Monday, October 09, 2006

What has Evo-Devo ever done for us?

All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us? (In Monty Python's Life of Brian, 1976)
PZ Myers has just posted a letter by Jason Hodin replying to a review of Sean Caroll's Endless Forms Most Beautiful that appeared in the New York Review of Books (which the NYRB refused to publish). Briefly, Hodin argues that Sean Carroll has hyped the field of Evo-Devo and that the NYRB reviewers (neither of which is trained in biology, apparently), went even further and practically attributed every advance in evolutionary biology from the past 150 years to Evo-Devo. I generally agree with both charges, but I am more interested in the former. While I respect Sean Carroll contributions to the field of Evo-Devo, I do not share his enthusiasm about the magnitude of evo-devo's accomplishments.

Jason Hodin argues :
I don't mean to denigrate my field of Evo Devo, nor do I intend to suggest that no critical insights have come from it. Perhaps the most important contribution of the field is methodological.
I agree with this sentiment. I believe that Evo-Devo has indeed crystalized a novel approach to evolutionary biology that is now changing research into other kinds of phenotypic evolution. However, we should not deceive ourselves into thinking that what Gould called "a new and general theory of evolution" is already here: it isn't. Understanding how certain developmental mechanisms have evolved adds more patterns to our picture of evolution, in much the same way as a new fossil does. Don't get me wrong: I'm in love with the details of the "new natural history" of Evo-Devo. But to trully revolutionize evolutionary biology, development has to be incorporated into the mechanisms of evolution, such as mutation and selection. Our current understanding of contraints, modularity and evolvability, for example, has not yet accomplished that.