Books and Arts

Nature 451, 771-772 (14 February 2008) | doi:10.1038/451771b; Published online 13 February 2008

Genomes evolve, but how?

Axel Meyer1

BOOK REVIEWEDThe Origins of Genome Architecture

by Michael Lynch

Sinauer: 2007. 510 pp. $59.95 (hbk)

"Nothing in biology makes sense, except in the light of evolution," said the great geneticist and evolutionary biologist Theodosius Dobzhansky. Twenty-five years on, genomics as a discipline has yet to embrace evolution fully. Michael Lynch is an exception. His timely textbook demands that population thinking, population genetics and evolutionary theory be meshed more explicitly. After all, genomes did not appear suddenly from nowhere, and mutational changes from single base-pair substitutions to whole-genome duplications are at least one basis of molecular as well as phenotypic evolutionary change.

As the cost of genome-sequencing falls and more genomes of the major model systems are sequenced, evolutionary biologists have more say in which organisms will be investigated next. Population samples of, for example, the model species Drosophila (fruitflies) are a good target.

Yet this line of research is still driven strongly by technical innovation, such as the speed and cost of data collection, rather than the testing of theories that might direct future experiments. Genomics research is progressing incredibly fast, off the back of genomic data that are being produced ever more rapidly. Still in a stage of wondrous discovery, this nascent field today evokes the excitement of the early days of natural history.

Lynch is a population geneticist who has made major contributions to numerous evolutionary questions and recently expanded his interests to genomics. He has published landmark studies on mutation rates, gene duplication and the functional diversification of genes.

In The Origins of Genome Architecture, he advocates using population genetics to understand genomes because the mechanisms involved can explain changes in gene frequency across generations and elucidate genome evolution. For Lynch, population genetics and some non-adaptive mechanisms in particular suffice to understand genomic evolution. He argues that invoking 'mythical macroevolutionary forces' is unnecessary.

Almost every page introduces interesting, unanswered problems — a goldmine for students in search of a thesis topic.

Lynch goes a step further by combining molecular mechanisms and evolutionary theory into a coherent evolutionary genomics framework and claiming it as the next phase of evolutionary biology. The ability to straddle both disciplines is rare and hardly attempted in the other direction — few molecular biologists know much about evolutionary biology. Rightly, Lynch laments this asymmetry.

This book is a must-read for every genome researcher; evolutionary biologists will also profit. It reviews and analyses, competently and thoroughly, a huge range of topics, from the origin of eukaryotes to sex chromosomes. It is the best, most up-to-date and thorough summary of genome evolution published. Arguments, hypotheses and supporting data are presented clearly and cross-referenced.Only the most necessary equations interrupt the flow. Almost every page introduces interesting, unanswered problems, making it a goldmine for graduate students in search of a thesis topic. Rarely have I scribbled so many pencil marks in a book's margins.

The last chapter, distinctively entitled "Genomfart" (meaning 'place of passage' or 'the way forward' in Swedish), discusses how much scientific meat lies behind fashionable buzzwords such as complexity, modularity, robustness and evolvability. It alone provides enough intellectual fodder for a stimulating seminar series. Not every evolutionary biologist, genome researcher or 'evo-devo-ist' will agree with Lynch's strong opinions that largely non-adaptive forces shaped genomes, but it is a debate worth having.

As long as we remain unsure what a gene is, we are a long way from understanding genome evolution. That so much is still unknown should not worry us. Rather, it should reassure the next generation of evolutionary genomic biologists that there is much to be discovered.

  1. Axel Meyer is professor of zoology and evolutionary biology in the Department of Biology, University of Konstanz, 78457 Konstanz, Germany. He is co-editor with Yves Van de Peer of Genome Evolution: Gene and Genome Duplications and the Origin of Novel Gene Functions.