~2]OOK ['~EVIEWS

Principles of Population Genetics (2nd edn)

by Daniel L. ftartl and Andrew G. Clark, Sinauer Associates, 1989. £23.95 (xiii + 682

pages} ISBN 0 87893 302 6

A major appeal of population genetics is the reductionist hope that the biosphere 's diversity can be understood as extensions of the minutiae of natural selection, mutation and genetic drift. In real life, practitioners enjoy tantalizing glimpses of the possible, provided by the mathematics that flow from rules of genetic segregation, but mire in the practicalities of statisti- cal inference from real data. Students new to population genet- ics often wilt at the contrast with other biology courses. The shift from qualitative descriptions and models to quantitative (i.e. math- ematical) ones, in conjunction with a shift from so called 'hard' infer- ence to statistical inference, is diffi- cult. Hartl and Clark's text does not ease this transition. This is most apparent in the first chapter with the gulping title of 'Darwinian Evolution in Mendelian Populations'. The chapter is about types and measures of genetic variation and is essentially not about the questions of population genetics and why they are asked. The summary of issues and history that begins the chapter takes up about as much space as the discus- sion of inferring restriction site variation that soon follows it.

What Hard and Clark have provided is clearly written, quite current and impressively thorough. In addition to traditional mendelian population genetics, the text includes quantitative genetics, some ecological genetics and a brief touch on the genetics of speciation. The large chapter on molecular population genetics is excellent. Much of the book con- sists of empirical results taken from the primary literature, and the authors have taken pains to inter- sperse this with the mathematics.

The writing is precise and moder- ately terse. Perhaps the best measure of the authors' care and competence is the high level of consistency with which the text informs over a wide range of top- ics, both theoretical and empirical.

One thing the authors might have done to promote accessibility - to help more students 'get it' - - would have been to describe major issues in their historical context. The history of population genetics, replete with great insights, interest- ing characters and rancorous debate, can be very engaging. Population genetics, in practice, has a central conundrum: theory, braced by nifty math and inaccu- rate assumptions, cannot quite handle the intricacies of nature. It is not difficult to show that this conflict pervades the field to this day, as it has since before the mod- ern synthesis. Any student, provid- ed with an honest appraisal of the field (which this book certainly is) and lacking the perspective of his- tory (i.e. consistent progress in the face of this consistent difficulty), can easily become discouraged.

Fo .tudent s6 tlcate Evolutionary Genetics

by John Maynard Smith, Oxford University, Press, 1989. £16.95 (v + 325 pages} ISBN 0 19

854215 1

This book is written as an introduc- tion to the parts of population genetics that are of importance to evolutionary biologists. The clear and graceful writing makes it a pleasure to read and the wide range of topics discussed will be sure to touch on the interests of almost every evolutionary biologist. This book introduces the reader to much of elementary population genetics and to most of the current controversies in evolutionary biolo- gy. Although Maynard Smith has played a central role in many of these controversies, he largely succeeds in making clear the differ- ence between widely accepted

TIG OCTOBER 1989 VOL. 5, NO. 10

Perhaps as a result of concerns over length and thoroughness, very little history is included in this text. The book conveys the feeling of a reference, like an encyclopedia: the writing is concise; the coverage is broad; and it is structured with each chapter divided into a great many smaller, nearly independent sections.

For students with some prior knowledge of the issues and the difficulty of population genetics, or for instructors willing to create this context, this is clearly the book of choice. For clarity and complete- ness it is unsurpassed. However, to the uninitiated it may seem more like the 'Details' rather than the 'Principles' of population genetics. A straightforward reading is not likely to promote an understanding of the motivation for the questions of population genetics nor, ultimately, an intuition for evolutionary forces.

JODY HEY

Museum of Comparath~ Zoologo,, Harvard University, Cambridge, MA 02138, USA.

facts and his own opinions. His involvement gives a personal tone to the book that makes it engaging in a way that detached objectivity could not.

The book can be divided into three overlapping parts. The first contains the basics of population genetics, mutation, selection, drift and recombination. The presen- tation is lucid but brief. The focus is on deterministic processes. Genetic drift and inbreeding are presented in only enough detail to introduce discussions of kin and group selection. No diffusion equations are to be seen, but a few results from diffusion theory are presented without derivation.

The second part of the book contains material that has been the focus of much of Maynard Smith's recent research: game theory, kin selection, group selection and the evolution of sex and recombina- tion. Maynard Smith is especially good at making these complex topics clear, although he succeeds in part by ignoring many of the genetic details presented in the

~ ] O O K H l l E V I E W S

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 dis- cusses a host of fascinating evolu- tionary problems that arise from some recent discoveries in molecu- lar biology. This material is not so much a description of established knowledge as it is a preview of coming attractions for populat ion geneticists who have learned the basics and are wonder ing if all the interesting problems were solved by Haldane, Wright and Fisher.

Most of the 14 chapters contain several problems and some sugges- tions for computer exercises. The problems are usually straightfor- ward and worthwhile. The comput- er exercises are, to say the least, ambitious. Many of them would 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 fash- ionable, it conveys an odd message 1o the reader. On the one hand, the details of the theory" seem somehow 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 know- ing what assumptions these results are based on.

As a text, this would be a diffi- cult book 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 book would know what the subject is about and should be convinced that the ideas are important but is unlikely to be able to evaluate crit- ically more advanced literature or solve problems not directly treated in the book. This disadvantage is

Ph. 0 ' a.nd the hint scmnce

The Foundations of Human Genetics

by Krishna R Dr0namraju, Charles C. Thomas, 1989. $40.75 (xiii + 211 pages) ISBN 0 398

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 scien- tific research occurs, and seems likely to prove rewarding, then those who 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 who also gravitate to the new field. He develops these ideas further by referring to Kuhn, who has argued that 'extraordinary' (or revolutionary) science, which is the major force behind scientific advancement, eventually gives way

Erratum

Genetic mosaics and cell l ineage analysis in plants, by Scott Poetbig

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

Figure 3 in this article was printed incorrectly, as a neg- ative rather than a positive image. The correct figure and its caption are repro- duced 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 be tween molecular genetics and evolutionary biology.

MONTGOMERY SIAIXIN

D@artment cf 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 development 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 book The Act of Creation that truly original discoveries are extremely uncommon and in fact no more than a handful of examples can be found in the entire history of science. In almost all cases an apparent ly new 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 knowledge 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 clas- sir}" paradigms into no less than 24 different types. For example, a 'true' paradigm is represented by Mendel's laws of inheritance, as opposed to a Talse' paradigm such as Lysenko's theories. Or again, an