Correspondence

Nature 457, 785 (12 February 2009) | doi:10.1038/457785b; Published online 11 February 2009

Evolution shapes systems, not just genes

Mark S. Blumberg1

  1. Department of Psychology, University of Iowa, Iowa City, Iowa 52242, USA
    Email: mark-blumberg@uiowa.edu

Sir

In my book, Freaks of Nature: What Anomalies Tell Us About Development and Evolution, I argue that our understanding of biodiversity and evolutionary change is enhanced by looking beyond mutations and population genetics to consider the mechanisms, constraints and biases of development. Jerry Coyne's review of my book (Nature 457, 382–383; 2009) makes it clear that he disagrees.

Coyne argues that his perspective has been fully tested and accepted as the orthodox working model of evolution. Accordingly, he thinks that development may have little to teach us about evolution.

His sharpest criticism is that I have "short-changed orthodoxy". However, over the years many committed evolutionists — including William Bateson, Gavin de Beer, Patrick Bateson, Gilbert Gottlieb, Pere Alberch, Stephen Jay Gould, Massimo Pigliucci, Robert Lickliter and Mary Jane West-Eberhard — have expressed similar misgivings about this orthodoxy. These individuals, with their deep appreciation of development, have seen the need to expand our evolutionary vision.

Contrary to Coyne's assertions, I never argue that genetics has a minor role in evolution, nor do I suggest that the evolutionary embrace of Gregor Mendel was misguided. On the contrary, in my book I repeatedly discuss the role of genes in normal and anomalous development and the capacity of genetic mutations to produce oddities.

But genes are only part of the answer. And so my argument in Freaks of Nature is that we need a more balanced approach. Throughout the book, I invoke the concept of interchangeability to explain, for example, how sex chromosomes or incubation temperature (or even both) can trigger in various species the developmental cascade of events that produce male and female.

In other words, development is a process comprising genetic and non-genetic factors, and evolution has shaped the entire system — not just the genes — to produce the diversity of life forms we see around us. From this perspective, development must have a crucial role in mediating the transmission of form and behaviour from one generation to the next.