Genes, Peoples and Languages.

Luigi L. Cavalli-Sforza. Penguin Books, London. 2000. Pp. 228. Price £18.99, hardback. ISBN 0 713 99486 X.

Anthropological genetics is a fascinating field that provides us with a reflection of our past; a view of our species’ history based on patterns of genetic diversity among and within living human populations. Genetic data can be used to detect signatures of past history that might otherwise be unavailable, dealing with events before written or oral history. The study of the genetic history of humans is also often difficult to understand from a literature necessarily laden with complexities of molecular biology, population genetics theory, and statistical methods. Teaching this subject is often complicated by a lack of material clear enough to present to the non-specialist. Fortunately, Genes, Peoples and Languages helps fill this void. This book provides a non-technical summary of relevant work on human genetic diversity and history, much of which has been dealt with in the comprehensive publication History and Geography of Human Genes, written by Cavalli-Sforza, Menozzi, and Piazza (1994, Princeton University Press).

The book is organized into six chapters. The first nicely introduces the use of genetic data for analyzing population history, covering a variety of topics in a clear and non-mathematical presentation, including ‘race’, molecular biology, genetic distance, and isolation by distance. The second chapter reviews the evolutionary forces and gives one of the clearest discussions I’ve seen on building evolutionary trees (even though I would argue that trees are not always the most appropriate way to illustrate genetic distances between populations within a species). Chapter three discusses the ways in which genetic data have been used to help reconstruct the origin of modern humans, including discussion of ‘African Eve’, Y-chromosome polymorphisms, and microsatellite DNA. Discussion of these technical issues is done clearly and concisely, although I disagree that the data provide strong support for a recent African origin of Homo sapiens. I would argue that the data are also compatible with a much older history of the lineage leading to modern humans that includes genetic contributions from ‘archaic’ humans outside of Africa. Chapter four focuses on the genetic evidence for late Pleistocene and Holocene population expansions, with primary attention given to the work of the author and colleagues on the demic diffusion of agriculture from the Middle East into Europe. Chapter five reviews the author’s work on correlations between genetic and linguistic ‘trees’, arguing for correlated dispersions of genes and culture. The link between language and genetics is expected as a result of gene flow, although I wonder how much of this correlation might reflect isolation by distance rather than large-scale dispersions and migrations. As with the modern human origins debate, alternative models often can be applied to the same patterns of variation. Chapter six describes briefly some of the author’s ideas regarding cultural transmission and evolution with particular attention to linguistics, providing a link with earlier chapters.

Although I disagree with some of Cavalli-Sforza’s interpretations of the modern human origins debate, I thoroughly enjoyed this book. It was clear and informative, written by a pioneer in anthropological genetics. The easy-to-understand treatment of genetics and population genetics, combined with a reasonable price, make this book worthy of consideration in a variety of anthropology and biology courses.