Animal Chauvinism

 
There's much to criticize in the field of evolutionary developmental biology or evo-devo. Some of the "theories" are little more than wide-eyed speculation. I'm thinking particularly of The Plausibility of Life by Marc Kirschner and John Gehart.

The thing that bugs me more than anything else is the attempt to create a general theory of evolution based entirely on a subset of living species; namely multicellular animals. Most proponents of evo-devo seem to be entirely unaware of the the fact that there are other species where genes are developmentally regulated.

This strange bias is spectacularly illustrated in a recent review in Nature Reviews: Genetics. The authors, Ronald Jenner and Matthew Wills, say,

Study of the model organisms of developmental biology was crucial in establishing evo–devo as a new discipline. However, it has been claimed that this limited sample of organisms paints a biased picture of the role of development in evolution. Consequently, judicious choice of new model organisms is necessary to provide a more balanced picture. The challenge is to determine the best criteria for choosing new model organisms, given limited resources.

Great! I couldn't agree more. When I used to teach this stuff I would begin with development in bacteriophage lambda where there is a beautiful example of a genetic switch. I then described development during sporulation in the bacterium Bacillus subtilis where there's a nice simple example of communication between the mother cell and the developing spore. Both of these examples made it into my textbook back in 1993.

Yeast development got a lot of play in my courses and it still does in the courses that are taught here. I would also look for examples of plant development since that's where I first learned about development as an undergraduate. We need to teach more plant development.

So, as you can imagine, I was excited to read the abstract of this paper. Jenner and Wills bemoan the fact that most of the work in the field is based on just six model organisms: Caenorhabditis elegans, Gallus gallus, Xenopus laevis, Mus musculis, Danio rerio, and Drosophila melanogaster. How right they are. The evo-devo crowd needs to expand their horizons to cover bacteria, protists, fungi, and plants.

So I eagerly read on to see which organisms they would name. Here are their choices: sea urchin, dung beetle, water flea (Daphnia), and sea anemone. All animals.

Evo-devo is never going to gain widespread respectability among evolutionary biologists unless the proponents abandon their animal chauvinism and start to recognize that development is important in four other kingdoms. [Press Release from the University of Bath]

Jenner, R.A., Wills, M.A. (2007) The choice of model organisms in evo-devo. Nat Rev Genet. 8:311-314. Epub 2007 Mar 6.