The foundations of human genetics

The foundations of human genetics

~]OOK early chapters. Still, a close reading will indicate that the necessary qualifications are present. The third part concentrates on molecular ev...

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early chapters. Still, a close reading will indicate that the necessary qualifications are present. The third part concentrates on molecular evolution and evolution of the genome. Maynard Smith discusses a host of fascinating evolutionary problems that arise from some recent discoveries in molecular biology. This material is not so much a description of established k n o w l e d g e as it is a preview of coming attractions for population geneticists w h o have learned the basics and are wondering if all the interesting problems were solved by Haldane, Wright and Fisher. Most of the 14 chapters contain several problems and some suggestions for computer exercises. The problems are usually straightforward and worthwhile. The computer exercises are, to say the least, ambitious. Many of them w o u l d be serviceable Masters' and Doctoral theses. Maynard Smith's approach to the subject is definitely theoretical but empirical studies are introduced whenever possible. Some of the harder theory, still not very hard by the current standards of the field, is put in boxes separate from the text. Although this style is currently fashionable, it conveys an odd message 1o the reader. On the one hand, the details of the theory" seem s o m e h o w less important and can be ignored. Yet the text makes it clear that it is impossible to understand how to interpret theoretical results and relate them to data without knowing what assumptions these results are based on. As a text, this would be a difficult b o o k to use for all but the most sophisticated students. The


succinct presentation makes it easy to read but hard to extract details from. A student using only this b o o k would k n o w what the subject is about and should be convinced that the ideas are important but is unlikely to be able to evaluate critically more advanced literature or solve problems not directly treated in the book. This disadvantage is

Ph. 0 ' a.ndthe hint scmnce The Foundations of Human Genetics by KrishnaR Dr0namraju,CharlesC. Thomas, 1989. $40.75 (xiii + 211 pages) ISBN0 398 0~37 8 'And what were you doing before all this DNA stufff' asks one human geneticist of another. It's not the answer that is of interest but the question itself. The author of this history of human genetics argues that when a new direction in scientific research occurs, and seems likely to prove rewarding, then those w h o transfer their energies to it are those who are likely to be the more successful in their careers, to be rewarded with grant support, and to be more accepted by their colleagues w h o also gravitate to the new field. He develops these ideas further by referring to Kuhn, w h o has argued that 'extraordinary' (or revolutionary) science, which is the major force behind scientific advancement, eventually gives way

Erratum Genetic mosaics and cell lineage analysis in plants,

by Scott Poetbig 77(; "3, 273-277 (August 1989)

Figure 3 in this article was printed incorrectly, as a negative rather than a positive image. The correct figure and its caption are reproduced here. A periclinal chimeml tobacco plant carrying an albino mutatkm in the L2 layer of the meristem. The green tissue in this chimera is derived from the L3. The L1 lineage is restricted to the epidermis. Although the L1 is genetically green, the epidermis in this chimera is colorless because chloroplasts do not differentiate in most epidermal cells. TI~; O(:T~mI'~ 1989 \'()L. ~, XO. 10

offset by the advantage of having the subject presented as an exciting and controversial field that is the bridge b e t w e e n molecular genetics and evolutionary biology.


[email protected] Zoologv, b'niversit),of Cal{fi~rnia,Berkeley,CA 94720. USA.

to 'normal' or routine science which is often repetitive and dull. And this situation then continues until another 'extraordinary' new d e v e l o p m e n t occurs when the same process starts all over again with the enlistment of converts to the new science. Many will no doubt sense there is a ring of truth in this. However some may be more inclined to agree with Arthur Koestler in his b o o k The Act of Creation that truly original discoveries are extremely u n c o m m o n and in fact no more than a handful of examples can be found in the entire history of science. In almost all cases an apparently n e w discovery or inn()vation is based on preceding work. Dronamraju uses Kuhn's ideas in tracing developments that have occurred since the early part of the century in the main areas of human genetics: natural selection and mutation, biochemical genetics, medical genetics, cytogenetics and finally human gene mapping. As might be predicted, because of the author's early association with Haldane, the section on natural selection is the most rewarding. However, almost a third of the text is devoted to Kuhn's views and the idea of paradigms, yet the term is never clearly and specifically defined. At one point 'A paradigm is what the members of a scientific community share...' which implies a body of k n o w l e d g e and ideas. Yet at another point 'The members of a paradigm have shared goals...' which implies that it refers to a section of the scientific community itself. The author proceeds to classir}" paradigms into no less than 24 different types. For example, a 'true' paradigm is represented by Mendel's laws of inheritance, as o p p o s e d to a Talse' paradigm such as Lysenko's theories. Or again, an


'incipient' paradigm is exemplified by cytogenetic studies between 1921 and 1956, and a 'transient' paradigm by Painter's report of the human diploid chromosome number as 47. But does such categorization really add anything significant to our understanding? It does lead the author into some trivial considerations, such as the '...competing paradigms, namely the PhD and MD members of the American Society of Human Genetics', and to be disconcertingly repetitive. Furthermore, such an approach leads to the development of human genetics being viewed at a distance. But the most intriguing problems lie in the details. Dronamraju seems aware of this, for he asks, for example, why blood group genetics, despite its immense clinical importance, never attained the same standing as the mathematical theory of natural selection as developed by Fisher, Haldane and Wright, but he fails to present a critical in-depth analysis of this matter. Yet it is in the pursuit of such detail that the historian of science can have something really important to say. Moreover, the most revealing historical studies in science are those that examine events in the social and political context of the time. The author, for example, relates the cataclysmic effects of the atomic bombings in 1945 to the subsequent award of the Nobel Prize the following year to H.J. Muller for his work on mutagenesis and his then becoming the first president of the newly established American Society of Human Genetics, a society which thereafter had such an enormous impact on the development of the subject, both in the USA and elsewhere. Unfortunately Dronamraju only occasionally presents such an historical analysis. Often he is content to catalogue events merely in some sort of chronological order. The writing of a satisfactory history involves a great deal more than this.

ALANEMERY l:niversiti' of Minburgb Medical School, Teviot Place. Edinburgh EH8 9AG. ~'.


PlanPrace ~i ',~:~ ~i:

Plant Molecular Biology, A Practical Approacl:i" edited by C.H. Shaw, IRLPress. 1988. £29.00/U5558.00 hbk. £19.00'USS38.00pbk (vx + 313 pages) ISBN1 85221 05' 5 Few disciplines have evolved as rapidly as molecular biology. Any editor attempting to compile a collection of useful molecular techniques faces a daunting task. Delays in publication virtually ensure that many of the protocols in a manual are out of date before it is in circulation. Important breakthroughs allow us to ask questions that we had not even considered a year before. Further, techniques are a very personal matter. Most of us hold very strong opinions about the 'correct' way things should be done. In this context, compiling a successful techniques manual would seem to be a virtual impossibility. Nonetheless, brave souls endlessly continue to turn out manuals. P l a n t M o l e c u l a r BioloRv, A P r a c t i c a l A p p r o a c h is a compilation

of 11 chapters contributed by individuals active in the field. The book covers areas of plant nuclear and organellar molecular biology as well as C h l a m l , d o m o n a s and cyanobacteria. The stated intention is 'to provide the newcomer and the practitioner with clear and sensible protocols to enable them to perform meaningful experiments in plant molecular biology'. Does it succeed in the stated purpose? Partially, with a heavy emphasis on 'newcomer'. As in any compilation, the quality of the contributions varies widely. Several of the chapters are very well written, thorough and informative. Others are already hopelessly out of date. Of course, many of the techniques described in this book have not changed significantly. DNA and RNA are still the same molecules that they were several years ago. A single source of reliable protocols for nucleic acid isolation, characterization and manipulation will certainly help those new to the field immensely. The chapters covering "N(; OCTOBt".R 198,9 VOL.5, \o. 10


these subjects are well written and thorough. Similarly, protocols for organelle isolation should prove useful to the novice. The development of simple and reproducible protocols to generate transgenic plants is probably the most important recent breakthrough in plant molecular biology. There are reports of successful transformation of new species literally every, month. In this context, the chapters on transformation are dated. The technology described in the chapter on A g r o b a c t e r i u m was the state of the art in 1985. The chapter appears to have been written several years before the book's publication, with only a minimal effort to update it, as evidenced by the list of references. The companion chapter on direct DNA transfer, although not as old, does not cover one of the most exciting advances in the recent history" of the field, namely the particle gun. There are other notable absences from the manual. For example, there is no discussion of the use of the [3-glucuronidase (GUS) histochemical assay as an alternative to tissue-specific localization. This extremely useful tool was widely available in 1987. Considering the large number of labs currently using GUS analysis, standard protocols and 'watchouts' would certainly be in order. This book should be viewed as a base for practicing molecular biology in a variety of photosynthetic organisms. The protocols provided should be taken as starting points for further refinement. There will almost always be alternative and in many cases far simpler available protocols. With the possible exception of the plant transformation material, the deficiencies of this book are mostly attributable to the rapid pace of advancement of this exciting field, not to any lack of diligence by the contributors. Nonetheless, when viewed as a whole, the book should prove to be useful for those new to plant molecular biology. If you don't know where to start, this is a good place to begin the journey.

HARRYJ. KLEE Plan t Molec ilia r Biolqw Gro t¢p, ,llo n san to Co., St Louis. MO 6y98, USA.