells, notably motor neurones, the пр of the aron, a here some gene-controlled reactions anle place, may be four feet away from the nucleus! We do not koo much that to requare of such an intermediary mechanism se ure nou designing but one thing ut do know me trant chus mechanism to be practically weidirections lle allos changes in the genes to be transmitted to the final chemical reactions ochorarse there ·ECHAXZUILS OF HEZDITY 5 would be no a olotion. But we do not mint the changes in the final chamal ractions to be transmitted back to the ganes, because these chemical reactions M, be influenced by the CNTIODICAL, and so changes. To give an cumple e mechacal mjury to the goods may upset many of cell olar reactions, sili we wzot the genes to reomm unchanged so that our children be born without injury to their gomads. Thus, then, as the second system which we need the Lotermediary mechanism. Finally the churd system requred would be the final gene-controlled chemical reactions of the cell, which we may call the perspberal reactions This sbould be a very lotnicate system, including practically all that s going on in the cell, bechese probably nothung can go od wrthout an active or slent approval of the genes. If we now examine the mechanisms of heredity actually Casting in mature, we will find that they correspond rather well to what we have dengned m general terins using an ple logic. Our present knowledge of each of these stems leres very much to be deared, in fact, we uc just enter mg the vestibule of infinity Nevertheless, these three syy tems are very real, es illustrated bnefly by the following cumpla. There B a abstance, alled transforming procple, wuch somehow am aurty the genetic mformation from one bacterial cell to another Alore will be mad about this substance in the next chapter here it suffices to mention that the chenal mature of the substance is well known and that the substance au perform a role (carrying the genetic information) all by itself without any neciety of Accesory substances. To be sure, we do not know that the substance en determae heredity unol the substance has fouod 10 Fry into the living cell but this is not para mount. the main point is that the substance can be ertrict 117ich boa part de ·6 THE CHEMISTRY OF HEREDITY od uonjured, panfied and thus separated from all the other Systems, and that this separation does not change the quality or quanaty of the genetic information The B, then, 20 cumple of an independent mechanisin which we have alled the fire system, the heredity, determinants, An interesting crample of the second, or intermedury System, which ames the orders of the genes through the cell, is furnished by an alge, Acetabularia The organism looks like a slender mushroon about one inch high, with: rootiet and a shank, on further cularation, a small green aps formed on top of the shanl Thos alge os interesting because it comes of a angle cell and has a angle arcleus Domy Anated m the rootlet Supporme non that we cut off the nucleus carrying rootlet of e young alga u hich has not yet developed the cap One could think that once the nucleus with the genes in it has been removed, the plant will not know how to make the cap once the shape and the color of the cap mo be gene-determined. Yet the alga does know and makes itself a perfect green cap in fact, for at least two w cels ofrer cutting the synthesis of protein proceeds at the undoninished rate Ithere was the gener ic information? It is believed that it has been parsed from the nudeur genes to the information-coming stond system co the cytoplasm this system can now perform, inde pendently from the fire setem (heredity determinants) a hich has been literally cut off The separate third synon aos actually the earliest one to dret utenaon of biochemsus m fact for many years the espresoon chemical genetics" meant only a branch of gencias concerned with the effects of mutations on the penipheral reactions. This smem s also the anat to separate from the others. The gene-controlled final reactions in the cell are usually enzymatic reactions, the enzymes an be cancted from the cell punified and often even crystal- ·MECHANISMS OF JETTEDITY 7 used in genetics lized they can be made to work in vitro on their appro prate substances, which are ather citracted from the cell or syntheoned in the Laboratory the conditions cresting in the cell (pH temperature) can also be imated Thus the entire peripheral czymatic reaction can often be re-cre ated in the test tube, even though the heredity determinants and the information carrying systers are no longer there. It may be useful to correlate the brochenmaal concept of the three systems with the terms genotype" and pheno type The genotype is the genetic make up clearly the chanical bams of it is the fire system (heredity determinants) The phenotype u the physical makeup the way the nodividual looks. But the way dividual loolas depends on what we like to look at. The color of die eve is obviously a phenotype. But the chemist prefers to look at the chemical aructure of the paginient this phenotype, too So s the appearance of the dirombo 200, and even the chemical structure of the gene for aldough an individual getic meas the law for the cell, 10 chemial Aructure must also obey the lawı dictated by all the other genes. Thus, the phenotype of 10 individual us the end product of the collaboration of all three systems with the cuvironment the in- ·Chapter II HEREDITI DETERBINANTS AS CHEDIICAL SUBSTANCES Is but stubrps des mu platters # tup t• * to distrib he esterial from the tri In the previous chapter a menoon was made, nachoat any proof that a chemical substance can serve & the heredity determinant Such proposaon o not obvious at all, md therefore in this chapter an efidence will be presented to support the idea The thought that one s genes were to superior because of a mere substance, his likely to be unpopular for a long time. Students of the higory of science cannot fail to notice how often the issues most essental for our spead were cononuously avoided. Thus, m general the science of heredity which affects us more than astronomy was prac acally none stent until the second half of the mineteenth centnn aldrough Vendeis conclusons (1866) were ac really much easer to amre u and to accept than those of Copernicus (1530) or of Haryty (1628) 's late 1872 Spencer writes "Il care obliged to confess that Life mits essence cannot be concen ed in physico-chemical terms." By the end of the first half of this century the founda nons for che explanation of se ral biological phenom ena had already been lid Houeter the phenomenon of herediti u is not attractive to a chemist, perhaps because of 1 fear of the ulatude of substances mrolved and their in 8 ·HELEDITY DETERMINANTS AJ CHEMICAL SUNSTANCES 9 surmountable complexity indeed in contrast to simpler biochemical functions, nochmg less than the whole argen KIL, the whole cell or at least the whole churomotomal ap paratus semed indepenuble es beredity determinant The remains of the nebuloos arutude sull hamper research on the chemiary of heredity in a certam part of Eastern Eoropc Bot even after the acceprance of the hypothetical concept of a unit of heredity the gene, it was will not clear whether auch a concept had a physeal reality and even if the gene was real presumably it could be somethmg other than a substance. True, the chemal abxances are at the base of all livmg matter but the substances or such are not the only things which can cury information Conader for 1 moinent a charcoal sketch the information that the artist s trying to convey to w is not in the mature of charcoal particles. The particles are all abike but what is ppeafic and informatou-carrying is their specific distribution on the paper Now one knew for a long time that the chronosomes are souchow involved in the orderly transaktion of heredity it was therefore natural to think that it is the or guazation of the chromosoms, the speafic distributon of unspcafic, anugteremag nolecules that is responsible for determusing the heredity Such an hypotheus was indeed proposed It was simlated by the discovery of a phenomenon alled the pon tion effect (for i review c) the action of comc genes proved to depend, to some extent on thar portion among the neighbonng genes. For example, in the fruit fly Drosopbila, chronocomal region may become nuverted, or it may become transplanted (traslocated) into another place in the chromosomes, such alteracions may result in e change in gene scoon. However it has been found that this effect by no means univeal, even in Drosopbila' This alone would spend against the concept of the position or doen ·10 THE CHENILTRY OF FLEREDITY bution as bang the universal bags of heredity determina uon. Actually the posoon effect an be explained as well by the hypothesis that the informations canned by chemical molecules provided that there is some kind of inter action between them a digurbance in the interaction may result in a change in action. Indeed, some son of interac con or linkage between the information-carrying mole culos in a chromosome has been recently reported But the more decinec blow against the hypotheses that the enare information due to distribution of uninteresting molecules, was delivered by the discovery of the ring forming phenomenon. In this phenomenon the individual molecules were extracted from the chromoso, their spc cific distribution ou completely destroyed ance they were independendy moving in the solution, and yet they full carried unchanged genetic information therefore, the molecules themselves must have been interesting But let us first describe the transfomong phenomenon from the very beginning it is worthwhile to spend some one on this de velopment ance it represent a major breal through in biological thoughts of our century In 1928 Gnffith reported that when mice were inject ed with living non-encapsulated (R) pneumococti mixed with beat Lilled encapsulated (S) ones, living 5 pneumococci were recorcred from the animals. Of particular mtcrest was the fact that the specific type of the Scells 125 the mess the type of the heat-balled cells rather than the type from which the living R cells were denved (by some previous mutation to the loss of capsule) Once the neu fature (production of the capsule of a speafic type) was established, it pus retuned and reproduced in subsequent generations us if a neus gere had been added to the genet ic makeup of the receptor celb, indeed, such trandomised cells, when heat küled, could now serve to induce the ·FERIDITY DETELINANTS AS CHEALCAL SULTA\CE II to the trunsformation of R cell cactly in the same way us did the onginal S cells Although this experiment was confirmed by other work €12, it did not atract doc urmation, despite careful controls it will appeared possible that the seemingly heat-billed preparation contracd some heat resistant bacterul farms so that the phenomenon w i revival of the S cells rather than the transfomacon of the R cells. The poasibility of a boat restant was also was not excluded. Lo 1931 Dawson and Sus" reported that transformation aan ulso be dannonistrited otro These workers realized that the phenomenon affects only one out of тапу R cells and that it necessary to depress the growth of thus stram to give the few newly formed S cells a chance to mulaply point of recognition. They therefore performed the copermyrit in the presence of an ant-R srum, today this method is full che preferred one when transformang the R cells into S cells Alloway was first to demonstrate that the presence of the whole donor" (S) cells us not occerwary for the phe nonneron thus investigator prepared all free aqueous CI Tacts of the best talled S cells, passed the extract through bacenal filter and demonstrated that the filtrate u will apable of transforming the R cells into S cells. While thus cupermeat excluded the presence of a non-filterable bac terul forn, it did not exdude the filterable virus as the responsible agent, the crperiment was merely suggestive that the agent A water-soluble In 1944, Avery AlacLeod and AlcCarthy' purified the Curact further and found that the responsible agent (the turforming prnaple") has all the properties of a hughly polymerized deorypentose nuclec iad (DNA) this angle finding laid the foundation for the gudy of the transforming prinaple.

·THE CHEMISTRY OF HER EDITY The post un penod wytressed several important contn budons to our knowledge of the phenomenon and io mimi fications. Besides pneumococcus, the transformation has been accomplished m Hemhopbilus mfluenzse (Alexander und Lady 1950) these two bacterial speaa have since served as dependable tools for studying the transformmg phenoncnon uno and the behavior of the transformung proaple m vltro The phenomenon has been also reported in many other bacteru (for two recent reviews sc' ) It was ako found that the feature trinsferred (induced) in the transforming phenomenon is not limted to the produc bon of capsular abstences. Other transferable features include induction of fermentation of salıcın, change m me tabolism of glucose and lactic acid, production of mannitol phosphate dehydrogenase, prodaction of xveral speafic enzymes in the brosynthetic pattiway of tryptophane Uronc iad Sall other features inclade the change in thc gurntity of polymechande produced m this case it was suggested that the genes involved for 1 Knie analogous to what is known in higher organisms as an aletic enes. Sull other crosferable features, fine reported by Hotch- List include the change from senetinity to resistance to penicillin, pulfanilamide, streptomyan, erythromyan etcon and even a reverse change, from resgance to sendvity The class of transformation phenomena ss of particular in terest because it involves grodations (one-step or mula sep 1cquation of regstance) which resemble closely the gradations acquired by a matun process, that s by sponta ar ncous mutation. Sonne scientists feel that, if giyen enough effort, prob ably every feature could be shown to be transferable, and dac olunately the emare bactenal beredity r]] be oc counted for by the extractable substance, namely DWA Other sacntists are more aurows perhaps there are some ·HERIDITY DETELMINANTI A CHEMICAL SUBSTANCES 13 heredity futures carried by another substance? The evi dence that some features indeed are determined by some chung on the cytoplasen (though still under ultimate control of the nuclear gene) will be given in Chapter V when we will disctu so alled cytoplasmc inheritance. However tha aurilory mhentance seems to be nether escrita por independent, ad nowadays saventists to general agree that DNA s the only substance wluch enjoys the evidence for carrying the main" heredity of the bacterul cell As intimated above, when one looks at the results of transformadon (acquiaon of a capaile or acquisition of . raestance to antibiotics) one camot help noticing their great anunty to ordinary mutation. Yet the mechanism of the two procesus secins to be different in trupafarma non we add a new molecule of heredity determunant, in mutation we cage the existing one. Not all the stent agree with the view come feel thar ance we do not know cnnctly what happens in the cell, we cannot adade the posuiburty that the entering molecule of DNA does not idd itself but merely changes the existing molecules, as poonally at the time of their replication Whatever the details of the phenomenon, the possibility of worting with the hrtherto unalable material of the cellalar nucleus is of grat mportance the violation of the Atomic nucleus by the physicists was louder but in a long run the tinkermg with the genes may be of more conxe quence. As a moden beginning one can already amat from the donor” bacternal cells the heredity-crying DNA, punfy it like any other chancal sabatnice, audy Its phytal and chemical properties, subject it in the to tube to physical and chemical agents, and then introduce If into the receptor cell where it will will work and deter mirc the heredity of this cell, like any other genc (for two Itctnt reviews ) ·TIJE CE55723 OF REDDY Ihile this was going on in the field of bacteriology the samusts began to look for amilar evidence in other liting enata. Vinses, being ampler dien bactent, secured od mirable matenal and attracted moch attention from basic scientist In 1951 Lederberg and Zinder noticed that when Salmonella cells with certain hereditary murs are lysed especually by weathly lyric bacteriophages (bacterial viruses) the lveate contains a filterable agent apable of inducmg these trees in other Salmonella cells the phenomenon has been given the name crosduction! The cause of the phenomenon ut etentually foumd to be associated with a bacteriophage presumably serving 13 1 carrier for the material which changes the beredity of the host (receptor) cells. The nature of this phenomenon is rall not clear If thic hereditary material transferred sa cherucal substance (DNA) then the phenomenon an be called a special case of transformation (or vice vera) how ever if the transferred material sa bactenal chromosome or 105 part then the phenomenon onay be of different na tort. Vlorcover for this study it should be greated thar the hereditary materal, when ourde of the cell, wecus to be completely prorected the indicates that the phenomenon does not lend woelf to phyoco-chemical study of the ma teral metro For the reason the phenomenon, though undoubtedly very interesting will not be discussed further in this book Vlore insght into the chemical nature of the genes of viruses was furnished by the asperiment of Hershey and Chase' These inrestigators grew bactenophage in bactens in the presence of radioactit sulfur end radioactive phosphorus. Sulfur o present in certain amino acds, therefore, the viral protan haring these utudo aads became labelled with radioactivity On the other hand, phosphorus s prot- ·HODITY DETERMINANT) AS CHEALICAL SUBSTANCES IS ent in the nuclac iads and in this way the latter becue Labelled with radioactivity Nan kep was to infect the hose cells with such doubly labelled phage and then to search for the presence of radioactive sulfur or phosphions within the bacteria. if only the redioactive phosphorus were there, it would mean that only the nodec nad of the phage pene trated into the host cell if only oolfur it would mean that only the proteins ded. The result was that practically only tbc phosphorus was radioactivs, darly indicating that the mfcction meant the passage of essentially only nuclec nad of the phage moto the host cell In addition, ance the only nuclac aad foood in phage is DNA, the conclusion is that the DNA alone is the infective material of the phage. Thus conduson, now widely accepted, was another important development in our understanding of the chematy of heredity It must be noted that thus for the attempts to infect the host cell with DNA alone have been unsuccessful the proteins are still needed, as auxlary pubstances for infection though they do not determine heredity However the work in this field is progressing a recent study has shown that if onc removes the cell wall from the bacterul host cell (forining a walked protopless") then the cell om becouse infected with a pluge wuch as so injured us to be COTIK 1 balf way form between pure DNA md the intact virt. As will be discussed below the prekuce of DVA s in general a caracter of larger virties many waller one conton RNA us the only oncleic aad. Among those aud red curly were the plant viruses, first obtuned in cryxullme form by Wendell i Stanley The cheveuxit, for whurch Sanley received a Nobel Prize in 1976 had t most The price of protein, recompenyo the DA is yourncy into the cell, belicted to many actory role ·THE CHEMISTRY OF HEREDITY 15 14 While dus rus going on in the field of bactenology the scientists began to look for atmilar evidence in other lining entides. Virues being ompler than bacterie, seemned ad mirable material and attracted much attention from basic facts. In 1951 Lederberg and Zinder noticed that when Sal monella cells with certain hereditary truo are lysed, o pecually by weakly lyoc bacteriophages (bacterial viruses) the lysate contains a filterablc agent capable of inducing these two in other Salmonella cells the phenomenon has been given the name transduction The cause of the phenomenon is eventually found to be associated with a bacteriophage presumably krving as a carrier for the matenal which changes the heredity of the host (receptor) cells. The nature of dus phenomenon 4 sull not clear If chic herediary material transferred u a cheroical substance (DNA) then the phenomenon can be alled a special case of transformation (or vice Pern) hou crer of the transferred material es bacterial chromosome or its part theo the phenomenon may be of a different na tore Moreover for thus study it should be pressed that the hereditary material when ouode of the cell, rectX to be completely protected this indicates that the phenomenon does not lend 10self to physico-chemical study of the ma cerul m uttro For this reason, the phenometion, though undoubtedly very interesting will not be discussed further in this book Vore innght into the chemical nature of the genes of virtuses uus furnished by the experiment of Hershey and Chase These jorestigaton grew Lucenophage in bac in the presence of radioactive sulfur and radioactic phosphonu. Sulfur 8 prexnt in certain amno sads therefors, the viral proteins having these amino aads because labelled with radioactive On the other hand, phosphonu s pres.

·HEREDITT DETELVIYTI AS CHE.VIICAL JURTANCES 17 Two by brid" niruses resulted NAPs aod MP, where unds for mclac ead, and R-for protan. The problem was not which of the no posiposkats will the brand obey upon reproduction? Will st Fallon the nuclac iad (NAPa to become MAPA and IPA co become NaP) or the protein (NAPs to become N Pa and NAP'A to become PA)? The sister wu unequivocal the hybrid always followed the nuclec acid component, the protan er material for the determinator of heredisy Thus, the nu dec sada proved once more to be the sole carrets of Bet information Were the pacleic acids alone mufficient for infcction The querion was lowered by the godies of Glerer and Schramon" und Fracalel-Connor Gterer and Schrum mer of separating the nucleic sad and the proteis were much that the protan became destroyed m the process thes appeared unfortunate once they could not recoarome the rivo components as described above As it often happens in SOCKS, the unfortunate prostor proved to be trick for when seaed on a plante the nocłac sad alone proved to be infectare! Erache-Connst reexasuned his two separated component and found that while the pro ten was indeed completely Bon mfocare, che nodec and had some infectoviny Sunley goes as far as to my chat the nuclac tad ss the VW. To bx murs, the complete virus a more infecare than nociac aad alone but the scenes feel that the role of proteins in improving the infectivity us merely accessory pertuaps they serve as a prsects and against the eyma u arching the nucle and, or perhaps they product an - provement in us attachment but fir berediti concerted, the nucleic acid is all that u nectury edient t scienast were now nterested in finding . amuur beha tor for anomal n nusa The speed ( deel 22tt ·18 THE CHEMISTRY OF HEREDITY oporeads in this field was indeed remarkabla mdicung that at last the weight of purch discotenes uns falli releed Ilithin tuo years, the infectants of ribonucleic iad from Ilongo and Il est Nilc encephalins virus (from Ehrlich asaitas rumor cells) polo rind and Easter equincentcephalomyelitis virus reported. The finding of the 10- fecurity of the polio virus RNA is of particular interest The infccnon with such RNA an nou be accomplished in nogle layers of human cells in tissue culture The infected cells foron dead spots (plaques) if the RNA s destroveu by the enzyme nbonuclease, there is no infection and the plaques arc nor formed (Figure :) All these findings are for us to predict future development but un doubtedly they will put our knowledge of the correspond ing diseases on a neu logical level In particular the recog nition that the infecare agents arc nudac and should help w to design safe raccano in which the infecure agent K destroyed as will be mentioned further in, our knoni too ICH Fo. I Dead qoo (plata) poluced in the barcoti ronacles (RVA) of the pollo in on the neck layers of romance in LAX colture. Lotuth RII moto-RlA destroyed by myme mboga cente (Cartery D I Torpan Vlauntam ) ·cdge of HEREDITY DETERINANTI A CHEMICAL SUISTANCES 19 agents capable of dextroymg the soclde aads us by now quite axtalave. La summary then, the herediry datesmants of certum (usually malicr) virs are ribonuclac acids, while those of larger viruses (bacteroplages) and of bacteru deory nibonuclac ads. What about higher organisins, especially min lo all honesty it must be adoutted night at the start that our evidence about the substance determining heredity in higher organisms 8 Dot 3 convincing as it is for viruses and bacteria Transformation in higher organisins has not yet been proved though several laboratones are attetaping to do it One guesses that the story must be gmilar because so many brac processes are amilar m all living things, one has som trdirect evidence that it sound one has patience. Let us look, however it the indirect cridence. The chromosomes, long recognized as the most essential part of the apparatus for the orderly tranunoon of beredity show the presence of a large mount of nucleoprotein, in this compound, the nucleic lad o of the deoxyribose type (DNA) (for a review ke ) The spromatozoon, which aunas the core heredity information the malc as ever go mg to trumt to the nert generation, consists of over yo percent of nuclcoprotein (on a dry bags) in it, the DNA content can be us much as 2/3 of the total. The graules or bands of granules in the chromosomes wfuch can be seen in mny cells, most destinctly in the giant chromosomes of the salivary gland of the fru Ay Drosopbula (Figure 1) Corset agan of nacleoproren of the de oryribose type. These graules or bands, demonstrablc by the use of base dyes or ultraviolet light, have been known to be usocated with the steal gede loc. if the gene According to confirmed report it has been accomplished o ducha

·20
THE CHCVOSTI OF HEREDITY
܀
!
to set it
FK 2. Great Chrome of the linky pland of the frog ty Drasan
phil molotooth The con-benda contin corriborrockoprordin.

·HUDY DETENNANTS CHEATICAL SUBSTANCIS 11 changes 10 pontion, so does the corresponding band. Au there observadons suggest that here, too, the nucleoprotein playı ı very important role in the determination of beredtty But after these observadons the unanswered question re mons: what are the information the process, the nucac mad or the speafic way the two are combined? Some insught mto the problem can be gamed by the analyss of these componente it has been found that the compostion of DNA from spartinatazoa the manne as that from the chromosomes of somatic cells of the same species (for a review sec ) In contrast to this, the comportion of proten may change drastically in the chromosomes of sper matazom the proteins i protmme whareu m the corte ponding chromosomes of crythrocytes it is a bistone i pro ten of 1 very different compondon The replacement of huone by protumine appears to occur danng en advanced spermatogenees One instinctively feels that the substance which does not change (DNA) 2 more reliablc heredity amer than the 071c (protan) which changes so draually during the development for the same reason the bond between the DNA and the protein would not be a reliable regaster of the genetic mfarmacon But in moncave feeling a one thing and the scent fic proof is sorticthing else agun In 1949, Vendrely and Vendrely and aubsequendy Alurky and Rus found that the ONOME of DNA per (diploid) cell as the same in all organs of the more species (Table I) in haploid cell (that is the cell with only one met of chromosoma) ruch o spermatozoon, thus amount is fully half Thus constancy applies to DNA only the RNA ind protein content very very much in sperontozoa and in thymus cells for crample the mounts of the above sub fances ure very wall, in liver cells rery large. Now these findings already give some, though still indirect, evidence. stage of 6.

·22 THE CIEVILSTRY OF FLEREDITY TABLE I The AMOUNT OF Domurtu dao (DVA) N Ca or DYT SHOU DNA NAS 10-MI FLSHES Shart 6 67 515 Corp 32 ) Pie 13 Shad 0.94 AI1PHIBLANS Amphoma 160 Nocturus +8.4 Fros 150 Tond 731 REPITLES Greta Turtle 521 Incer Smal 5.02 Aliptor 49 BIRDS Hen 22 23 Preon 20 Phentot 1.7 VAILLALS O 6.4 60 Horse 50 Ra 5.7 Rabbs SJ kocoke 5.0 From Indeed, the umount of substance stupected to be heredits determinant, should be the same in all cells of all the organs of the smc spears because all these cells should aunty tbc amc number of gena the annount should be tuice louer ja the spermacozoon, which pronably carnes half of the heredity (the other half being supplied by the um) One would not have confidence in a substance tuch and from one organ to another By this indirect evidence then, the heredity deterou nants should be DNA The endence from an early dif ·HEREDITY DETELMLANTI AS CHEMICAL SUBSTANCES 13 ferent direction wu obrauoed in 1941 by Hollaender and Emmons (see also Zelle et am) As will be disctseed furtho on, ultraviolet uradition induces mutations. Matadors by definition art replicable changes of the genes. Hollaender und Emmons determined whuch wirelength of ulos pola light is most effective in mduong mutations, and compared it with the wavelength most effectively absorbed by each of the two aspect substances (protans or nuclac sads) The answer was aguin unequivool the wave length most effecuve in changing the geries was the me most effectively absorbed by nuclac eads and morely dif ferent from the one absorbed by proteins. Thus, the nuclac sacs agun appear to be the geruc material. Such a experiment does not tell us which of the tiro noclec zada, RNA or DNA s most bkely to be the genuc maternal but once we know that the genes are curred in the chromosomes, the main component of which DNA rather than RNA rt is egun the DNA which xems to be the responable agent. In summary then all powable evidence mdiates that the heredity decennino are specal chemical sobrances, 10 particular all proofs indicate that there abstuces are nocleic sack, no evidence to the coorry or tidence for Abrucos other than ouclerc aads has crer beco offered. It would be of interest to see how the nuclac tads art distributed in stare (Table II) One douces first that there to bring emty down to the amplest viser, which would lack this substance. It an be further seen that the two kinds of pocec acid, the obonude iod (RNA) and the deotyribonuclac sad (DNA) are disenbuted very unevenly the smaller viruses, on rale, contain only RNA, the larger-only DNA. As explained before, both are hered- ·14 E CHEMISTRY OF HEREDITY TAELE I THE On of Nuanc Acte N N TU VIRUSTS Tobecco mons ANA Pollodiyotib RNA Influenza RNA Rabbk populo DNA Vectra DNA Bactenoptage DVA FUNGI (bcludmx Bicttta) ALGAE RNA A DVA HIGHER PLANTS RNA and DVA PROTOZOA RNA and DNA HIGHER ANLALALS RNA Ad DNA ity determinants in thar respective bruges. The cellular orgarusons, starting with bacterie, invariably contain both kiods of muclac aads, though o mentioned previously only DNA seems in this career to be prinapal heredity de terminant. It must be mentioned that the cellular nbonu derc acids, though belonging to the same group of chemical mbstences may be quite different froni the viral ribonu cleic acids whuch are herediry determinants; in particular the latter seem to have a higher molecular weight, resem. bling in this respect the dotynbonudac aads, all of which seem to be heredity determinants The atuation for the cells of higher organisms resembles that for the bacterial cell The amounts of DNA for mdı vidual species (regardless of organ) have been presented in Table I the amounts of RNA will wory from organ to or gin The distribution of the two kinds of nudac iads (DVA und RNA) within the cell an be studied by cytochemical methods, uang bagcauns speafic for one or for the other In toother method, one can digest any RVA or D A by means of enzymes hnown to be speafic for one of them. Such czymes are denn nibonucicose (D\dise) which ·HEREDITY DETERMINANTO AS CHEMICAL SUBSTANCESS mpeafically breaks down DNA end ribonuclease (RNAx) which cafically break down RNA. After digestion any base stuin wil reveal the location of the re meming (antouched) nuclac sad. More quantitative as the method in which the truc arc homogenized and the individual cell components are sepse arated from each other by differentul centrfugation (cen trifugation at various speeds) Euch fram can then be analyzed separately ming convenient colometric prethods The rerulus of such m analyms for A typical cell TABLE #1 uu Aco Com O DUAL Courmet o Vs La Car Aktem barbero per 100 grams ASS Cot PT RNA DA hodem SD 23 Atochantra 16 Macromo Voir pertinlue frios Fromn * Fom (mous lirer) are given w Table HI It will be sen dut the ribonucleic saids are dignbued throughout the cell and may conceivably krve for many different purpose, on the other hand, DVA w found only in the churronomes, that s in the apparstw for the orderly transiston of beredity Thas Rruaan eri m all living cells wluch were examined thus far It ss worth while to spend sometime to Ke bou the nu dlex eads can more the genetk informoon and love this formation can change in the process of mataaon thes Robject will be documed m the next chapter Sochi Dudod on or be red abo for bok all (ochede bactes culs * Ex ept of cours cet hati Dva anamo U or Tous less wed the propos @ 15 ·Chapter III THE NUCLEIC ACIDS BEFORE we begin the discussion on the mode of action of nuclac iads, it is imperative to refresh our memory about the basic points of the chemistry The reader who is fa miluar with the general structure of nucleic iads may be tempred to bypass the first part of this chapter however it may be pointed out that new facts about this structure arc constindy forthcoming in this book an attempt will be made to describe the structure as we knou it at present The moleculas of nuclec aads are grant molecules of lugh complexity they can, however be broken by approprate means, to ample building blocks called mucleotides Endi such noclconde is composed of one molecule of a mitrogenous base one molecule of 1 sugar and one molecule of ortbopbospbonc acid (Figures 3 4) There is nothing pe cular about this phosphonic sad but the agar part is in teresting The sugar o of the pentose type (s carbons)* Two kinds of peatose sugars are found in nucleic zadr one is D ribose which occurs in nbonudac iads (RNA) (Figure 3) the other B 2-deory D-nbosc, deoxyribose for short, which occun in deorynbose nuclac iads (DVA) As of the bopening of 1959 tar arbon ou plocos, occun n DVA trun phase in adu Hod to peotuse) but i pecoturity 26 ·HO 0-N R 20110779nx CH N-C-N сн сн(он) се сн сне - A P OH O-P20 HpNGE R 0 HO C-0 HON CH CH(OH)-OH CH OH L с Р 07 0-PO 3. HH-00 H₂H th R CH! OH-OH(OH)-CH CH CHE P OH 0-Po 0CNH HO 0-0 R CH-CH(OH LOH CH CHE HOールー ឬ P он 0-P-0 - 0 Fre} Von coorpoot and Kractart of tortocla at (RNA) ACG ad U naomoc bed den cytun pone und and R-oper D box, Portbophcophone and ·111541DINI VE ILULITI R--H HOO- CH N-0-N A D NUCLEOTIDE OH CH2 CH CH CH2 OH Р OP=0 A HONO-N HC C-o HON- D -CH CH CH CH CHE OH Р OPO с HR-00 イッカーと CH 6 D OHCH, OH CH He он P 0-P-0 -7 G 0-C-NH | она е D Re-- Он сне сн Сн он: OH P O-PO T FK 4 llabn cooponema u grocture of deurtbonuclerk (DYA) T-krog Docs bere thymiae D-2-dotyDibre A.GG OP on Fig 3 ·THE YTOLEIC ACIDS 19 (Figure 4)-benice the maintes of these nuclac acade The de Oxyribose differs from ribose only m that it has one less orygonom on the second curton. This all differepce must hare very mportant implications in mature however acept for the fact that dearytībose s 1 bit more ractive, We are at a loss to grasp why one pogar should be chosen for che noclerc iads of empler virks, and the other sugar for the nucleo aads of larger vertoes and for the chromosomal nucleic sad of higher orgamsung The remaining components, the metogenous bares, ut Trost interesting They can be cosefied into two aregos le the purmes and the primadmes Each of the two ou clac tods contum, s major compoocals, two lands of panges and two kinds of pynimudincs, one for ach nucleo ode. These are adende und guanine (promes in both RNA and DVA) cytosine (a pyrodipe in both RNA and DNA mkang in DVA of certain bactenophages) unal (pyridine in RNA only) thymnc (* pynon dinc maly mn DVA) s-hydroxymethylcytoane (pyntudine co place of cytande m DNA of certun phago) In addrtion to these main components, small mounts of VLNOU nitrogenows bases were recently reported m both RNA md DVA. These bases (not shown on Figures 3-4) are s-methylcytoserie (a pyruodinc in DNA of higher organisms only) 6-methylaminopurine (2 punine 10 m crobial DVA od RNA) 6-dimethylamnopuri (1 purine m RNA) 2-methyladenine (1 punine, in mucro bral RNA)" 2-methylguaruine (a punne in microbial RNA) i-methylgunine (1 purine In microbial RNA) thyminc (8 minor component in macrobral RNA)" As mentioned before, all these base ure located in their respective nudeoada, which bear corresponding names thus, a mulcoade composed of adenunc, nbox and phon ·DIE CHEMISTRY OF HEREDITY 30 phoric ead is often alled adenine ribogde one composed of guaning, deoxyribose and phosphate-guanuc deoxynbonde etc Other names used for these nucleoddas are adeny lic ead and deoryguanylic and respecovely Nucleoside is the general name of a conpound obtomed by the com bination of such a base and the sugar (or ebec obtined by the removal of phosphoncead from a nucleoude) The cor responding names would be adenine nboogde, guanine de otyribosade etc All these components are linked together in well defined ways presumably always the same for 21 ponnes, and the wme for all pyrimidina. All nuclcondes, in tum, arc linked together formng very long chains. Figures 3-4 give examples of such linkages One pooces that the phosphonc ead groups repeat theinselves with #riking regulanty The discances between these groups are always the same 035 one millionths of a millimeter it is exactly the distance benveen che individual amino acids in a protein chain. Thus, the two pubstances, nucleic acids and protens are made to fit cach other nucleoades of one combining with the basic amno aads of the other forming oucleoprotein. Todeed, nuclec sads are never found in nature as such, but always sntcleoprorans from wuch auclac acids themselves can be obtained only by removing the protan part ( deproteinzation ) It might be too boning for a non-chemist to Audy in detail all linlanges in the DNA molecule. As a matter of fact it might have been ready too bormg to follow all these chemical names and formuks, so let us step nght here and just look at the implications. The implications in that the structure of nuclac acid is very complex not less complex tieanche gructure of protein, which as we knor are capo ble of such an sgonstung speafiaty 11e auno sads in ·THE VALEC ACIDS 31 proteins, the bases in nucleic aads may be responsible for this specifiuty What # acrually the meaning of chemical speafiat? And bow an a molecule curry an "information? Conader 1 single nucleodde. By the virtue of its acidic group it will participate in some racions, by the virtue of is hasic groups it will participate to others. It may also ca alyze certam reactions But the one and shape of the folc cule and the distribution of electrial charges in it are such that a nuclcoude will by no means partiapate indicam nately in all the reaction the molecule us choosy, it has a certom speaficzy In other work, by virtue of being it self the molecule cand certain chienal informaaon. the LATUCIon us to reactions m which it should parapate (ut a reagent or us a catalyst) and us to those in which it should behave indifferendy The mount of information arried by . Angle oocleoade small its such a mall molecule. Bar if one links to gether 1 great number of them, then the individual mall parterns of clecencal charges are added and for a large very complex pattern the molecule will now be very choosy lodeed But there are only four different major nu deondes (two purme ad tio pynmidine nudeoude) in ach nuclac acid ad therefore they are repeated If the four arc repeated in a regular way always in the same or der the pattern would become monotonous ind no further gan in complexity or specyfiaty would ever be posable The scoctly the reason why the chemists for a long time disbelieved that the oudac nads, especially DNA, could KTVC 81 crner of genetic informadon. they thought that the noclac iads consigt merely of repeating was called retronucleotides, composed of one of each of the four ouclcoudes' Such a repetitious molecule would be very uninformative, indeed morcover all the molecules of DNA ·THE CHENILTRY OF HELEDITY 32 of all the specs would have to be the same god obriously could not ste u amcs of different hereditan charac ters. As will become dear further on, the scquence of mu cleoada in auclac sad u very megular and the "tetra nucleoade" unit simply does not cost but some thirteen yars ago few would dare to doubt it, such was the author ity of the author of the tetranucleotide theory a destinguished scientist P A. Levcue. One chemist (Lehman Echternacht) even reported the actual isolanon of the (purely ficticious) tetrinucleoade" and secungly the case 11 dosed Not quire. The tetrunucleoude theory was amply based on a wrong chemical analysis, according to wluch the four nudcoades were present in cqual amounts. In 1947 Gol land reported that the results of otroon of nuclac 2010 somehoir did not support the theory However Gul lands dare were also wrong Chargaff and his collaborxtors undertook the accurate analyses of nuclac aads they found that the four aucleotides were present in very uncqual amounts and therefore the recranucleotide theory cannot be correct" The proportions of individual ponnes and pyrimidines were different in DNA of different speacs (Table IV) therefore, there must be not one, but many different quclac iads. On the other hand, the DNA from different organs and different grans of the same spe cies exlubit the same proportions of individual purines and pynimdmcs (Table IV) These proportions are independent of the environment. Moreover os mendoned above, the sequence or distribuaon of individoal pumnos apd Рупmdma m cach nucleic sad is mos irregular Now this Atution is to be expected if renow deoxyribonuclec eads are to be heredity determinants they sbould be different in different species but samlar in different aruns or differ ent organs of the Ame speaes The molecules of DNA ·THE VUCLEIC ACTUS 33 TABLE IV The Propogor I DCAL Pam Anubot N DNA OF SMALS Mino Rasies Ada Tot Prints Smoc Criantes Pyrhoudines ANIALS Alin (sper) 1.6 13 0.04 (that) 17 135 107 (threr) 1 42 10 1.09 Or (pem) 129 131 1.037 (thyes) 1.19 113 11 Sherp (apiten) 1.26 1.36 1.01 Gost (sperm) 131 13 1037 Horn (spleen) 1.29 1.37 11 Rart (bond DLITO) 134 1.39 1.00+ Hen (erythrocyte) 1.45 1-29 90 Turtle (ory chocytos) 131 1.31 103 Salon (CTTO) 1.43 1.43 1.02 Hering (perm) 125 1 32 1.007 Troot (perm) 132 L.36 1.1 Shad (totes) 1.3 143 101 Locust (whole) 143 141 0997 Set Urchin Ecboard bow Condo 193 170 100 HIGHER PLANTS Wher (m) 1 22 102 1001 LOWER PLANTS Sacchets Ontde (Baker Tort) 1 67 192 1.00 Exhericbic 0.95 101 SUTTOM COCO 076 0.63 0.92 Mycobacterhom tabetolos 04 04 Homepbih banda 1 75 154 1 01 Serpeernd 145 175 10 RICKETTSAL Riceto porrect 2.07 112 ANTAL VTRUSTS Grymoth pob hodni 07 107 Ved 100 BACTERIAL VIRUSES E porto T 153 2.99 From u + The data do rrarhed odhoda nechty todoc. IDE 1.31 ·THE CATALUSTRY OF HERODITY 34 should be complex and irregular to be able to carry very speafic information The further we probe into the structure the more weird It appears tracts of punnos followed by traces of pyn midines may occur in certain sections complex intego larity in others. All these patterns are sul pianingless to 13 we have not yet been groted the insight into the most valuable of natures irritings. But we know enough to suspect that this pattern or sequence is the rey code of bereday the device to preserve genetic contmuity If we calculate the number of possible patterns just by changing the positions (xequences) of ndividual purines and pyrımıdmas in a molecule of DNA (of just one over all companion) we amve at the figure of 10! ** It as e large number certainly large enough to take care of all the genes which ever did or will cuxAnd all the mos based on the sumption of four bases only As mentioned before, there are also present in DNA small quanaues of additional bases, and there, the raisons in the ahe, an add a lot of flavor to the speafiary of DNA In addition on must not forget that our knowledge of the DNA molecule is actually in its infancy thus, many other features which add speaficity could soll be discovered While the discusson above centered speafically around DNA, much of it can also be said about RNA. The role cule of RNA may be somewhat smaller but it is still suffi cicatly long for specfiary It is just that we do not know as much about RNA as we know about DNA The reason for it becomes plain upon looking at Table III gun The The dhortbotion of oro cits in protens babo mor Irrorular mon that the latterton, CT) sery specific information, though pot fonetic puformation be etely alculated the the trenber of foderduik hicho ho frer abied oor pertas could not be been higher than ID tu TB probably lower the 10 It a ·THE NUCLEIC ACIDS 35 DNA is atuated in the chromosomes only it seems to have only ove function and is congdered to be one type of ab- #ance. On the other hand, the cellular ribonuclac acids seem to be everywhere each in its own att my serve 1 different function and be a different substance Indeed, nbonucleic aads from different parts of the same cell were found to have different comportions (review mn") Such a atuation wus bound to slow down the research on cellular RNA. there just are not enough scientists to go around Ou the other hand, the heredity determining RNA of viruses are angle substances, mod connderable progres las been tchieved especully in the sady of the RNA of tobacco moon virus. Such RNA has grant molecules, though apparendy not quote es giant as DNA, the latter may have a molecular weight of 6 quillion (about 20,000 nuclcoades) the former 300,000" or 2 million The tetrinucleotide" theory in RNA I just u invalid o in DNA, and the reg olar distribution of individual pannes and pyrimidinesjust as bewildering There may be, however some differ ence in the spacnl arrangement of the two audac sada While the scientios were enjoying the implications of the megwarides m the structure of nuclac acids, certain regulaties were also found The most important of these us the fact that the ratio of all purina to all pynmdina in any DNA u always equal to one. It BB of one purme al ways formed a pair with one pyrimidioc Thus thought led to one of the most exhetic concept in modern bloches try the now famous model of the DNA molecule of Wat son and Cnct" It was supected for quite some time that the molecula of some proteins may have a qural configuration, and that two or more Arch spinals could be wound around ach oth on space, hkc threads of 1 kre* Now the dienbutron of atoms in a mokcule em be morired by means of a spe

·36
THE CHEMISTRY OF HELEDITY
cul techoque called ray diffraction. On the basis of ach
motsuremes for purines and pytınıdına \Vusons and
Crick proposed that the DNA moleculc es composed of
to completatenitory spord stands which are woood around
cach other (Figure ) Each strend would actually be a
The
Fus on-Cock model of molecule of DNA
rabrany
denore the orphosphate stains and the horrortal berythe poln
of botos holding the chom together (Serfet)

·THE SVOLC IODS 37 string of nuclcondes, os shown on Figure 4, except that it is 2 sprral in space and not a flat figure. The arrangement of the spiral such that the phosphate bonds an ach of the (ho spols aick toyunds the outade, whereas the pormes ud pyrimidines towards the inade, facing the couple mentury pytumdines ind punnes of the other spirul. Here Il tron and Crick utilized the previously found regulanty (number of punnes o equal to number of pyninudines) the most logical mode is such that a panne in one strand always facts a pyrimacme na the other The members of much a pur (punne-pyrimidine) ze sctually so dosc in space that their most prowmal groups can forin chemical bonds. These bonds are of the hydrogen bood" variety they are not ss etong o for cumple carton to curbon boods on chiamcal compounds, however once a molecule of DNA may have os many as 10,000 of the porine pyn mudine pun there are so many of these hydrogen boods that they part to the DVA molecule quite a remarkable stability As will be seen further on, come DNA molecules mil withoomd boiling for one hour few of my brologically active proteins would be that stable. According to the alculations for distances m space, the parts do not fit together of purine faces merdy my py mudine it has to be altyays so that adente faces thymine und gumude faces cytogos, or vice vere (Figurt 6) Esch of these u utato alled a complementary pair Now 1 moment of thought will convince ws that the atmoon re sulos n that the two truds are also complementary : grund with a speafic sequence of dividual pannes and pyrimidus an pair only with a very specific grand that is the one with the complainentary (but not the Ame) se quenct. Thus, each and determines the sequence in it part net cach, then, musst anty the enare information Thes ·38 THE CHEMISTRY OF HEREDITY S-A- T-G G- . G-S S-C- -G-S S-A -T-S S-T- A-S Fa Purny of purno od pytanedenes m the lletro-Cnck model Adenunci G-ruanne 4-cytomme T-thymore. S denota ar (de atyrbore) ml P-phosphate Solid na-foglakont boots broken boner hydrogen bonda comderauons led llacson and Cock to the second proposal of a mechanism u hereby the molecule of DNA can replicate without losing or changing any of its informa tion The mechanism is besutfal m its sunplicity when ready to replicate, the two grands separate (by un and ing) and each rebuilds is missing partner Esch grund an theorcually do it because cach carries the full informanon consequently there will be tud idenocal molecules where onc arised before. Nou most sentis ure artes at hart and they were moved by the logical cheties of these niodels as a result, the acceptance of the models did not encounter the rest ance which usually meets net and bold concepts. But some sentits recall the purfalls in screpang a concept because of its supliesty the terrinudecade theory" can serie aus ·THE LEIC ACI 19 one prople. Thxc antics potat out that the 8-124 diffnectvo Audies, on wtuch the moder basert, account at beg for only half of the structure the other half like the other half of the moon, is invmible and cooxcavably an fur nesh sone surpruit such us skut ade curs, chemical link ages different from the screpied onet, etc. In particular it stili difficult to fit into the model sone of those bases whach are present in DNA gull quantities' By and large, hower it is felt that with all the timestsons m mod, the 11 lemon and Cock model sol so the expert mental dan best for a least the excentral part of the DVA molecule The original ancept of the mechanism of repetcuon (separtoon of draads) loss Rimulated considerable speculoom as a result man essentially equivalent mechas um of repkaston have been proposed (renew in ) The banc concept of Watson and Crack has recem bom upposted by the results of the serious experiments of Vier clima md Seahl These sentits grew bacters on medium Conting a heavy botope of merogeo (N) so that all the substances as the cell meloding D1, because labelled with hery nitrogen. They then grew these bacteria for tuo generations on ordinary nitrogen (") Kolated the DNA and, by means of an ingenious CW cenifugaon schod, determined on the heag nitrogee was dienb wed anong the DNA molecules. The result was that half of the molecules had some labd and the other halfonly A monent of thought will corrvince ws that thes remalt clearly rapports the Wako snd Croch model of DVA replicador dunng the hors division on V medium, the two strands of such molecule labelled with N became Keparated and excha rebult the mossing sind, using the only truitable surroyen that is ordinary ac Thaisuke solche !! HOUSEKS to profond for the art mode code ·40 THE CHEMISTRY OF HERIT consisted of onc old strand labelled with N and one ncu grand labelled with Ni danng the second dirigon the strands separated again and the ona containing only N (half of all the strands) rebuilt the mining ones, also with N consequently such complete molecules (half of all the ensuing ones) wall contun only N Thus, it is very likely that the individual strands do not break down dunng the replication and that Watson and Cnck were correct about the suggestion as to how the molecules reproducc in the cell Well, obviously in the cell" After all, one cannot reprodact nuclac iad m otto that would almost be the creacon of new genes in the test tube, a science fiction guff Onc cannot? As in many other fields, science as catching up with science fiction and below as the report of such recent fascinating endeavors. In 1955 Ochos and Grunberg A1anago were working in New York Univeraty on an enzyme polynuclconde phosphorylase whuch removes the second phosphate from nuclcoadc diphosphates and attaches a phosphate from the medium instead. Now this second phosphate in nucleosides 13 1 very mteresting one it is linked to the first phosphate by a so-called "pyrophosphate" bond which is known to carry high energy thu, much 1 nudcoadc diphosphate a capable of many reactions requiring energy such 3 syn thetic reactions. When tus reaction was performed under special conditions, the liquid become very viscous' ind would not een fou out of 1 beaker turned upsade down vadently the enzyme in the beaker had synthesized 1 high molecular y aght substance from the small fragments. The saentists realzed the importance of the discovery and de vored their full effort to the cluadation of the phenomena jorolved It was soon found that one can obtain at will, a product which has only one kind of pucicoadc (for et ·THE NUCLEIC 4D5 41 ample a paly adenylic aad) or 2 product wuch has two three or all four this last substance ws smiler to s obo nucleic acid. The grou chemial composition, the kind of chemical bonds, the structure in spect, coco certun iunil iary bologial properties, all were cquovaleat to those of natural RNA (revicws in ) But, as will be deemed later on, the main biological role of cellolar RNA u largely unknown, and to 1 a chemical method for findmg the fine gructure of RNA. Io vich of the lack of there one cannot be aure that the RNA like substance indeed has a proper sequence of nucleotides or carries the proper chemical in fordon. What was worrying the scentiso was that they could not put their finger on anything in the beaker which would tell the newly synthesized substance what the se quence or mformation should be. The synthesizing ett zyme? No, this is unlikely because onc enzyme is supposed to synthetze all kinds of molecules of RNA. Some sort of a Hinter (here called pomer") which would make the new molecules into its own mage> That would be mort logical, It would also best fit the concept of RNA repkcation m Otto To date ach a pozover has not yet been found Per haps it never will be perhaps the synthesis of RNA s more complex and less mdependent than one thought It us, how cver of interest, to note that the small fragment of RNA, contunng few specific nuclcondes, were found to speed up the synthems of larger fragment contnning tbese spe atc nucleotides, thus serving # e land of sumphfied pot Dier While this was going on in the field of RNA sudios, a group in St. Lots under the ladership of hamberg discovered another enzyme which nthanas DNA # HITO (revcu in ) The enzymc, fix found m bacteru (Escber icbus coln but recently reported to be proxent abo in mm- Varch, 1959 ·THE CHEMISTRY OF HEREDITY 40 conasted of onc old strend labelled with N and one neu! strand labelled with N during the second divaon the grunds separated again and the ones contaming only N (half of all the grands) rebuilt the misang ones, also with N -consequendy such complete molecules (half of all the custing ones) will contain only N Thus, it is very likely that the individual strands do not break down daring the replication and thuat Watson and Coch were correct about their suggestion as to how the molecula reproduce in the cell Well, obviously “o the cell After all, one cannot reproduce nocleic iad TR TTITO that would almost be the czcioon of newy genes in the text rube, a science fiction stuff One cannot? As in many other fields, science o catching up with science-fiction and below is the report of sich re cent fascinating endeavors In 1955 Ochoa and Grunberg Manago were working in New York Univerph on on enzyme polynucleoude phos phorylase wluch removes the second phosphate from nuclconde diphosphates and attaches a phosphate from the medium ingcad. Nou this second phosphate m nucleosides 1 a very interesang on it is unked to the fire phosphate by a so-called pyrophosphate bond uhuch u known to carry hugh energy thus, such a nucleonde diphosphate capable of many reactions requinng energy such as synthouc reactions. When this reaction was performed under special condicons, the liquid became very yacous and would not even flot out of a bealer turned upside down Evidently the enzymk in the beaher had on a lugh molecular weight substance from the gall fragment. The scientist ralzed the importance of this discovery and de vored thar full effort to the elucidation of the phenomena ini olved. It was soon found that one can obtain, it wil, 1 product which has only one land of nocleoude (for at ·THE NUCLEIC ACIDS 41 mple a poly-adenylic aad) or a product wluch has the three or tu four thus last substance amilar to a nibonuclee nad The gros chamcal composition, the Land of chawal bonds, the ancture n space, cren certan aurlwry brological properties, all were equivalent to those of natural RNA (reviche in ) But, us will be discussed Later on, the min biological role of cellular RNA s bargely unknown, and so B chemical method for finding the fine #ructure of RNA. La view of the back of these onc cannot be sure that the RNA-Ic mubstance mdeed has a proper xequence of nucleoades or ames the proper chienal in formation. What was worrying the scientist pres that they could not put their finger on mything in this beaker which would tell the newly synthesized substance what the se querce or information should be. The synthewing en zym? No, thus is unlil dy because one enzyme as supposed to synthesize all kinds of molecules of RNA. Some sort of a starter (here called primer') which would make the new molecules into 10 own image? That would be mos logical It would also bex fit the concept of RNA replication m OttTo To date such a primer has bot yet been found Per haps it never will be perhaps the synthesis of RNA w more complex and less codependent than one thought Ic , how cyer of mterest, to note that the wall fragments of RNA, contuming few specific nucleonda, were found to speed up the ryotheus of larger fragments containing thoxe spe afc nucicondes, thus serving as a kind of complified pri mert Wbulc thu wu gang on in the field of RNA studies, a group in St Louw under the leadershup of homberg docovered another enzyme wuch synthesiza DNA m titro (rever in ) The enzyms, fire found m bacteria (Escber tobus coli) but recendy reported to be pretent also in mam Varch, 1979 ·THE CHEMISTRY OF HEREDIT mals seems to work on a different pnnciple than the en zyme which synthesizes RNA For one thung the starting materials for DNA rere the deoryribonucleoadas art ing to, rather than onc, extra high energy phosphate groups. For another thing the syntheus would go only if all four deorynbonucleondos vere present indicating that che enzyme has indeed all intendons to make only a good DNA. But the main feature was that the enzyme really needed a primer a pre-casting rolecule of DNA Once such as present, the synchus goes ahead, and the nculy made DNA (up to cuenty times more than originally put in) has the came base compogoon us the primer** Thc origin of the Czym does not matter the cazyme from bacterium Escbericbu coli given human DNA as a primer will synthesize a product of the base compostion of human DNA. The proportion of the individual nuclcoudes in the mixture does not matter either the product always follows the pomer Onc now ash again does the product possess ako the fine composton (the geneac information) of the natural DNA given as primer? To answer the question on should use i pomer having some biological activity (such as the transforming procplc) and then test whether the syni theac product also has thus activity To date such an ex pennent could not be performed because the preparanon of the synthesizing cruzyme call contained as impurites som deorytibonucleash an cnzyme which causes rapid destruction of the transfoming principle (see below) When the expenment will be finally performed it may still turn out that all the enzyme an synthesse a un artifact devoid of genetic information (son called DNA") Should, however the syntheas of the active trans forming prnaple be attained, then we would be witness- Larch, 1959 Mensere ·THE VUCIC ACIOS 43 ing a cruc reproduction of naked genes in 1 tex tube, a fun tastic, pertaps fnghtening achievement. In the meantix, organic chemists are #riving to synthe aze fragments of audac aad in 1 purely chemical way without the enzymes Vinous surting materials (nucleo adas, both abo and dcorynbo-) con now be synthesized at will, due to mahods developed mainly by Todd" (Nobel Prze 1957) Vang these building blocks, Michel son" has acceeded in synthesizing fngrxents of RNA, and Khoren -fagments of DNA, by pure organic syntheas, without enzymes or posers. Moreover the compogtion and cven the sequence of nucleotides an be con trolled at will. There fragments, however are rarely longer dan is nocleotides; putural DNA may have us many as 10,000 10 one grund, so it saill a long way to go. Further more, although the fraginents are most weful for many purposes, the cyathees of e nudenc iad carryrag geactie informabon s unlikely to acceed in this way m the absence of a paurer who is going to tell the chietist which sequence to chooss, out of to posible once in all our dikusnoms we have tased the word mole culos, in the plural form this, however should not imply dut the molecules of DNA, from one cell for example, art all alike. How could they be? After all, they mux represent different hereditary characters. The scientists long felt that auch molecules indeed most be different perhaps cacb molecule of DNA in the cell o different. The experimental cvidence for thus belief wu furashed again by the trusformung phenomenon (ree previous chapter) in transfor moon os a rule only one hereditary character at a tine is trasferred, us if ach character were mdeod stared in a different molecule thus, the moleculos must be different The direct proof that they are different has been furnished by Charger et af and others " It sous found that by spc ·THE CHEMISTRY OF HEREDM cal methods one can separate the DNA (from one type of cells) mto separate fractions which differ in thar base conposition Thus, the compositions given in Table IV or m dced any other chemical or physcal properties reported for DNĄ, are always merely the aerige properties Now it would be very nice if every gene" trould be located in a different molecule of DNA but one might ask an embar sang question are there enough DNA molecules in a cell to go around? The answer is many case not nearly cnough. Talc for example a cell of bacterum Hevropbilus rafblenze its a small cell, but nevertheless very much alive. Now one I accustomed to think that there are millions of molecules of crery aubstance withun the cell yet thus cell hos only 200 molecules of DNA That is all Clearly a living cell must have more than 200 gens or chanctens. Perhaps, then there is more than one gene to a molecule of DNA? Recrot endence indicatos that this indeed may be so Upon closer cxamunation, it was found thar in corde transformation expenment cao chur Iters may be transferred together us if they were baked in one molecule of DNA" In this way cells were obtained which never crossed in naturc monsters having turo apsules in place of one In another case, the linkage of rao characters has been obtained as a normal fature and in recent years auctotis reports indicate that this is indeed & rather common pbenometion. Just hot many heredir determinand an find a place on one molecule of DNA? Recent speculations based on the determination of the vul nerable segment in a moleculs, indicate that one aan derde the molecule into 6 to 10 parts and such parts will will be acare" But from the field of bactenophage studies comes another approach Berzzer has performed a paint Aber kero Erbach am above jong malamalo od DI honen baptold cell has about 150,000.

·THE XOAIC MW 45 nahing study of crossing over in plage ( procta alan to CTOS-Opet in the chromosome of higher organisms) and carxe to the conclusort that on the basis ut of heredity (stretly saking watt of crossing over) would be no ongker dine few nucleoede, if so frere would be thorands of web muts per bele molecule of DNA. In any cast, the feelings that the old notion of ouc gene per mola cue definirely oatmoded. Qordly connected with the antepr of the "se of the ourker" is the problem of four how much one can inpure che inolccnle of DNA without producing i MVADOT Or change. The problem as important #hat bermy da che phenockOn of killing by radation and the process of mati- LOT 2 Before we an embark on the problem of injury w DNA ut mot deade what we want to call the monjured or ma ove" DNA Ac prexentru not know whether an even most are felly msolated DNA preparim can m al respects bc iden ooi with the DNA sicensed in the bring cell the DNA never found in the cell as auch but merely aa part of nudenotes, which en turo, may have band's to all other substances. The term paine" when appled to the propa mation of DNA to B therefore rather misleading whac thus raly rocans A that auch a preparation clubass der un futuro woch it must have had then it wa in the hong cell The most obvious and the most important of theme features the proper biological Activity lc o mdeed 1 feature of which one can pidy ay could not have been created erofically by the practs of solation Such to ac Ore DNA preparano may be called functionally hatery and on IT AS syurdich obviously is properties are MTOTC Coint and are of more materest than the properties of the products of an undetermined degree of deaton ·40 THE CTILNISTRY OF ICREDIT non" in particular the studies of the funcdonally intact DNA preparation may lead to correlioon between the function and the structure. As discussed before, the transforming activity is such a proper biological activity which can be demonstrated in certain bacterial DNA preparations: these co therefore be called functionally intact Having this yardstich we can now Aubject the DNA preparations to venous treatments ind see what these trement do to the biological activity and what they do co the physical and chemical properties of DNA Onc conspicuous property of DNA in solution is its high viscosity the property is common for all hughly ASYTHITTIC paracle. By asymmetric it u meant that the molecule o much longer than it sinde, and DNA s 1 tvpical example It has been menooned that DNA has a high molecular weght (about 6 million) because it composed of so many nucleoddes, a compound of thus sort is called e high polymer As stated previously these nuclcoudes art arranged linearly (see Figure s) in the form of two long intertwined thrads, so that each molecule about 8/10,000 of a millimeter long though only 1/400 of that in diameter indeed, a highly asymmencal structure when fully extended. If we now heat the molecule above 180 F for one hour or the molecule will collape and become less asyonxtrical therefore, the solution will be less nis- Cous. At the same moment, the brolog.cal activity will de CTERSC, and this serras as one of the indications that the biologial activity is indeed veeted in the bugbly polynier rzed uninjured DVA Other injunas can be cured by zad (below pH 5) or alkali (abore PH 10) aod, for ce ample, can breah some of the phosphate bonds or split off purinos thus will make the thread shorter and devoid or onginal mformation"-again the loss of 17scosity and the Joss of brological activity start at the ume montent De ·THE NUCLEIC ACIDS 47 oxyribonudesse (DVitse) the enzyl which breaks ( depolymena") DNA, and DNA only o even more harmful. Strong DNAases are present in pancaic juice and in the secretion of certain hemolytic streptococa, but peafic DVAves are present in every cell though they may be inhibited so as not to nse too much damage when the cell suill alive Now if one confronts DNA with us Iittle us one millionth of 101 weight of pancreatic DNA, the latter will break enough phosphate bonds so as to com pletely dextror all the biological activity within 20 minuces the decrease in viscosary follows later on. The action of this speafic enzyme wu one of the orginal proofs that the transformong principle is indeed DNA. Alany other agents can readily destroy DVA Ainong then, the most interesting are those which are also known to be onstagenic agents Thus ribject will be discussed in the next chapter ·30 RE CARRILTRY OF HIREDITY gon" in parcular the audies of the functionally inact DNA preparation may lead co correlation between the function and the structure. As discussed before, the transforming activity is such a proper biological activity which can be demonstrated in certain bactenal DNA preparagons, these an therefore be called fanctiomally intact Having thus vardach we can 104 subject the DNA preparations to various treatments und set what these treatments do to the biological cavity and what they do to the physical and chanical properties of DNA One conspicuous property of DNA in solution 13 108 hugh viscosity this property is common for all highly asymmetric particles. By symmetnc it is meant that the molecule is much longer than it is wide, and DNA is a typcal example It has been menaoned that DNA has a high molecular weight (about 6 million) because it is composed of so many pocleondos compound of this sort is called & high polymer As stated previousdy these nucleotides are Arranged locarly (rec Figure 5) in the form of two long inrertwined threads, so that each molecules about 8/10,000 of a millimeter long though only 1/400 of that in diameter indeed a hughly asymmetrical structure when fully extended. If we now heat the molecule abone 180 F for one hour or fo, the molecule will collapse and become less asymmetral therefore, the solution all be less 12- cous. At the same moment the biological acanity will de crease, and thu serves as one of the indications that the biological activity is indeed vested in the begbly polynner med unnjured DNA" Other injunos can be caused by aad (below pH 5) or alal (above pH 10) aad, for ex ample, can break sote of the phosphate bonds or split off punnes thus all nake the thread shorter and derord or original informoon"--g210 the loss of viscosity and the loss of biological sity cart at the same manent De ·VIUTATION 49 As decused in the previou chrapter, the only chemical substances known at present to fit the role of heredıry de terminants are nucleic acids One should not exdude the porability that some oches abstance such us proten might some day be decovered to also possess thc properties of heredity determmant. Bat right now we know only about nadlec aads and that is all we can discurs. We know for matince, that if we mfect the cell with audac aod from 1 mutat virus, it will reproduce in the cell os nuclac ead of 1 mutent virus. If we transform the bacterial cell with DNA from a matant cell such DNA will reproduce es dhe one from the mutant cell in other words, thc putated DNA will reproduce u mutated DNA. Now what u a mutared nucleic aad? What change in what feature of the Structure of nucleic sad o retained upon reproduction? In other words, what is the chemical bass of mutation? The answer I we do not know but we can make some mtelli gent gueres. As mentioned in Chapter III one guess is that the specifiary of nudeic iads may reude chiefly in the sequence of various nucleoades. If the aunton were rally ** ample as this, then muution would be just a change in the sequence of nucleotide. It would be difficult to visual ze how such a change could come about, upless it occurs a fault during the replication of nuclec iad. Indeed, en dence has often been presented that mutacions can occur oply durmag cell dropdon (Le, daring the synthesis of nodec nads) Burt cydence to the contrary has been re ported as well. in Drosophila old spermatozoa include mote matends than the young ones in bacter, 2 certain proportion of mutations also occuo during the resung (Paborary) stage (Rym et al*) It appean dut the de con for 1 mutational change con somehow be registered in the resung" molecule of nudac tad though the actual circution of the change order occurs later in the name of ·50 THE CHEMISTRY OF HEREDITY cell division. What could possibly be the form in wuch such a decison to mutate is imprinted upon the molecule It has been observed that in inany cases a delay c.custo be tu cen the moment of acon of mutagens and the actual production of a mutant in certain instances the prospective mutants can still recover during thus ante All these observations taken together have led several scientists to suggest that perhaps all the mutagens do is to bring the genc to an musible face, from which the genc an either revert back to normal or turn into a mutated genç the latter process could cake place cren in the ab kence of the mutagen (for e revient sce') Such a hypothe- As would also explain why mutagens wtuch crot upon the genc an cnarely different influence (such as irradation and mustunl gas) may result in prodacgion of the same kind of mutant, Unstable genies that is genes which have high spontane ous mucation rates, have been found in nature in many or ganisms (Drosopbila maize bacteria ) The strains carrying auch genes are not necessarily freaks they may purvive and cien accelerate cu olution" Unstable geres can also be produced in the laboratory (bactena ) by treatmenos rinco amilar to those which will produce unstablc DNA M TTO perhaps we are dealing with the Amc phenotncnon The chanical nature of the lajury in rolied is not clar some bonds must be broken which ren ders the molecule less resistant or less ngid, though sallacuic If the injury o not repaired upon reproduction, a per petually unstable anain may result. Tuming now to the descuenon of the mutagenic agents themselves, one gumbles upon the textbool dirigon of mu tations to tuo classes. spontaneous and induced A mod ern scienast who does not believe in miracles, must usume tuc the sporciocous mutu011 are also induced by muta ·VIUTATION 51 gera but the latter are largely unknown mod are with us all the tune. The problems of temost importance the phe TOmere mvolved may govern the potansons inadence of some types of cocer ind some herediary diseases, the spontaneous appearance of reostanet to annbrocks in mcroorganisms, and last but not loss, evolution. Accordmgly the saentist hare giren considerable attenbon to the ques Hon of what there unknotin agent could be pertraps the oldest and will respected hypotheses o that the culprits are the therral osallitons which of course are always with puch oscillations on mere OCC Rong may mfiict an injury (or course faulty reproduction) in a large molecule of the gene Another suspected crusza were natural sadano (commc rayx radioactive clement m the earth) wluch are known to induce mutations and are always with us. How crcr it has been calculared that the level of exch radiations W too low to hcow for all poatuous mutation Then, there are cheinseil mutagens to consider the Imotvn chemical murgers are discussed below (under "in duced mutations") but there may be many unknown one within the cell the naturally occuring adenined and vott min C (ascorbic acid) have also been reported to induct mut oons. These to pobrances are necessary for life the may curoatically men that we cannot live without moroutions and evolution Some of dwe recorded spontaneous mutaboo rates for 3 few representanve organisms are listed m Table V It cao be seen that, in gtzeral, mutation is a rare phenomenon, by mod langs heredity proceeds without dourbance. Som special, the famous Africio fish codecanta reptile ratara, and crent che ordinary Oport and cockroach, are report od to look the same today as they did over so million years ago the motion rate in these species may be quite logy Belort the pork t ·52 THE CHEMISTRY OF HEREDIT TABLE ELS OF SPOTTANEOC Alor mox RATO Hosting 10 10 10- 10 Vitather Specio Rot Rdorra Luctor plus 10 Escber the call Subke mins Streptomyco rebance 10 100 Streptomycn dependence 10-1 100 Phase rolama 10- 10+ 108 Penicillin resance 104 109 Luctose noo-terrocation 10-10 102 Hacere dependence 108 Unstable in Lector non-fermenton 2 10 101 Hwedne dependence 10 100 Roczton to fall guta colony 10- 126 Ze mwys (coo) Shrunken xech 10- Parpl color 10 10 Dropbil Average lethal ene la the xcond chromogorde 10 Epilon 10 10, 109 Retroblastoma 14 104 10, 109 Abbrono 10 10, 109 Congenital toal color blanc 10, 109 Mikrocephaly 30 10-1 10, 109 Hemophilm 12 10 10, 109 indeed. But, in general, one cannot say that a given spontancous mutability s a characteristic of a species us men tioned previously (see ako Table V) unstable genes may CIIS cren in otherwise stable species. In citremne cares xud sed on Drosopbils up to 95 per cept of the progeny ire mutants" The really looks like a break down of the order ly process of missoon of heredity Such phenomena hare been called mis mutations they occur nurdly and thus far hare been reported for angle genes only other uzee the organism probably could not survive. But in less entreme cases, the mctered spontaneous mutability of ser cral though not all genes m the same cell has been found 2 26 10 ·IN, 1 1.1 MUTATON $3 What is the chemical bass of it? Some len tabla DNA molecules! A sclecare mutagen in the cell? The writer of the book (who, madencally stated) thako that thos w a very mportant problema. The induced mottas are produced by subjecting the genetic matcral to a vinety of known agents (mutagera) the comparsovely higt utapon mies to obtained are permpored on the rather low sportoaneots ration rates Some of the typical trong mutagens are listed in Table VI The table zlo liso the possible effect the agent could have on DNA The most pronounced baroc uong the genser seems to be due to the action of little grenlos called free radovas TABLE VI Ew or STM Alur Acom fraction of DNAH Thoot Padle Efra ou DNA dathiry RADIATION Lorrety ako probably Ulldet, Xaored by tre medical pro Strong dood by the art HLATI Breaking of H-band college n the molec Saony SPLF-OXIDIZNG AGENTS Lindy ako protu.bły Ferrugu on word by free musical per Acorticada doctd by the tptet Strong MANGANOUS HON Unkno Noce ALKYLAITNG AND ESTERLIFYING Allyloton, probety at the AGENTS nitrofea o prope and som Suod nutron DOC stification of not ord on out Strong Dimethyl bort allt da bude Aproplolactone, ett. Frare + Fron Troch NO ·54 THE CHEMISTRY OF HEREDITY The free ndicals can be described as very short lived and therefore very reactive chemical fragmeits (such as HO, or OH (note OH 100) They are produced by the action of radiation on water by self andızıng substances (such a ferrous 10ns, ascorbuc iad etc.) and by many other proc esses. The chemial nature of the action of free radicals on DNA in a living cell as still nor dar despite the voluminous hterature on this subject The action of mustards and other so-called alkylaang agents es better Lnown. These ageno attach thar alky? group to the purines (but not pynmidines) of DNA on the nitrogen in pontion 7 Gosing the nitrogen to assume a posove change. The agents also produce extcnfication of the phosphate of DVA Boch chese effects art Incly to ause disturbance (unstabilization?) of the DVA molecule we do not know is yet much of the tuo is more harmful It » probably creer to destroy a gene than to change it thule still active It has been suggested that the processes lading to muration and to death, caused by matagenic agents, are cassentially the one with the exception that the lacrer is accompanied more crtenave molecular changes. If thus is indeed so, then the traction of DVA by these agents could be a demonstracon of a "too grong mutation" (mputation wtuch us lethal to the DVA) In Table VI the inactivation of DNA transforming proaple) has also been mdicated. It will be seen that, in general, the transformog prinaple is forsture to all strong motagens. This fact may suggest again that the DA s mdeed the site of thar mutagenic action. Ic has also been found that the individual getics in the same preparation of the transforming principle (DVA) may have different abilities tomads mutagenic agents Thus, if a cell us balled by un dabon, some of the genes are ·LUTATION 55 mactive wherets ortions may rerum active. The physicochemail mature of this chifference is grill unknown the dif ference in length of the individual molecules of DNA has been indicated us one of the factor Insinuch u mutations ure serioudy congdered to be one of the causes of some types of cancer it is of interest to docus the cocmogenic agents from the point of view of their action s mutagetuc agenu in general, and of their reaction with DNA in particular These agents an bc ur bitranly divided into two days 1) those which are mm questionable strong mutagens (e.g radiaton and mosturds) react grongly with DNA and even in ampute doses macame the transforming proape and 2) those which arc weak or questionable mutagens (eg cranogenic hydrocarbons) do not react with DNA and have no effect upon the transforming principle. While the first dus fits nicely to the theme ancer-muuton-DNA, the second clas docs not, and the speculations concerning this failure have not been very fruntful. Closely connected is the subject of cermostate agents Lc the agents which check the growth of the cancer cells Theoretically any agent which interfere with the bife of the cancerou cell , m a way also i carcinosauc agent. The choice is narrowed, bowever by the requirement that the agent does not interfere knoody with the life of the normal cells. Among many ageous in the now very active field of cbemotherapy of cocet the favored ones are those wtuch interfere with the DNA of the cell Here, too, the igents can be arbitranly dinded into several classes. To the first class belong agents (eg, vanous moustards) which are knowo to be mutagetuc (review in ruct strongly with DVA and inactivate the transforming ponaple in fact it has been shown that within ose group of ·56 THE QUALITTRY OF HERIDITY dons mostards the order of the potency gunst one type cancer (Walker carcinoma) corresponds dosely to the order of thar potency to activate the transforming prinaple' One could speculate that the action of the cranosaabc drugs of this class to make the DNA of cancer cells un fit for reprodaction Obviondy this is still far from proren The second das indades chemicals (eg, analogues of natin substances) which interfere with the synthesis of cssental cell constituents. Some of them are known to in terfere with the synthesis of DNA or RNA but in general the chemicals in this class are not strong mutagens, they do not react with the audesc aad already made, and do not inacavate the transforming pracpic. The thurd class 11- clados empinaal drugs whose chemical action s mill Large ly unknown. An old dream of genetica is to induce "directed muc this would lad without waste to mutants with de arable fetares, and in omc-co new species, perhaps even to the next human species But, although ma fer cos the type of chemical reaction of the mutagen with DNA an be estimated, the actual outcome of the mutation is large ly unpredictable Somc genes are more semave to one mutigen, diffcreat genes-to another pill, one mutagen may produce all sorts of mutana. This is onderhandable when one realizes that the choice of which moleculas and which pou on the molecule of the gene are to react are largely be yond our control Mention has been made of different sa bilions of individual transforming prmaples thus in VIITO specified geres may become deliberately destroyed where others rentam 1CTIC However the corresponding THU tation on oltro has not yet been achieved As to the copen meno H DIDO 1 anggestion las been made to make the mona gemic tction more speafic by focusing the ultraviokt rays on a procular spot of the chromosomes houtver 1 ·MUTATIOY 57 auch methods are still nother crude. Pertups most resem bling directed mutations use certem types of transforma bons known under the name of "llogenic" the trains formed cell ahibit a feature different from the one amed by the transforming panaple applied. It s u of the trung forming panciple, (DNA) upon entering the bost cell re acted with the DNA of the cell to produce 1 new DNA. The case of "Linked" characters" mentioned in the previous chapter cives se typal cammple the DNA determinmg dhe appale of type b (DNA) enters the cell carrying DNA to determine apsule « (DNA) The result si cell with two apsula, e ind be rich cell now contains a new DNA (DNA..) which are both features (1 mnd b) proarmably m one molecule. The results of ach aperimeno 10 largely predictable-herce desafication us a rected mortation. This change (DNA:+DNADNA.) cannot be accomplished by merely uning the two DNA 10 1 test tube caly the cell an do it. For the reason many Xenities shudder to all it a mutugon they prefer to resc the term "crosong-over withun e molecul." Perhaps there 15 no sharp dinding ke becween these two teams In recent years, un courely different land of change in nuclac ead molecules became fearble Biochemists have been cypenunting for quite some ture with analogues, that is substances which look like the natural ones but not quite: shey may bure, for mistance, a wrong chemal group mi ngtt place of the molecule, or a righe group m a wrong place. As mentioned in the discusion of arcinostetic It me af omy Dot be out of coors to make ano sboot scother project which could become finde soon the pictorial tech aqo become candy refined. The project is to toplom In curomoot or lo fragment from any nocleus to rocha Ibe from a long congh to bclude the podle rocament, the to ploot took the (in om cc), th rould produce director bybold col por obambk by other meon The trimplantado of ober gocar punda toetaceobes, bu ready becom churred.

·58 THE CIENISTRY OF HEREDITY 5 agents, ach analogues, when properly designed, inhibit the growth of the cell, largely because they compete with the natural substances One group of such analogues, de sigried by Hitchings and Llion has a halogen (bromune, chlonne iodine or fluonne) in place of methyl (1.c. on carbon number five) of thymine, which us an exental component of DNA (Figure 4) When bacteral xrus which Deeded thymine to grow were culavated in the presence of auch analogues (especially one called bronkouracil) the DNA of the cells was found to contain up to so percent of 5-bromoural in place of thymine 4" It was as if the cells mistool s-bromoural for thymine, because of their rememblance indeed, of all these halogenated analogues, the onc best resembling thyuunc in sze (s bromoursal) was also the one wluch fooled the cell most caly Alarcover bacteriophage grown on such cells also contained s bromouraal in place of thymune Such cells or bacteriophage particles remained alive moreover they non contained 2 high proportion of mutants which persisted even when the organions were subsequently grown on noma) media 1 s Bromouracil s apparently quote selective in that it like to induce some mucanons more than others' still, a large number of genes is affected Recently the incorporation of other analogikes into bac terial DVA and joto bacteral and wral RNA *. tes also been reported Thus, one can now joduce the cell to make unnatural genes yet, the directed mutations" are almost as remore ever To obtain advantageous mutoons one will has to resort to a wasteful procedure of indoang many and select the few desired all one can do is increase mutation fre quency by the use of strong mutagens or unstable genies, the former procedure (strong radiation) s now used on plants in Brookhaven Wational Laboratory ·Chapter 1 INTERSEDIARI SISTER AND CITOPLASSIC INHERITANCE As DIXCUSED in Chapter I the miermediary system car mom the orders of the genes to the ste of the final penpheral ICATION. It is obvion that this swem itself is also under gede control and an itself be considered an intereking Object of andy About thu intermediary sygen ut loou very little. The informaton crned by the synem u very complex aod therefore ott susperus chiae the system clí is complex. If the mfortation is carried by substances, they must be fur ly complex, too procenta nodesc acids or both would fic this role. If it o noclec aard, then it must be RNA because D As a rule o not found cartade of the nudeus. There are reports that something imable comes out of the nuclear manbrand into the cytoplasen " there are sxher reports thur RNA pana from the nucleus to the cytoplasın " But the endence acting the DNA in the ea of handing the order to any other substance (RNA") milloon enstant Instead, a recent years more eTeine has been devoted to the other end of the line the RNA handing the orders to the pooram. Endence , Indeed, accumulatiog to mdicare that the RNA sessential for the synthesis of proteins and Airlligent guesses are made as to how the former determine the structure of the latter it was observed long 40 that cells 5 ·60 THE CHEMITRY OF HORITY which do not produce protans (such us spermatozoa) contam very little RNA, whereas those whose main function is to produce protan (eg, glands) contain large amounts of RNA, morcover the gland cells which produce protein catermittently contain mart RNA danng the period of protem synthes than dunng the remaining penod. An m spection of Table III reveals akso that those parts of the cel which are known to be concerned with active protein synthems (MICTOsomos) contain more RNA than any other parts of the cell Recent experiments have shown that the synthesis of protein stops short of the RNA = removed by extraction, destroyed by enzyme ribonucicax or pousoned by analogues (recent review in") upon thic additon of RNA, the synthesis is resumed. It appears now that the umino ads which became activated" by a special process, can attach themselves to smaller moleculas of RNA or RNA fragments' and eventually give rise to e protein, it : there that the information reading in the sequence of nucleoudcs of RNA is believed to be translated into the mformation reading in the sequence of aduno rads of the protein. The reverse process, the synthesis of RNA co also take place in this sy#cm The whole gruation is will fur from clear but at leas a begirung neurs to have been ode. Since the ate of the intermediary system in many casos in the cytoplasın, it ss fitting to discuss here the problem of cytoplomoc oberitance From the previous discussion one may get in mprapon that in the cell the self-determunmg particles, the genes, most roade excluarely in the nucleus. This impression ro sults from the study of the precise mechanism of coll di vigon which assumes that ach daughter cell receives one of cach highly specialized nudar paracle, the chromo some. No mechanis sammg an even duenbmon ní cy ·INDUSCLAXY GYETENI A CITOPLASSIC INHEUTAXCE 61 toplandic particles upon cell diston ha ever been dis covered thes, one argues, the cytoplasm cannot determine Excredity because upon each dirosion the daughter cells would be acqually wodowed with heredity and cvalution would be then. But, if one comes to think of it, chats for highet oogamers has sxver been adequately proven. The many getky are known beyond any doubt to be carried by chroomsonnes. But every higher organism inherits the cadre cytoplasm of the SE Is thu and other cytoplams Cruirtly devoid of genes? The problem of the gener m the cytoplast, the so called cytogenes of plasmagenes occupied de sczentists for s long LIDTX. The problem goes back to the doscovery of a ritun more phanxenon of materia beritance the inherance of certam features from the mother and cor from the fath The state of the race of the direction of shell cmilang mi pod make us a camcal example (review in) Could chert Bor be a great oumber af mich features wuch we in fest in the egg from the station only ruch * the Eurzy mauc starting dowry słucto determines the embryonic de velopencat, makrog un man and not sat Systems which are hudden because they are so obriosss thar we take them for granted? There could be, But the endence to date other refutes the Xhos or cryols that only few fetards are crned by cytoplasmic gentes beneden, even these are not inde perckemu borare controlled by nuclear genas. In the cut of mbcrtance of the direction of caling in mals, the ferrare ouhented from the mother however st » decernabed by tal chromosoma happens that the formation e lud dona even before the eye o feralsed mo that the conanbarson of the father will be felt only in the sicut geeition. The best cake for cytoplastruc mhencance would be of ooc could find in the cytoplason SOTTK port of Senes. It ·61 TO CHEMISTRY OF HEREDITY 1 self-determming xlf reproduang partides, like those in the chromosomes. For a while it was thought that much were found in the case of the Kappa particle in the proto zoon Parmenian (review in ') those cells which are "in fected by these mysterious parucles are able to produce substance that an all some other cells. The partides were ularnately under the influence of the chromosomal getes, still, the paracles could be called self-reproducing because they were not lost after many cell ditzeons and because the nuclar gene could not make them unless at least onc par acle was present. However it wou soon discovered that these cytoplotnic particles contained DNA and were ac onlly ricketta lilc invaders. The proponents of the cy toplesruc inheritance maintain that it is merely a matter of fernanac whether the particles are aled an invader (u hich implios 1 different species, rickettsa or virus) or a non-obligatory component of the cell “ perhaps pomoc day e comparison between the DNA composition of the partides and the host will settle the argument The phenomenon of the matemal inhentinct of sensor in to carbon dioxide in Drosopbild also belongs to this Category ach mhentance was found to be due to a virus carried by the egg cytoplesn. But the cases of inheritance of the plasads in plano (revica in ') cannot be shaken off so casily Plastids are integral parts of the plant cells al though under nuclar control plastids are endowed with the power of self reproduction in the cytoplase the hereditary defects in placids are transmitted almost arcu ovely on the maternal line once as a rule the male pollen does not arry them. Many cytoplasmic paracles contain RNA, it s cempong to speculate that this RNA s the self reproducing cytoplomac information-ame Perhaps the most interesting experiments are those that 1o volve transplanation of nucle i emocla (review m) ·INTERNEDLARI SYUTLAI & CYTOPLASMUC INHERITANCI 63 and hybridization a certain plants - thi the maternal" cytoplaan changed somewhat the information canned by the paternal" nucleus and continued to do so for countless generations since there o no sgn of dilution of the 12 tertial information, some self reproducing cytopleomc par tides am be suspected again. The concept of cytoplasmac nautants has also been intro duced. The cytoplastic mutants would differ from the normal truclar or chromosomal ones in that the farmer are not subject to Miendelian segregation. Actual cases have been reported by Ephrus in yeast + and by Alitchell in the mold Neurosport In the case of yeart it was found that the cells which normally forin large colonias on an appropriate tager medium, in about i per cent of the comes may for only small colonies ( petite ) This growth in hibicon was eventually tried to the lack of cytochrona od b in such a petite frun. The peates always reproduced us petites" come sort of hereditary process was obviously involved. But it was not an ordinary nuclcar heredity For one thing tho mutants did noc obey Alendel. laws they did not segregate in copected radio in abse qutat generations. For another thing the motagont were completely irreversible nrc phenomenon indicating tho complete loss of some factor By sudying the pedigrees of normal and peates, Ephrust came to the conclusion that one deals here with relf reproduang cytoplasmic particles whore praxence determine the normal production of cytochromes. The paracles con become irreversbly low by a cytoplanuc mutation which an be her pondancow or induced by a cytoplonde dagen (wch o achflavine) in both si petre Rraun ulos. One most prea that the cytochrome production, like everything else, B also onder the control of ordinary nuclear genes, in fact, one can The cytochrome yon barell for the truon of the cell.

·THE CHENUSTY OF HOEDITI 64 get "petite" by a normal reversible mutason of the nuclear genes. However the cells which hart nuclar genes to produce normal cytochromes, are unable to do so unless at least one self-reproducing cytoplasmic paracle us present An analogous attaion contes in Neurospora (cytoplastruc mutant "poky" which also lacks cytochromes i ind b) In summary inhentance by self reproducing cytoplas mic parada cuests beyond doubt. Why then, does one suspect that most essential hereditary information cannot be camed by these parades? The "peare" fumishas a par mal auster of the cell divides much faster than the particles ure reproducing some of the daughter cells may and up having no partico-a defective peace“ results thes, us discussed abore, u due to the fact that the cytoplasma Lach the apparatus for the precise transmisaon of heredin (chromosomes) One aspects that heredinu a whole could not be as orderly us it s if it depended mostly on the mreliable cytoplanac inheritance. But, obviously orach more research is necded to transform thus suspicion into macnuific truth ·Chaptor VI THE PERIPHERAL REACTIONS In the previous chapters we have discussed the first syrtam, the heredity determinants, which are the orders," tod the recoad, mtermediary synem which cuma these or ders to the given location in the cell (Figure 7) We mentioned that certain paracles m this second system may Enjoy some Imuted local autonomy they may self reprodoce (cytoplasmic inbentace) while congmtly ander the مه FN 7 Time of rec nemutton to the peripheral to N- Rocky CH--coronarocx Ses put for aplondon 65 ·66 THE CHENIESTRY OF HEREDM watchful суе of the noclear heredity determinants. In this chapter we shall discuss the third system the peripheral reaction which are the final effect of these order-giving" and order-arrying cvents, As mentioned in Chapter 1, the scope of this subject is almost as vast as the entire biochemistry of the cell, for ev erything in the cell as the result of heredity lo this chapter we shall only mention a fer characteristic exuoples. The general scheme of typical events represented schamancally m Figure 7 The thurd system, may for in rance, consist of e sequence of racons to change substence A to B to C and to D the final product D is either ualized by the cell or secreted, o 1 glandular secreton, a vaste etc As a rule, cach of these reactions can occur only of a speafic enzyme es present thus, one (favored) way the gene ap control every step in the peripheral system is to allon brut or prohibit the production of the particular enzyme. It o not the only way of course. Instead of en zymes, the change may effect the co-factors, so called cochyres which are the same for several enzymes, or the general conditions auch ® pH Entre sets of conditions may be changed by a angle gene mutation and thus affect * great many peripheral reactions at once. To this belong gross morphological danges the bloclang of permeability of the cell membrane towards nutrients or cIcrction prod ucts etc. A bacterium Eschericbu coli serves as an cxample of the baer block it may possess the CIZYTX to utilize ait ratc as the only carbon source but as a rule it cannot do so because the bacterial membrane is impermeable to attrate (review in ) it does possess the enzyme Lactose to for merit Lactose but certain strains cannot conanue the fer mentation because the bacterial membrane o impermeable to lactose. Eventually all the changes of morphology or permeabilitı will be probably traced to changes in my ·THE YETUPRERAL ACTIONS 67 C actiy hovere for the curre being ve amot study them u converently # we can the simple enzymatic reactors. Let us then go back to Figure 7 Figure 7 depicts also chromosomal geniet affecting the undindual enzymaac rections. For ampliary they are ar ranged in the stromosome in the use sequence as the co zyouacxc reactions controlled by them. But, one may thunha I would be too nare to assume that nature will follow the surplaty of the illustrator Too unei At least two cases were found here thus supliaty w followed The cases were the known 743Ction lading to the synthem of tryp. toptane or histidine, the tivo esential mano tads (trviety in") When the sequences of the correspondrag genes in the chromosomes were determined by trainduction analy 1, these sequences there found to be the same as the known querces of enzymate reactions controlled by theru (re new m) One cannot be sure why thu is so but onc fects that theres a logical beauty in this natural mochaarsın. As mentioned throughout this book all three syhteis are subject to disturbance Obviously the syetemes are a etc #heefver healthy or asling & self reproducing gerse molecule ou chemical reality whether it 3 x "normal (60 called ald) or a mutant gene Buc ses casest to nouce the premsor of a geixe or syatem which was taken for grant ed, when it changes or fals. Thus the bulk of our Loxon edge about the three systems Cort from the audas re lated to mutant genes whuch (nl to perform the "romal” functsons. The effects of auch gerne falures upon the thurd (peripheral) systed ut known # geurac blocks Conader for instance a mutabon, in włuch the gene controlling the enzymatic resco (* D (Figure 7) mutata ro id leche yariety (allele) the corresponding cat Tyme till not be pr duced and the reaction between Cand ·68 THE CHEIDTRY OF HEREDIT D will be blocked The consequences of this Hock for the cel depend upon many factors. The product D rught be of fome mall ogruficance n patun selection (eg, some unuportant pigment) in that case the mutent tod the from it angidates may survive without this product for a long time. On the other hand, the product D may be esien tal for the life of the cell, us in the case of an anno sad or 1 vitumn. In such a ghidon it is said that the cell has ac qured me absolute requarement for the metabolite D The cell can still live provided the metabolite D u sopplied and can reach the made of the cell. It may also happen that the reaction CD is blocked not completely but partially some of the product Dis manufactured, but not enough of it Such cix is referred to a partial requirement und auch macant, on laboratory rangon, s called a lenky noten Bur poppose that in a mutat which has an absolute require ment for substance D this abstence annot be supplied, or if applicd, cannot reach the meeror of the cell. In the cases, the cell will die. It is one example of a letbd Nation The example of the sequence of enzymapc reactions 15 represenred in Figure 7 1 I very ample one. Alore often than not, the reactions are likely to pursue a venable maze with by passat, adc entrinces and cats, and traps, us se gented by an imaginary cumple shown on Figure 8 to make things worse (for a samost) some steps may be re versible and come Dot, some slow and some fost come end produca may mahibit the activity of the preceding enzymacs (so called feed-back Control) so that not too much of the end product be made, etc. All these things complicare thic sudy For example, 1 fcientist will produce 1 block between D and E hoping that this will result in an absolute requirement for E, to hos dismay the cell may outothom by Aarting to manufacture E through by pass BF-G ·THE PEUPHERAL REACTIONS 69 E This by-pass mechanison might have been produced only u thus particular moment, by the use of so-called adaptive enzymes, or it mght have been there all the amc, although normally not med One must not forget that the cell, Hoogh most economical, also believes in incorance and s prepared to meet all sort of emergencies. A Co F---> H Fr. I. An example of compla metabolic pechwy (5o. ht for a planation ) Conader another cxample A strast notices that after a certam mutation the cell starts to manufacture product II which it did not manufacture before. One may think that & new enzyme to make it has been produced by the motertion. Actually the wory may be entirely different Suppose that the reaction |-- K occurred so much faster than + Al that normally all of I requintioned and there 10 chance of it ever going to M Bat of a mucation prodaca . block between I and then I will now be available ·70 THE CHEMISTRY OF HEREDMI for converson to A1 and 1 deceiving atuagon rerulos. Two other decering cases, where the inability to uulze atrate or to ferment lactose was due to the fault of per meability and not to the lack of enzymes, were mendoned previously Despite these difficultas, the genetic blocla proved most useful for the unraveling of pathways of synthesis in the living syntes (repicued in ") The organisms most used Here the mold Neurospora (Beadlc, Tatum and others) and bacteria (Dans Lederberg * Ryon and others) hou cver there a little doubt that the information guined here is in most cases applicable also co higtier orginni, jocłud ing man. One cxample of the reasoning used in such a study will be explained below with reference to 1 ample schierte shown on Figure 7 (review in ") Let us Loume that the sequence A+ BC-D is unknown, all ooc knows is that A as somehow converted into D Onc produces (48 by irradation) several different mutants which cannot manufacture D but can live of the latter o supplied. One of sxh mutant may accumolate & hitherto unkou abstance C if given thus sulistance, the mutant cannot utilize it to make D The aspicion is that G in mtermeduste in the synthesis of D (a precursor of D) the substance Cacumulares because a Lecps on being manufactured by the cell but cannot be remored by couver pon to D the block in this mutant is then, most likely beruten C and D Another mutant may accumulare not C but A DCT substance Bit cannot make Di B given but can make it if C is supplied. This ponts to B as an inter mediate before the block is now only between B and C By this pamstaking research many synthetic pathways have been confied and many hitherto unsuspected inter dobe pabr 1911 ·THE PDIPHERAL REACTION) 71 medutes discovered. It goes without saying that this knowledge u of utmost importance, not only for the basic unden trading of the charmury of life but also for many practical purposes the lookedge of the steps in matural synthes lads to logrcd rather than campiocal, deegnrog of means to interfere with them (analogues arcinostatic agents) or to remedy then, if deficient. An nesthetic ex ample of ach a pathway is illustrated on Figure 9 (brosyo thenus of threonine and methonine.) - CYIT ME CIT TONE HOMOCYOTE NE- ETHION E ++ HOWOTE C THRONNE Fm 9 Boryntheds of threonbe od masonice (from 15) In the above descrison it was tocady implied that the mutaton of one gene con abolish only the action of one enzyme. Is this necesanly so? It x, accordmg to the soalled one-gene-one-enzyme by porbess (rtview in") The proponents of the hypotheus quote nu Tous copies of one geno producing (or failing to produce) only one en zyme. The hypothesis wus very attractive and therefore * promptly attacked by other factists who were eager to pomt oot cramples to the contrary pucho one motition abolshmg two of more crazymac reactions at once. One mitation, for oumple, con abolist the synthesis of both threonine and prettionine. "Thes-the proponents reply--- merely due to the compleuty of the storation. Just take one look at Figure 9 tgum. obnously a mutton blocking one enzyme producong homosering, will result in the fulure to male borb threonine and acthuanine. The for the proponco were able to use all the cos of cocon, a cept the one that this for the term gETHe" stself is not well defined from the biochemical point of thew ·DeT" 71 THE CHEMISTRY OF JEREDITY In all of the above discussion, the mutations mentioned frequently were the loss mutations some ability which the wild grunn had, becue loss The question frequently asked : Are all mutations loss mutations? If they are, how can mutadons be the source of raw matenal for evolution The biochemig s anstrer to the first question as the usual one we dont know A mutation may appear to be 1 GHR motagon, such as again in an enzyme or in a "new" mets bolic pathway actually is we have discussed abors, thus enzyme or pathway might have been there all the ame but wo mhibited or inactive: it mght become score by a loss of inhibitor a block in a normal pathway or in a ade-esit. One must not forget that a new functional en zymc requres 2 new pery specific and complex anit of genetic inform and an injury to a genc ss more likely to destroy a unit of information than to create one from nothing The last word on this important subject has not yet been mid however one must repeat, any proof of the nctdess or gun s going to be difficult This field of sacco u at bext fifty years old, but the history of any peces probably more than a hundred thousand aan one guarmtee that what we regard os appeanog new has not been stored in the genetic memory of the speas? More an be mad about the second question how can los mutations be the source of my matemal for evolution? The mutation may result in a loss, but the degree of hart may be so small that the stron may purvive for quite : while. In the meantime the conditions may change so that the lost abstance is no longer necessary this would make the mutant us good us the wild strun. Or even better In many cases one could demonstrate (in bactena) that in the presence of the metabolite m the medium the motiot which lost the power to manofacture this metabolite out grows the wild gram which can happfacturc it. This ·TBI PERIPHELAL REACTIONS 73 sectmngly parsdoncal studion may occur because the wild ar pill keeps on manufacturing the metabolite, bus wirtung those and energy on an unnecessary synthetic proces on the other hand, the "handicapped" mutant amply take the ready metabolite froun the medium. Sotee scientia behere that this is how parase species (requiring very compla media) cunc mto custence anch spears have lost the ability to manufacture any metabolitas bat Prvive very well because in the course of evolution the hosts which supply thiese metabolites beoon readily avolable. We ourselves have lost the ability to syntbeorze many metabolites, ach o the so alled essential empo ads and some vitamins, however we do not worry about it because we are parentes on other animals and on plants Alany mommaons are reverable the process, called re DXTSE mutation or back mutation may partially or completely restore the ability lost by the fire (forward) muttoon. If one investigato the metabolic pathways restored by the reverse mutation, it will be found that in many cares such a pathwry the onginal pathway of the wild arun, nothing seems to be guned or lost by the full cycle "for wurd reverte. Bat a certain cases the mutations is not to the original but to an endrely different pathway" in such 1 case the cycle may have in evolutionary advoog. Well, myhow popuble or mpossible, cvolation occurs, and once nothing better than mutation was ever discov cred in material for evolution, we may o well accept It for the one being Bor another question u whether or not the evolucion proceeds by the dow accumulation of small motaom (micro-ondations) Whlc the majority of genetics beheves that arch the case, few vores are also hard fronung erplanteon molving co-evolution that u large geretail opbeavab (TWICTO-Mutations) wluch would change whole blocks of essential faturos at

·74
TIE CHEMISTRY OF HEREDIT
onceit. * Just how the organison could avoid biochem
al mess in ach an upheaval is not clear Howtter onc
must admit that the instabilities (high mutabilioa) of
whole blocks (if not all) of genes at once occanonally do
occurile
as mentioned in Chapter IV instabilities many
escape clmination by natural selection and may play
some rôle in evolution

·Chapter III HEREDITARY DEFECTS IN MAN* +++ IT au been mentioned in the previous chapteo that, thanks to the amilanty of ancatul metabolic pathways m organisins, many of the findings m microorgimsus spply also to man. The question of just how many will be en rwered when enough biochemical research will have been conducted on human cells in tissue culture e especally when grown m Amperson, por umlike bacterial cells But for a phyucan it 8 of more interest to conceder the organism as a whole con we under ind any of the heredi tary defects in man? We an, but thus tur only a few defecte. To be sure, many defects are known to be hereditary many of them are suspected to result from a biochermal disturbance (Table VII review in ") But in most cases we can not put our finger on the cract chemical nature of the trouble The gudies in humans are understandably dow there of the difficulty of obtuning old famuly records, hu Lo to boot the then bastery ill be in the then bom or coogenal Thu kathe two tim u broeder neto ang poc only banfary defect bor bo defap o bronk md fortal life. to enl the media of ben conoc auhurs bold pret proro for the focuft of loc real Pure Cons from pople cette cu begon od mat ddwraca bo co pridal sain darr mined Ho celebre ca bo objccted to addition to the doced chroglom sboormalo obehu Mmdoubtedly odber Dogi som bo be copied befan long 75 ·76 NIE CIEMY OF HOTY thetal com TABLE VII Hootorpaty DOTI DALY Now of DC Brocborde Son Roman Albacom Fwort to Dangfacture me kon 100 ADreptonart Future co oddize bomogodilo od 175 109 Cocinaria Abooom orcreton of cycne, lyubo, பராm ad emhhurவாவos 170, 171 Galactancia Futart to coarert gulactose-1-phot phate into plucom l-phosphorte 181 Crocher's doce Deportion of bromal DOOD! or kern m the cells of recolocado- 100 Greagtoob Accumaledion of dycogen bedre liver heut od plem 109 Gout Ekrited blood ark kod od drooo tion of sodriom barneathe DO 109 Hemolytic en (phrocytoch) Defece in giriye 179 Hmophia Atong blood chodby factor 109 Hypercbolesteralerna Dernied blood cbolesterol 109 Hypopbompheta Abatorral mineralantion of bont, di miastbed Jaune phoxparke athy created ormory for a plot portadykerholurdune 174 Lo funile arac Accuvolation of philoporelo o the bola celo 109 PakowTM Lucretion of petoke pogin to the arge 104 Pbaty Pecoourta Fallare to coore phenylbame to lytout I77 171 Porphyri Foredom of the porphyrne bote artne und focos (7) Spordic crembo Defecture synthes of thyroid hor vah rotter 2006 10 Tyroketonur Fullore to coorert p-hydroxyphenyl pyrarle od foto 25-dihydroxyphe oylpyturke od 100 Vi de Delected copper metabolic 172 لكز ·HOODITANY DIFICIO IN MAN 77 man reproductions dow and, above all, there is the diffi culty of a permenung path living human trae. In the few cases which we do understand the disturbances turned out to be emple geocac blocks aused by mutations, JUR 1 the ones that occur in microorganisons described in the previous chapter These cases are deseed below The best understood bloco in man concern the metabo lign of the umino sad phenylalanine. In the normal cours of events, the ances of phenylalanine from the diet o converted into tyrosine come of the latter i utilized u such and the exceo is cleanged aloog two metabolic pathways (Figure 10) In one of these pathways tyrosine u converted by the enzyme tyroanas into 34-dihydroxy phenylalanine (called DOPA) and then by a sents of re action-mto the pigment melmoin Now some rare individ cals, the dbaos are unable to produce pigment-1 striking defiacacy arly recognized os hereditary defect. Upon do ser investigation it wo found that the albinos back the entzyme tyroanzsc. Onc usumes that, in the cases studied in MLETOOTGOINTA, one deals here with 1 omple geneuc block (A on Figure to) due to a mutton. In the second of the metabolic pathways, the excen ty ROADC u normally converted into p-bydroxyphenylpyruvic aad, then to 2 5-dihydroxyphenylpyruvic iad and then to homogenhoc tad ( kupton) which eventually de tabolized to CO, md water (Figure 10) However in some mit indhviduals the homogeotac iad o not further inctubo lized od Barcreta u much in the urine the latter on standing turns black due to the ondation of homogentiac sad In later life, the patimu may also develop black PAS mentation of the artilage (ochrono) probably also due to the ondaton of honogentiac iad The disease was recognized s being hereditary (1 omple recetive gene) by the brilliant work of Garrod who is also the first ·PROTEINS THOX.ME ADRENAUME & MORADRENALINE OH OH HO [IMTE VEDUTOS) Nitz FH CHD the A хне-сн WH2- 2- COOH COOH COOH Pney! He 34 Dikto At hul (DOA) CE C-0 с о COOH COOH prrei nho OH C-0 COOH 2,5-Dihydropbypy mi ald YOH HO CH COOH Fr 10, Gepetic blocks in the metabolic pathwry of phonylalandos ad rytorne (from H) Blocts A-AL bhnbm, B-Vlaptonord. C -Tyroletooars, D-Pbc mintonut. nuo CO2 + Hp ·HEREDITARY DEFECTS IN ALAN of normal persons 79 to develop the concept of the mbotn errors of Hotuba- Lsm The diserte wu called dkeptomu, it was the fire brochemical motme recognized as such. The inability to metabolize homogentiac aad was eventually tried to the fact that the leaptopunes actually lack the czyme homogenoac iad andare whuch * prosent in the blood 1gun, we are dealmg here with a amplo geneuc block (B on Figure 10) duc to a mutation A discute alled troketonuria s charactenzed by the a cretion of large unount of phydroxyphenylpyruvic aad. The discreto nire that one cannot cven be ture that it is hereditary One suspects that the block prevents the con vernion of p-hydroxyphenylpyruvic aad to a 5-dihyroxy phenylpyrıvı iad (C on Figure 10) Returmog to the discussion of phenylalaninc, onc notices that tho cicon of this amino ad an also be converted into phenylpyruvic aad. Normally this product does not appear in the urine it does, however 10 certain patients, who grungely enough, are also mentally deficient. The disease pbenylketonur, wu found to be hereditary (e angle re Comave gene) The connection with the mental deficiency u all not clear but the biochemical ade us caper to comprehend it wu noticed that phenylalanine itself pales op in the blood of the parents abo they are often albino These two facts iodicate that the block 13 between phenylalanine and tytoane (Don Figure 10) the increased level of phenylalanine resula then m the appearance of phenyl Pyruvic ked to the unne It is of great interest to Doce that the condition of mental deficiency could be and has been allevated by limiting the annount of phenylalanine in the diet (review mn)-1 tangible dividend from chiemial genetics Another mportant and well worked out metabolic path *** n chat of glycolyes, the macrobic breakdown of glu ·80 THI CHEAISTRY OF TERIT cosc. In group of hereditary docere alled congenital benzolyuc acme glycolyus in red blood cells has been found defective (review in") A detailed sady pamts again to a simple gencac block the enzyme mvalved secus to be acher enobase which convert a phosphoglycerate to phosphocnolpyruvate, or the phosphofructokinase which convert fructose-phosphate mco fructose-1 6-desphos phate. Sporadic ctetrista atb goiter appears to be a hereditary dosease caused by the arrest at any stage of the synthesis of the thyroid hormone (revia m' Three mechan Lims have been xudied In one, the block due to a lack of che andative CTLZYTe causes a faure in such indırdoals to prodace mono- und duodotyrosinc from iodide and tyrosyl readacs. In another mechanum, the duodoyroane nialeculas foto couple with suffiacot speed into thyroone. presumably dac to the failure of the coupling enzyme. The thurd mechanign deals with the catabolism of the above mentioned precursora mono- and duodotyrosinc. During che process of thyroglobulin degradation the above pre CUTTON escape from the thyrad gland into the blood and pommally are rapodly deodinated by the enzyme jodony roanc deshalogenise whereby the rodme os made available for reutilization. If the enzyme fails (due to a genetic block) the rodinated precursos escape to the anne and a know jodine deficency may result. Galactonetta 13 hereditary disease characterised by a fallare in the metabolism of galactose (review m) la the normal metabolic pathway galactose s fire con verted by means of adenosne triphosphate (ATP) into galactose iphosphate the latter by means of undine diphosphate glucose (UDPG) i converted into glucose Iphosphate whuch corers is such to the normal pachny of utilization of glucose. The enzyme idoled in the la ·TANY DETI IN MAN BI rector, Pagalactose-ondyl trandararse was found to be lacking to the crythmytes and the livers of galactoveone peper Thux gencac block remulo m an accomala chom of galactose phosphate wtuch kennt to produce tisoc dainage and growth inhiburon The excluon of galactose should prevent accumulation of galactose ? phosphate it was found that lodeed the gulsatowe free diet prodoces e reversal and, oftere, complete ciesrance of all symptoms, with rekordon of normal health In all the above connderators we referred to the "fail one of the cixyme" or "lack of the entyme." However the lack of the enzyme does not necessanly mean that the soolecule of the enzyme (or of de protein in general) Tessing altogether it may aften mean that it is defective Le chunged so as to be partually or totally inactive. Jug bow much has to be cuanged to cause inactiviboa? Whar the anallen change in the protein which the matroon has to product to make itself drastically felt Ooc cxample of the answer to these questions fuas been provided by a audy of a beredrary discis called ockle cell me The doresti, cured by : ongle mutant gene, characterized by the prescoce of defective erythrocytes which are in the forn of ackles. The defect tu traced to defecare hemoglobm and the problem was to determine what is the characal stature of the difference between dus defective and the normal hemogloben. Pruling sod has collegica subjected to two kinds of hemoglobin to electrophores and found thar the rumo bure different clectric carga" This behavior suggered some diffeunde in the amino aad compondon. But how many were different? And which one? A molecule of hemoglobin hus me 600 SUUSSO tads, of 10 different kishin and the problem sought have appeared hopeles. It wu polved eight years later by Ingram who broke the wok ·82 THE CHEMISTRY OF HEIDITY cule in half and then into 29 smaller fagment (popada) When such fragments from normal hemoglobin were compared with the corresponding fragments from the defective hemoglobin, all were identical, cacept one And in this fraginent, all amino ads were identical except one Thus the disease was awed by a change of one amino ad in 300 (glutamic aad replaced by voline) This is all the mutation had to do to make itself senowly felt. One is cempted to speculate that the corresponding change in the hereditary determinant (DNA molecule) was just a shall perlaps it as a change in a coglc auccoude. An des B a mere beginning But the beginnmg bas been made. And onc us inclined to agrec with Albert Einsten" that the most incomprehenable thing about nature u that comprehensable ICBS ·APOLOGY The writer feels that he owes several spalogies. First, an apology to the reader For the book being so long yet fulmg to offer real mswers to many formulated qucae. The writers excuse is that the subject as but an infant, if we have become able to ask nature embarasang questions, it is already 2 crack in the wall. And an apology for the book beng to short. The disciELON of many heredt tary dosesses and of the cancer field has been ormatted, partially because these subjects belong to special treatises, and partially become thar connection with the chanistry of heredity is merely the object of future study The water also owes un apology to the saenusts whose pangalang research he had no chance to describe in a book of thu se. The reader can be counted upon to reale that in the background of every spectacular achievement there are handreds of publications whuch prepare the soil. But there a will another apology i more gruve one ani apology for the attempos, by all chenscal geneticas, to tamaper with outure s srost closely garded secrets. A con trol, at will, of the heredity of virulent microorgasms and of mo may result from these atempts Like the release of stormic energy the control of heredity may be oulzed for the toul destruction or for the benefit of our spece. B3

·No text on this page.

·BIBLIOGRAPHY 1 Avery O T MacL cod, C A1 and McCarty A1 Studies on the chemaal mature of the cubeuce inducing transfor mation of pneumococcal types | Erpet Med 79 137 1944 2. Himmarting J Ober fornbildende Substanzen bel Ace tabularia mediterradet, ihre rumliche und zeitliche Ver teilung und ihre Herkunft. Arcb Ext Alecb 131 1 1934 3 Bracbet, J and Chantrenac, H Proton synthew in nucle Ited cod non-nucleuted halves of Acetabularia mediter ronea audied with arboo-14 dionde. Neuro 169 950, 1951 4 Vanderhaeghs F La effets de 1 enucleation sur le synthese da protéines chez Acetabularis datorrent Blo cbtom. Biopbys Acte, 15 281 1954 5 Northrop J H, kuputz, VI and Hammott, R M Crystal Une Enzymes New York, Columbua Univ Press, 1948 6 Mendel, G Versucbe uber Pflanzuby briden. English translation Cunbndg, Harvard, 1948 7 Lyxenko TD Sopust Blolop A report to tbe Lost Mademy of Agricolara Sclences foscor London, Birch Books, Ltd., 1948 8 Goldschmdt, R. Pbysiologica Genetics New York, Alc Gry HI, 1938 9 Dobahansky Th Position effect of gens BioL Revers 11 364 1936 10 Dobak Th Genetics and the Origre of Specles New York, Columbia Unver Press, 1941 1953 85 ·86 THE CHENILSTRI OF HCREDIT 11 Taylor J H Hoock, P S and Hughes, W L The or guruzation and dupliadon of chromosomes es reruled by autoradiographic gadies using mom-labeled thyrndine. Proc Vat Acad Sci 43 122 1957 12 Gnffith, F The Agnificance of percumococal tipes ] Hy! 27 11) 1928 13 Dawson, VI H and SA, R. HP In tro transformation of pneumococcal npe ) Esper Vled 681 1931 14 Alloa'u JLThe transformation in hitro of R pacu mococa into S form of different speafic types by the ux of filtered pneumococcus atracte ) Erper lled., 55 91 1932 15 Alionay L Further observations on the use of pret mococcus extricos en effecting tusfomandon of pe ritro. Espet Ifed 57 65 1933 16. Alexander HE and Lady G Trunsformation type spe aficity of Hofher de Proc Soc Esper BLOL & Med 73 485 1950 17 Zamenhof S. Biology and biophysical properties of transformang paraples Progress # Blopdracs AS 1916 (Pergamon Press, London) 18. Zamenhof S. Properties of the transforming principle 10 The Chemical Beds of Heredhty (Edited by HD llc Elrou and B Glas) 351 Baltimore, John Hopline Presh, 1957 19 Spizzen, ) Transformaton of biochemically deficent Rruins of Bacillus fubtilis by deoritibonuclare. Proc Vat Acad Sci H 1072 1958 20 Sarith, E E B., Vulk, GT Bemheimer HP und Aus tran, R. The formaton of undinc pyrophosphoglucuronfc acid from undine pitophosphoglucose by aracts of a noncapsulated strun of pneumococcus. Biocbim Biophys Ada 21 211 1958 21 Smith E E B., Vis, GT Bernheimer HP und Aumun R The presence of an uronic red cplmerate in a grun of pacumocnctus nipe I Biocbow Blopbys det 2-640 1957 ·BIOLOGIAPHT 87 22 Horchhta, R.D Transfer of peniallin restance in pact mococa by the deon, ribonuclate drived from feest cultura Cold Sprms Habor Symp Quot Bioh, 16 457 1951 23 Lederberg J Lederberg Edi Tioder Dund Lirely E R Recambioztion imly of bacterial heredity Cold Sprang Harbor Symp. Qout Biol, 16 413 1951 24 Zinder N D and Lederberg J Genetic change in Sat monch.) Bact 64 679 1952. 5 Zinder ND Infectire beredery in bacteria. Cold Sprg Harbor Synp Qunt Blol 11 261 1953 26. Hersha A D eod Chase, AL Independent functions of vimal protelo and nuclex add in groad of bacteriophage. I Gex Pbystal 36 19 1952. 27 Free D A Lahler H R Shug A L. and Thoma, CA The Infection of sub-cellular Excherichia coli, Arun B, with D preparation from T2 bactenopłage. Proc Nat And Sa3 930 1957 2B Sunkes W AL. Isolation of crystalline protein posseung the properties of tobacco-mosaic nu Science Il 044 1975 29 Frucnlcl-Coruna, Haod Williams, RG Reconstitution of actre tobacco mosaic virus from 10 inactive protein and muclerc cod componenta Proc Na Acad Sal 41 690, 1955 30. Lppen.cott, J A and Commomoner B Ractriton of robucco mouse virus infectivity in murtures of vine protein und nucleic acid, Biocbrm Biopbys Aero 1 198 1956 31 Fraenkel-Court, H, Singer B A and Whans, R C The nature of the progeny of virus recondituted from proten mod nucleic acid of different struins of tobacco Dosic viros, m Tk Cbroded Bans of Heredity (Edited by H D Alc Elros md B. Gb) Sou Balamore, Johors Hopkins Press 1957 12 Gieser A and Schrum, Glofectivity of ribonucleic od from tobacco mosaic res, Name 17 701 1986 ·88 THE CHEMISTRY OF HEREDIT 33 Frenkel-Connit, H The role of the nuclac sad m the reconstitution of active tobacco-mnogic viros 1 AN Cam Sợc, 78 882 1956, 34 Stanley Wal Relationships, established and prospective between proses und ancer Amm. New York Acad Sci 11 1100 1958. 35 Colter J S., Bird, H H and Brown, R A. Infecurity of ribonuclec acid from Ehrlich ascites tumor cells infected with Alerigo encephalitis, Nature 179 859 1957 16 Colter J S., Bird, H H Moyes A. Jy wd Brown RA Infectivity of nibonuclac scd isolated from vino-iofected tistes. Vrology + 522 1957 17 Alexander H E, hoch, G Alorgen llountain, L and 1 an Damne, o Infectivity of abonucleic acid from pollo virus in human cell monolayers.) Erper Aled 106 493 1958 38 Wecker E and Schafer il Eine infektione homponente von Ribonuclandure-Chancter aus dem Virtis der men kanischen Pferde Encephalomyelids (Typ Ost) 2. Natur forsch 12b 415 1957 39 Benoit, J Leroy P Vendrels C ind i endrely R. Do mutations somatiques dengtes sont-ellos porsblos chez les Olon CR Acad Sci 244 2321 1957 40 Thorell, B Nucleic acids in chromosomas und mitotic dr rigon, In The Nucleic Acids (Edited by E Chargaff mod JN Davudson) 2 181 (cu York, Academic Pron) 1955 41 Zamenhof S. Newer aspects of the chemistry of nucleic Hads, in Pbospbotus vetabolism (Edited by IV D VIcEl roy and D. Glass) 2 301 Belamore, Johns Hopkins Press, 1952 42 Wyatt, G R. and Cohen, S.S... Nuclerc rads of nchcture, Nature 170 876 195. 43 yut, G R and Cohen, SS. The bases of the nuclec nards of some bacterial tod animal truses. the occurenc of s hydromethyl-cztosinc. Blocben SS 774 1953 # Daly Al Alirsky A E. and Rx H The unito trid ·89 DIBLIOGRAPHY composition and come properties of histones. J Gen. Pby Sol, 34 439 1951 45 Alfert, A1 Cherbal dhfferentiation of mudar proteins during spermatogenees in the almon | Blopbys Bio cben. Cytol, 2 109 1956. +6. Vendrely Ry koobloch, A and I cadrely C At et tempt of pang biochemical methods for cytochemtaal problems. The deoxyribonucleoprotein of spermatogenetic cells of boll testos. Esper Cell Resercb Suppl. 4 279 1957 47 Vendrely R. and I cadrely C La teneur du notu cellabuire en mode désoryribonuclique i travers les organa, les individus et les coplcas mimales. Esperientia 5 327 1919 48. Aliruh A E and Rus, H.. The deputyribonuclec nad content of smal cells and its cvołucony wgnifiance. I Gen. Pbystol. 34 451 1951 49 Holender A. und Emmons, CW Wavelengths de pendence of mutation production in the ultranolet with specul emploss on fungi. Cold Spring Harbor Symp Qncor Biol. 9 179 1941 50. Zelle, M R Ogg J E and Hollander A. Photorectution of induced mutation and motivation of Escbericbu coB composed to nodion wire lengths of monochrommt ultraviolet ntdutson J Bact., 75 190, 1958 51 Schrader WC Phosphorus compormda in kumal tis. suas J Biol Cberx 161 291 1915 32. Schneider W C, Hogeboom, G H od Rom, H E INmcellular distribution of enzyTDA VIL The distribution of nudae words and densornetnphosphatase 10 Domnul mouse liver and mouse bepatome. J No Cancer Iust 10-977 1950 53 Johnson, R. V md Albert, S. Lacorponton of photo the phosphoprotein fraction of mammalmo tisic J Blol. Cbera, 200-355 1953 54 Wyntt, GR kod Cohen, S. S... The base of the nocleic sands of poke bacterial od trimml siru the occurrence of 5-hydroxmethykytosuna. Biochem. I ss 774 1953 ·THE CHEMISTRY OF HEREDITI SS Tatt, G R Recogniaon and estimation of S-methyl cytosne in nuclac iads. Blocbera ), 41 581 1951 56 Dunn, D B und Smith, JD The occurrence of 6-meth hornopunde in deorytibonucleic acids. Brocbent , 68 677 1958 57 Adler 11 Wasmann, B and Guthen, A A. Occurence of methy Lored punne beses in tast nbonuclerc nad J Biol. Chem., 230 71, 1958 58 Uttlefield, J W und Dunn, D B Natunl occurrence of thymide and three methylated denne beses in several ribonuclac aads. Nattore 181 254 1958 59 Levens, PA and Bas, L. W Nucleic Acids New York Chemical Coalog 1931 60. Lehunann-Echternacht, H Ober Oligonucleodde aus Thy mno-teclanstare Zs Physical Cbene, 269 187 1941 81 Gulund, J AL The Aructure of nucleic acids. Cold Spring Hobor Symp Quot Blol., 12 95 1947 62 Chergaff E Chemial specifiaty of nucleic ads and mechankan of their enzymatic degradation. Experienti 6201 1950 63 Zaunenhof S. and Chargeff E Dosymetry in nuckoode sequence of desory pentose nuclerc reds 1 Biol Chem., in 1 1950. 64 Shapiro, H S and Chargeff L Studies on the nucleodde arrangement in deotynbonuclec iad. Biocbitor Blopbys Act 26 596, 608 1957 05 Elson, D Treat, L W und Chargeff L The nucleoude composition of pentose nucletc eads in different cellular fractions Biocbome Biopbys Acu 17 362 1955 66 Cohen, S. S. and Stanley 1L The molecular size und shape of the nucleic acid of robecco mosaic rinn / Biol Cben IH 589 1942 67 Watson, JD and CacLF HC Holecobar anycture of nuclac iads Agtructure for deon nilxoge nucleic acid. Vature 171 737 1953 ·WALIOCILAPAT 91 48 Wilkin, as HF Scakes, A. R. and Won, H R lla kcube #ructure of deorypontos nucles wisds. Name 171 738 1933 69 Frmklio, R. E u Gossing R G. Violecular configure moo in xodium thymoaudeste de 171 740 1983 70 Warton, JD and Crack F HC General mplicadors of the structure of deoTyribonuclerc wad. Mature 171 961 1933 71 Chargaf E. Descris in The Cornical Bou of Hered sty (Edited bs WD AlcElroy and B. Glo) 528 Balta wone, Johns Hophuta Prew 1959 72. Delbrick, IL and Scent, GS. On the chanm of DVA Keplechon, in Tb Chemical Batus of Heredity (Edited by WD McEron and B. Gloss) 699 Delamore Jaims Hopkins Pro 1957 73 Viascio, IL and Schl, F 11 The replication of DVA is Escherichu coh. Proc Nat Acad Sci 1871 1938 74 Granberg-Ilaga, 11 md Ochos, S Enviatic stiche: att and breakdown of polynucleoudes, poły muchandic phos phony lase ) An Chem. Soc metany 3163 1955 75 Ochoa, S. and Heppel, L A Polynuclende synthen, in The Comece Basis of Heredity (Edited by ID VEros ad B Glu) 015 Balamore, Johns Hopkins Preta, 1957 76. Heppel, L. A. and Rebou is, I Enzymology of on derc acid, purus sed pyrimidine. Am Rer Brocbmw 17 613 395% 77 Singer ILF Heppel, L Awd Hime R ) Ougono cheo des « pret for polynucleotide phosphorylac Blochema Bwpby 40 26 #7 1997 78 hornberg Am. Panals of comarc entha's of nucleo tudies and poli machondas, on The Coco Bar Horeday (Edited by D licfiro od B Głm) $79 Belamare, Johns Hopkins Press, 1957 79 Solam, F) Incorporation of thymidine triphosphate Into deatyribonuclee wed by penfied as an enzyrk, I Am Com Soc 10 176, 1958 ·92 THE CHEVILSTRY OF HEREDM 80 Lehman, I R Bestman AL J Sunms, E S. and hornberg A. Enzymane synthesis of detyribonucleic acid. J Blol Cbrx 233 163 1958 81 Bestan, Al J Lehman, I R Summ, E S and Kornberg 4 Enzymatic synthesis of deoxyribonucleic acid ) Blol Chem 233 171 1958 82 Todd, A. R. The nucleotides sooc recent chemcal re search and 18 biological unplications. Horty Lecto! 1951 52 83 Michelson, A 11 Synthem of nbonucleic acid. Natate 111 303 1958 84 Khorana, H.G Razzell, 11 E. Güham, P T Tener G A1 und Poh E H Syntheses of dideorribonoclcondes. Av. Cbemy Soc 79 100., 1997 85 Khorne, H G., Teper G \1 and Alarkham, R... Cheanal synthesis of oligo-thyrudine nucleoodes and their de gradation by venom phosphodiesteras Federation Proc 17 253 1958 86 Churgaff Em Crampton, C F and Lipstica R Separation of all thyrus deori ribonuclerc tad into fractions of dif ferent composition Vaute 1 2 289 1053 87 Broat, G L and 1 105on, \ Heterogeneity of deoxy ribonoclerc nads. Naturt 172 339 1953 88 Bendich, A Fresco, J R, Rosenkram, H S and Bexer SV Fractionation of deotyribonucleic acid (DVA) by won exchange. 1 Amer Chem Soc 77 3671 1955 89 Zamenhof S., Alexander HE und Lady G Studies on the chemistry of the transforming activity Expet Hed 98 373 1953 90 Leid: G Hahn, E and Alexander H E. In vitro pro duction of ach tipes of Hemophilus influenza.) Erper lled 97 467 1953 91 Horchloss, RD and Alarmur ) Double marker trus forartions # endence of linked factors in desoryrito nucleate trunsfomning gent. Proc Væ Acad Sci 4055 1954 ·BIBLIOQLAPIT 93 92 Lerman, LS Estamation of the catcal DNA segment reqwred for genetic transformation Proc Y lm Congress Genetics 2 16+ 1956 91 Lut, ai Vurmur ) Ephruss-Taylor Had Dot P The dependence of pneumococal trusormoon on the molecular weght of deorytiboxe puçlec 1cd. Proc Nat Acad Sci #14 1958. 94 Benzer S. The elementen Urts of beredity in Tbe bevid Bons of Heredity (Edited by W D VcElroy and B. Glas) 70 Baltimore, Johns Hopkins Press, 1937 05 Ryan, F ) Spontaneous mutation in non-dividmg bac teru. Genetics 40-726, 1955 96. McElron WD and Swanson, CP The theory of rite processes and gene mutation. Que Reo Bsol 26 348 1951 97 Den erec, Al Unstable genes in Drosopbille Cold Spring Harbor Symp Quor. Biol, 145 1941 9 Zamenhof S. Studies on factors mfluencing mutability Experiends with unstable genies. Genetics f7 64 1945 99 Rhoada, A1 The genetic control of mutluty in maze Cold Spotag Harbor Sywip Quant Bol 9 138 1941 100 Goldstein, A and Smoot, J A krumn of Escherichia coli with an wusually hugh mute of totrophic mutation / Bact 70 588 1955 101 Zamenbof, S, Greer Sind DeGlorid, R Study of spontaneous gene urrsoabilization in Eschericbus coll / Bact S 510, 1958 102 Zamenhof S od DeGroninn, R. Stady of survival of onsable struid of Escbenicbus couſ Buat 75 514 1958 103 Zamenhof S. and Greer S. Hac o un agent producing tugh frequency of mundong md wwable genc in Es cbencbu cat Nature 112 681 1958 104 Timoféeff Resorky N Zimmer h. G and Det bruck, Al Ober dxe Nerar der Gentetidor und der Gerstruktur Nocbr Ges tross Gotthagen Hab-Pby Al 6 Brol I 189 1935 ·24 THE CIEVILSTRY OF HEREDITY 105 Vorich, A and Szlend L Esperimens on spontaneous and chemically induced mucetions of bacteria growing in the cheapestat. Cold Sprag Harbor Sharp Qum Bio! 16 317 1951 106. Clarla J R. The mungenic action of nurous chemiab on licToccus aureus Proc OHabomu Acad Sc H4 117 1955 107 Treffen, H. P, Splocill, I und Belser NO A factor (or mutator gene) influencing mutation rates on Excheri chia coli. Proc Na Acad Sci +0 100+ 1954 106 Bruun, V Bacterul Genetics New Yorh, Saunders, 1953 109 Nech und Schull, I J Hinno Heredity Chicago Luiersity of Chicago Press, 1957 110 Reiner B. and Zamenhof S. Studies on the chemiany reactic groups of dearyribonuclck sads, J Biol Cbem 228 475 1957 01 Zamenhof S, Lerdy G Hahn E and Alerander HE Inactrition and onsabilization of the transforming prinaple by mutagenic agents. J Bact 72 I 1956 112 11cElroy 11 D Endence for the occurence of inter medates dunng mubation Science 115 6 3 195 113 Zamenhof S, Lady G Greer S. and Hahn, E Differ ential abilities of indiridiral heredity determinants in transforming principle / Bact 74 194 1957 114 Barratt, R. 1 and Team, E. L. Caranogenic muogas, ARH NI Ace Sd 1 1072 1958 115 Gellhorn, A and Hirschberg Im Edrors Invexogation of dirette stems for cancer chemotherapy screening Cancer Rer appl 3 1 1955 116 Zamenhof S Vathods and struments for the selective Tadipon of chromatin Rot Sci lustreets 171 1943 117 Zrlic RE and Bloom, 1 Imidation of of Ind- M Fidual cell. Science 117 48, 1951 ·pures and BIBIJOGRAPIY 95 118 Urez, R. B. Bloom, td Zirkle, R E.. Irredutoon of parts of individm cells. II Effects of an ultraviolet mu- Crobam focused on part of chromosomes. Science 120 197 1954 119 Kopec, 11 J Transphoonon of subcellular particles by micrury, Aon N Y Acad Sch 61 380 1937 120. Ephrud Taylor H Transformations allogenes do pneumocoque, Erpth Cell Res 2 589 1951 121 Hitchlogs, G H Elion, GB, Fakcy, E A Russell, P B. and 1 ander Werff H Studies on amlogs of pynoudines. Amals N Y And Sch, s 1318 1950 122. Zamenhof S. and Griboff G Incorporation of halogt nated pynmdines into the detyribonucloc code of Bacterim cou Noure 174306 1954 E col contulang S-bromural m deatyribonuclerc sad Nature 174 307 1954 123 Dunn, D B and South, JD Incorponbon of halogen ated promdding into the deoryribonucleic acids of Buc terum coli od ius bacteriophaga. Nature 171-305 1954 124 Zamenhof S. Reiner B DeGOYLONI, R und Rach h Introduction of unnatun pitundina into deatynbo nucleic acid of Eschericblu coll.Blol Cbem 219-165 1956. 125 Zamenhof S. DeGroninn, R. od Rich, K. Escberichia cole containing unnatural pynupidines in a dcorabo nuclac tad J Bact 71 60, 1956 126 Zamenhof S., DeGlovini, R. und Greet S Induced gene unablizabon Nature 111 827 1958 127 Laman, R. 11 and Pardes, A. B. Studios in mortigeneet Production of bacteriophage putant by a disturbance of deorynbomucleic word netbolam. Namre 178 529 1956 126 Benzer S and Frecke, E. Induction of specific mutations with S-bromournal Proc Nat Acad Sci H 112, 1958 129 Prusoff H Saudies on the mechanism of action of zathy Tunt. J Biol Chen, 226 901 1957 130 Smith, ) D and Martha R. EF The metabolism of B-zapanna Blocbem ] 66 323 1957 ·26 THE CLEN115TRY OP HEREDITY 131 Gordon, A1 P and Stachlen, VI Incorporation of 5-Auoroural into the auclac tad of tobacco mosuc vins. J Am. Chem Soc 30 23+0 1958 132 Dunes, W R. and Doherty J K Noclar and cytoplas mic organords in the living cell Ann V i Acod sa 51 1210, 1954 133 Goldgein, I. and Paul W Direct endence for midler sinthes of citoplagrac ribose nuclec acid. Proc Mat Acad Sci 41 874 1955 134 Bracket, J Brocbendcal Cytology Netr Jorma Aad Press, 1957 135 Hoagland \1 B. An enzymatic mechancen for amino Had activation in animal almues. Brocburn Biophys Acta 16 288, 1955 156. Hoogland, AI B. heller E B. and Zamecnik, PC En zymatic arbory activation of urdno acids. J Biol Cbem 218 345 1956 137 Zenxccruk, PC, Stephenson, V L and Heche, L. I In fermedate reactions in anuno tad incorporation Proc Vat Acad Sci H 7) 1958 13B Hoaglaond, VI B Zamecnul, P C and Stephenson, \I L. Intermedute reactions in proren biotynthesis. Blocblut Biopbys Acta 24 215 1957 139 Sonnenborn, T V The cytoplasın in heredity Heredt t+ 11 1950 1+0 Lwoff A Control and interrelations of metaboHc and virul discases of bactera. Horrey Lect 50-92, 1956 141 L Hentier P The CO, sensitivity problem in Drosophule. Cold Spring Horbor Syiap Quest Biol 1699 1951 142. Cospan, E Cytoplasmc inhentance Adr Genetics 21 1948. 143 \lichaelis, P Interactions between genes ind cytoplasm m Epilobrom Cold Spring Harbor Stup Qusar Biol 161? 1981 ·RIBLIOGELAPHY 97 14 llox T E and Stocking CR. The chloroplast. ATVC ture, Inderitance md enzymology Botte Red 13 14 1952 145 Ephrusa, B and Hortinguer H Cvroplasmc coptotucat of heredity Cold Spring Harbor Syrup Qunt Blol, 16 75 1951 176. Viitchell, VI B. and Mitchell, H h. As of "matemala Inheritance in \eurospors crisse. Proc Na Acad Sci., 31 412 1952 147 Jwes, AP The process of non-genic mutation in an unstable sum of yeast. Records Genetics Soc pret $ 379 1957 148 Cohen, G V od liopod, J Bacterul pendeuses. But Rot 21 169 1957 149 Deerc, CJ, Dulapey AD and Michelson, L D The lactase activity of Escherichia col-mutabile. Bact 57 355 1939 150 Wagner RP and Mitchell, H h Genetics rod leta Lolun. Men York, Wiley 1955 151 Hartman, PE Trusduction compartive ITCA in The Chended Beds of Heredity (Edited by W D llc Elroy und B Class) 406 Belomors, Johns Hopkins Press 1957 152 Adelberg E. A. The use of metabollal, blocked organ mms for the malysis of biosynthetic pathway Bact Raticus 1 253 1933 153 Zamenhof S Nuclerc acid anthros's brick-mutants of Escbribua col Abstracts Amy Chemical Soc 13rd Veeting !, 1958 15+ Coldschmidt, R. The tintend Basis of Erolnion New Haven, Inde, 1910 155 Petrunkeritch, A Alacroctolution nd the fosall record of Arschide. Anret Scientist 40 99 1952. 156 Cagle 1 The growth requiremenu md metabolic uc dirits of human ud animal cells in culture Proc 11th la Congres Brocber 1958 ·98 THE CHEVUSTRY OF HEREDM 151 Sato G Fisher H I and Puck, T T Alolecular growth reqwrenents of single mammalian colk Science 16 961 1957 158 Thomson, RI Paul J and Dandson, J N The mere bolk stabilim of the nucleic acids in culture of pure Arun of marmalan cell Biocbeth. ) 69 553 1958 159 Ovens, o Gey I h and Ger GO Growth of cells in agitated fund medium. Amals N Y Ace Sd 53 1039 195+ 160 Earl, W R Schilling E L., Bryant, J C and Evans I J The grouth of pare L grain mouc cells in flud Aspension cultures. Nst Cancer last 14 1159 1954 161 Puch, T T and Marcos, P I A napd method for viable cell otrigon and clone production with Hela cells in usmuc culture the use of r-imadated cells to apply condtioning factort. Proc Na Acad Sci, +1 432, 1955 162 Puch, TT llarc, PI Ind Cieciun, S. J Clonal grouth of mammalian cells in tieto I Exper lled 103 273 1956. 161 Puch, T T and Fisher H W Geneld of sometic mammalin cells ) Exper lled 104 427 1956 161 Puch, TT Cicctur, S. J and Fisher H. IV Clonal growth in tro of human cells aith fibroblask oxorptiolog | Exper Aled 106 145 1957 165 Bender A ray induced chromosome ibertadans mnomal dupknd human tout culture Sclerce 126 974 1937 166 Puch, TT. Action of radiation on LTTE lean cells Proc Nat Acn Sa H 772 1958 167 Dent, CE Forts ord to sympogum on unborn crrors of metabolism. Am J lled 22 671 1957 168 Vchoch, I A Vlecharons in genetic diseases of man. Ar la 2676, 1957 169 knot, 11 E. Sir Archibald Garro's Inbom Erms of Vetabolien" || Alleptonurk, Am J HMMA GRACTICS 10-95 195R ·BIBLIOGRAPHY 99 1/0 Harris, H and Robson, E. B. Cykmans. Am J lied 22 774 1937 171 hor, W E... Sir Archabald Garrods Inborn Erron of Actubollen L Cronuria. Am. J HIINA Genetics 10 3 1954. 172 Bern, AG Wilson s discax Am. ) lied., 22 747 1957 173 Waldenstrost, J The porphyn is inbom errors of metabolom. An.) Mied 22 758 1937 174 FNXI D Hypophosphatnsin. Am Med n 730, 1957 175 Gurrod, A E. Inborn Errors of Vetabolism London, Orford, 1923 176. La Du, B. Zannoni, Closter L to Secgmuller E.. The mature of the defect in tyrosine metabolism in Alaptonorm ] BiolChem, 230 251 1958. 177 Jervis, G A Phenylpyruvic oligophren. Arcb Neurol Psychiat 31 941 1947 176. hoor, W E and Hea DIY Pathogenetic problems in phenrlketonunt. Any lied 22 687 1957 179 Prunkrad, TAJ Inbom error of metabolism m red cells of congenital herpolytic mat. ATA. Aled 22 724 1957 180 Sanbury J B. nd VcGirr EU Spondc or ron endemic furul arconion with gorter Am I Tied 22 712, 1957 181 Holzel A horrower GAL and Schwurz V. Cilac tocci. Am J Med 22 703 1957 182 halter H Anderson, E P and Laelbachet hy Galactosem., I congenital defect in nucleotide tranferix. Blocbrm Blophys Act, 20 262 1956. 183 Puuhng L Itano, H A Singer S) and Wells, I C. Sickle cell rate, Molecular Doerte Science 110-543 1919 184 Ingram, \ \ Genre mutation in human haemoglobin. the chemical difference between portal und solle cell hacmoglobin Nature 11 326 1957 185 Ersten Out of my LITET yen Ne York, Philo sophical bran 1950 p 61

·No text on this page.

·INDEL Acrtabalır, 6 Coprok, bateral, 10, 12, H2 Add effect on DVA, 45 Cartu Lasadke oploy 19, Atranke, 63 Carcinogen Adrone, 27-29 33 77 31,51 3 4, 6,35 bodde, o Istrocarbom, 35 Adem triphosphate (ATP) Carte qents, 35 57 71 Adenylic iad, 90 Catalyx, 31 Abon, 77,7679 CeDdh Jan, 49 50 Akupracurta, Ser Alaprodure Chromosome, 19-21 35 45 Atrs, 4,24 56, 60, 63-65 67 Alha, effect on DV4.46 abportahan od 75 Adapton, Ser Horonpetek od ma plantation of 37 Alipton16 73,79 CAK, 65, 70 Aksla rent, 3 H Cochroust, st Alck, 67 Caricab 31 Amino kich, 14, 30, H4 60. TI B] Csentynet, 65 nal, 7 & 73 Courg directiod bi muhalla, 61 Amorty 7 Atrown of DA per col. 21 77 Color Wada 32 Aroptubum, 12. Colorimetde methods, 25 Aracrobac benidoru po grow Congeural detect, 75 Swe Glycolyo Comic 11 Analorien, 56-1, 61,71 Corilent band, 38 Antibod rhetence, r, , 34, 52 Crown-TET 45 57 Ascorbat, 51, Con 76 A DOCUK partice, 46 Cytocarunteboch 24 Cytochromes, 63 64 Bacte, 12, 19 24 25 35 19 41 H Cstogtes, St Cua Cytoplastic 49 50, 51, 52,7275 Cytopit, 1) 59-64 Rectopherc, Srl area, becremal Cytoplasm, Durda, 22.13 mherremot, 13 59-64 65 Seen Dachs on, Str fumon opłat Klock. rock,67 2,72,77-11 suk Bonc runt 13 pereche 61-44 45 -Brooroon, 31 Cytome, 713 37 Dipex, 66,69 Deot Tony lewd, Cincar, JL, 3611 Deonbonuckne, 24, 12, 47 cct, so Deorrbom, 26, .! chemotherapy of us Dsoryt back to beredary Yh Derynbak ders hooucka bredar ceply ode, 101 ·102 TUIE CHEVM) OF HEREDIT Deprotetiedon, 30 Diethyl mlfate, 53 Diferental confogution 25 3 +Dihydroryphen) Lalande (DOPA) 77 78 23-Dihydrotspberrylpyturked 77 10 6-Docthylantropurine, 29 Doncthyl rolfate, S) DVA, Vuclerc eod, deorytiba- Drosophils 9 19 20,9 10,2 ? Dock, 19 Gede, 45,9 13 19 13 34 +0,44 +5 4,52,54 56 58-60,63 6 71 70 chrokar Of TIE cytoplank, 61 rectan 77 79 Omotable, 49, 52, 54,5174 Genetke determinats, 3 Generos chamal blocbcmcl +8 microblar Gonorpe, 7 Glands, 60 secretion, 66 Glucone, 26,80 Glocou 1.phophate, 76, Glucanoe ord, Glycotton 6 Glytoly 7479 80 Groot, 76 Granure, 17 9 31,37 JA, ! Ex. 61 62 Electric charrell Electrophora, Enoltre, Enrot reactions Ser Ensto Eory TDCI, 6,7 12,17 12,24 40-42 47 60,61 66-77 78-81 depth e. 60 Epliou 52 Erythrocytes, 21 31 0,81 Erberibu cah, JJ 41 42, H 12,60 Esterfyny wents, 53 54 Erolerior, 46,5 7 74 acceleration of so Fecubal control, Feronettunon, 66, 79 Ferrou po, S) $ Flate, 22,13 Se als Carlos Fructoauton DAH Tree radicah, 53 54 Fructore 1 Odphopboxe, Truk-dy See Drwale Fangi 14 ) Hout omutagene tone 33 ccat on DVA +5 Ha a roten, 39 Hermoglobi 1 L Hotpoły the enemm. 76, RO Hemolytic reprocacch, Hopbull. 52,76 Home Abobor farm 12 ) + Heredury dret ad defect Tol s1 75-4,83 Here) 413 4.64 determinang, I 46-LIJ 32, 44 +66 mechuanom of 37 High-enery bood, 11, 12 Histo, 21 Ilonghuck 779 mudase, Ilornostne, 71 Hydrogen bond J7 II Galactus 81 Guctose-i-phosplure, 76, , 81 Galacto con 7400 Grocher doen, 76 ·103 INDEI 5 Hydroxymethylcytosise, pllydrotyphenylpytu 77 Hypercolesterolemis, 76 Inbora delart. 75 Lofoto maroc Mocy 76 Information aurrier 367 10,21 cb.call, 31 41 renetic, 19, 21 25 31, 34, 42, 43, 59 72 Inhibitor 72 In ccti, 33 Stres Dronephile Latermodary mechom, 4 59-64 65 Intermediate (petabolito) 70 Intwiec, a Loretera, 33 Lodotyden - 10 ID000- Ladotyrosine deshaloger, 10 Dumber of DNA molecula per cell, proportion purpa od pyrudna, 33 pooneous moto tan hetk palyonceood, e lanpowing, 53 Maternal inbertince, 61, 2 Jichants, 77 77 Vletabolle poche ry 70, 72, 73 75 77 Metabolt, 6, 72,73 Alcchionunc, 71 2 Viethylacerinc, 29 G-Vlahy Laminopurde, 29 S-Alethylcytone, 19 33 1-Alethylunion 29 2 Vietty Ironbre, 29 Alethyl lodide, 53 Alicrocophus 52 Alicroorgia , 51 75 77 13 See also viruses, bactene, footh lin, protagod ALCOROA, 25 60 Aliorupy 57 Virochoodie 25 Vodd of DVA, 11 tton-Crket, 38-40 Votards, 50, 5) JS Matusi eto, outgen, 47 4 953-51,75 cberrial, 51 53 st cytoplamuc, 61 Alutition 6,13 23 25 45 +1-51,6 64, 65, 67 69 70-73 TT 11 back? cemur of topiron 61 Jurected, 56-58 happe partecke, 62 Lectum, 66,70 LHC, delom of X, . Lher 21, 25 33, 31 Van (com) 50, 52 Lunah 21, J3 41 42 Snelse Von moont of DVA per cell, 22 cell 3 cel no coltare 75 coord of betty 54,13 tactic blod, 7273-0 heredis Heth 75-0 hart 1,19 nett peces M, 77 mitorced, SO SI SU SE 56 Ite ruhi. 61 ·THE CHEVILSTRY OF ILEREDITY 104 teaty as ktbal los 72 me 73 no 12 נל ciaות nite, 51 52,74 rcct, 73 pantolon, 10-53 Vlycobacterium tuberculose, 33 Neurompon, 63 6470 poly 67 Vetrostnoon bakes 26-} H4 H 59 42 Mon-particule fructen 25 Nucky cht, 26-47 dentrommon of 45 deor, robo (DVA) 1 19 19 21 76, 21-39 41-47 9 59 62 0 functionally Daks, 45 46 Tobal, 24 20 molecular recht of 24,33 40, 46 Totate, o oltre 45 OCCUITECT o 24 mbo (RNA) 16-19 21, 2) 27 29 HJS 41-41, 56 55-60 Anthem of titrato at 12 poputy of +7 Nocleolus, 57 Tockoprorch 14, 19 20 21 , +5 ocleuch, 30 Sockcoude dipbogie, 40 \ochoduk, 26-31 37 R4), 43 +9, 60, Sucks, 4 25 57 59 60, 661-65 Pnberaw-andst torderac, 81 Puxraxt raice, 47 Pingecrom, 62 Purabic pcca, 71 Pentaur 76 Pepodes, Peripheral reactions, S 7 59 55 + Perability of the cell membrane 6,70 Phars, Sulful bacterial Phenotyp, 7 Phenylsinn, 77 79 Pricay Deroport, 76, 77, 70 Phenylpyrunud, 71, 70 Pbocphare. Ser Pboxpbone sa Phoppboedolpytuture, Poomphorroctolmu, 80 2 Phosphortycente RO Phosphork az 26-70 16 14, 19, 467 53 54 Plant, bugter 24 JJ Q2 hybrida schon in 63 Pluspore, It Planne, Sor Gede, cytoplam Plache, 2 PromoCort10 12, Pollen, Poly-dorth cd, 41 Pulso to Poly rockorcke phosphoryter 40 Polyuccheride, 17 Porphyrn, 70 Posjon edet, 10 Portor Primer 41 - + p-Propholstooc, SI Proportions of Purtand Pyrendoncs, 3) Procerum, 21 Procen, 14 21 23 29 1981 synthesk 4,59 60 Procoples, 15 Ochronoer, 77 Operenc-one-cym his poche 73 Oporom, 51 ·IYDET 105 Protozo, 24 Sureptococcus pneumonbec, Partoe, 29-10 KSH Sce Porumococcus Pytadios, 29-39 54 Somer 26-0, K3 Pyrophosphatt, 40 Store Deotynbore, Gilector, Glocore, Ribas Radon, 45 , 50, 51 53-55 SR Synthesis of polynucleotides 70 75 enrymt, 40 41 focus of $6 non-enzymerk, 43 ng by 45 uuttokt, 23 51,56 Teta, 13 Terrockcocid, 11 S 18 Xter 33 Thermoclinton, 51 Radioactime demit, 51 Thtcoin 71 Thymune, 27, 29 33 37 ILS Red Wood cells, Ste Erythrocytes Thyme, 21, 33 Replication 4 38-41, 40 Thyroglotatin, 80 Repellat, 22,33 31 Thrond boru 004, 140 Requirement ThyTorbe, to bwolutt, 8 Two colur, 16,73 pustil, Trimeductoa, 14,67 Ractre Topdaccorto, mokruh of acaricd. SK Transforming phenomenon Hunt of bactenul Tu cyce, Trasannons Retinoblatora, 52 Katry 4, 47 53-56 Ribodoclenue, 11,25 60 phenomenon, 10-14 43 49 Rbor, 6.27 19 poondoke, 111) 42, 47 54-57 Riboeck, HD Tryptophane, 12, 67 Riboude, 10 TWRL 31 Rickett, 25 37 63 Tyroketonurg, 74, 75, 79 RNA Sre Nocleh dnbo Tyronxe, 77 T robot, 77 79 Satinry rand, 19 20 Seption, Vladdon, 63 nan Selado, burl, 6, 74 Unded-phosphato poco Sell-oven tot 53 54 (UDPG) Suct cell beton, $1 L rook mat, 12 Stcke cham, 19 Spretheny themel 31 abne, Spermoteo, 19 21, 22, 31, 1960 Im L, I, 14-19 24 33 19 33 Spberocytes 35 44 43 49 52, 54,41 Ser Hemolyot sama olonel 17 11,3) Splech 31 becita (bacteriophar Sponde creion for htt) 1+ 1+ 2+ 3 H 45 76,00 5256

·106
DIE CHERIISTRY OF MEDITY
lapin Ste Ascorbiceod
fam., 6., 73
mynallix, is 16
Acephalith, 18
aceptualomyeli, 18
hybrld, 17
mfectre matril of 15 18
nfocah, 24
populome, 27
plant, 15
polomyelith, 18, 24
Anthede, 18
tobacto Donk, 18, 24, 35
Het authors, so
1 dan 77 73
4 m de76
\*s) diffraction, 48,39
Teht, 33 63 64
prunt, 63 64