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Nuclear Power Another Way, by Finding Evidence for Dr Sapp Attributes This to the Different I.R.S _N_A_TU_R_E__ vo_L_._3_31_J_s_FE_B_R_u_A_R_Y_1_9s_s __________________ 800KREVIEVVS---------------------------------------s7_3 undermine the chromosomal monopoly in heredity received scant consideration. Nuclear power another way, by finding evidence for Dr Sapp attributes this to the different I.R.S. Fincham genetic determinants in the cytoplasm. styles of science administration in the two Dr Jan Sapp's history of these doubts countries; the American 'free market' and disputes makes interesting and pro­ pulled research into the most readily Beyond the Gene: Cytoplasmic Inheritance vocative reading. The interest comes exploitable areas, whereas in the more and the Struggle for Authority in Genetics. largely from extensive and well-selected professorially directed German system By Jan Sapp. Oxford University Press: quotations from the publications and (in founder effects were of more importance. 1987. Pp.266. $35, £32.50. some cases) the personal correspondence According to Dr Sapp, the American of some of the main protagonists. The verdict on the German work was "not GENETICISTS have always tended to believe provocation, at least for this reviewer, proven". But his quotations from Ameri­ that organisms are determined by genes comes from the author's determination to can textbooks of the period show a gen­ located on chromosomes in the cell explain the development of genetics in eral, if tentative, acceptance of a role nucleus. Until the advent of gene cloning, terms of struggles for authority and power for plastids in heredity, an acceptance this belief depended entirely on the between a Mendelian orthodoxy and encouraged, as he points out, by the fact Mendelian behaviour of nearly all varia­ cytoplasmic heresy. that they were visible structures with tion that could be inherited through sexual The three central chapters are mainly apparent continuity through cell division. crosses. Sceptics were able to argue that concerned, respectively, with the strong The work started by Ephrussi led to the Mendelian variation might be only inter-war school of German extranuclear extension of genetic status from plastids to scratching the surface of an essentially geneticists, the work of Tracy Sonneborn mitochondria. Although he had close invariant species-specific substructure. at the University of Indiana, and the post­ links with the American Drosophila This was the view of some evolutionists, war development of yeast (Saccharomyces geneticists, especially A. H. Sturtevant who thought that differences between cerevisiae) mitochondrial genetics in Paris and G.W. Beadle, Ephrussi was always species and higher-order taxa were based under the leadership of Boris Ephrussi. sceptical about monopoly control by on something more fundamental than the In Germany, Carl Correns and his suc­ chromosomal genes -- a legacy, the chromosomes. Embryologists also tended cessors, notably von Wettstein, Renner author thinks, of his background to doubt the overriding importance of the and Michaelis, found many examples of in embryology. His study of 'petite' chromosomes, whose apparent constancy maternal inheritance in green plants, (respiration-defective) mutants in yeast, made them seem quite unhelpful in mostly involving chloroplast function. later extended triumphantly to the DNA accounting for development. Thus, during This led them to postulate a genetic role level by Piotr Slonimski in Gif, was largely the great expansion of chromosomal for the plastids and to the concept of a responsible for extranuclear inheritance genetics during the 1920s and 1930s, there 'plastome' acting in parallel with the being welcomed into the mainstream of was always some scepticism about gen­ genome. This was not an unorthodox genetics. The early recognition of respira­ etics on the part of other biologists. At the view in Germany, in striking contrast to tion deficiency as based in the mito­ same time, some geneticists began to the United States where extranuclear chondria, followed by the firm identifica­ tion of mitochondrial DNA, made it possible for Slonimski, and a number of other workers in strong laboratories in the United States and Australia, to explain many kinds of respiration defect as due to deletions or other mutations in specific mitochondrial genes. At nearly the same time, DNA was also identified in chloro­ plasts and a similar detailed analysis of chloroplast genes was soon under way. So far as this part of his subject is concerned, Dr Sapp's book might have been better entitled The Gene Rides Again-- Outside the Nucleus. Sonneborn's experimental organism, the ciliate Paramecium aurelia, proved a rich source of examples of non-Mendelian inheritance. One of these, the killer phenotype, turned out to be due to endo­ symbiotic bacteria which had, of course, their own DNA. Other examples were not easily accommodated within the DNA paradigm. One of these concerned the specific surface patterning of the cell. Sonneborn showed that an alteration of the pattern by microsurgery could be transmitted through an indefinite number of subsequent cell divisions. an example of new structure guided by pre-existing structure, a mode of inheritance perhaps Back-breaking- children known as 'breaker boys' earned a dollar a week clearing the flow of pieces of coal through the chutes in an anthracite mine of the 1890s. The picture is taken from restricted to cells that never have to American Environmental History, 2nd cdn, by Joseph M. Petulla, an illustrated social and undergo cycles of dedifferentiation and economic history of the United States in the light of the nation's changing environment and of redifferentiation. conservation issues. Publisher is Merrill, Columbus, Ohio, price is $24.95. Equally novel were the results of L-------------------------------------------------------------------~ experiments carried out in collaboration © 1988 Nature Publishing Group _s7_4-------------------------------------BOOKREVI8NS-----------------N_A_T_u_R_E_v_o_L_3_3l_l_s_FE_B_R_u_A_R_Y_l9__88 with G.H. Beale on the inheritance of continues, though the principles at issue alternative antigenic specificities. The are not made altogether clear. 1 TheANS l class of antigen to be expressed from Throughout the book there is a steady 10urna1s among a number of alternatives was tendency to under-rate the open-minded­ determined by the cytoplasm, with the ness of geneticists. To take one example, Your number one possibility of temperature-induced switch­ in 1949 G . W. Beadle wrote a semi­ source for current ing from one class to another. But the popular article, "Genes and Biological information about fine specificity within each class was Enigmas", which included a careful NUCLEAR determined by alleles of a nuclear gene. review of Sonneborn's main results. He Sonneborn postulated the existence of concluded that there could be "no doubt ENERGY 'plasmagenes', replicating in the cyto­ whatsoever" about the existence in plasm but drawing some information from Paramecium and other organisms of cyto­ NUCLEAR NEWS the nucleus. An alternative interpretation plasmic units "capable of a limited degree NUCLEAR SCIENCE was advanced by Max Delbruck, who sug­ of autonomy"; but he went on to doubt & ENGINEERING gested that cytoplasmic propagation of whether they were responsible for alternative patterns of antigen synthesis "primary control of protein specificity". NUCLEAR might be explained in terms of steady There are some interesting points to TECHNOLOGY states, with gene products acting so as be made here; the lack of knowledge of TRANSACTIONS to stabilize the conditions for their own protein structure and synthesis at the time synthesis. This interpretation, interest­ Beadle wrote, and the tricky nature of the REMOTE SYSTEMS ingly enough, was considered as quite term 'autonomy'. But Dr Sapp seems to TECHNOLOGY reasonable by Ephrussi in his book regard Beadle's article merely as a PROCEEDINGS Nucleocytoplasmic Relationships in polemic; in his summarizing chapter he FUSION Micro-organisms , published in 1952. It refers back to it as a "public attack" on TECHNOLOGY still seems reasonable today, but the Sonneborn's work. For free catalog phenomenon has still not been adequately Other examples cited in support of the contact: investigated at the molecular level. book's thesis verge on triviality. Thus the Sonneborn's discoveries remain highly journal Genetics once rejected a paper, 555 N. Kensington Avenue interesting, but more as models for cellu­ nothing to do with cytoplasmic inheri­ La Grange Park, Illinois 60525 USA lar differentiation than as challenges to tance, apparently on the grounds that it 312-352-6611 Telex: 4972673 gene determination. was not based on adequately defined Chapter 6, headed "The Cold War in crosses. This becomes a "mechanism of Reader Service No.22 Genetics", recounts, among other things, control to maintain orthodoxy". Some the leading part that Sonneborn took correspondence between Ephrussi and in trying to mobilize opinion against Norman Horowitz, which most would Lysenkoism in the Soviet Union; he regard as an exchange of banter between happened to be President of the Genetics friends, is elevated to the status of "social THE Society of America at the time. In spite of negotiations" about adjustments in the occasionally expressed misconception authority. In his final chapter Dr Sapp MANAGEMENT that cytoplasmic heredity was Lysenkoist, resorts increasingly to arcane sociological Lysenkoism had nothing to do with the jargon to describe interactions between OF AIDS location
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