6 June 2014
Richard Palmer
Department of Biological Sciences
University of Alberta
If anything, debate continues to grow over the extent to which genes are "leaders" or "followers" in evolution. Right-left asymmetries in body form offer a particularly attractive tool for testing the prevalence of these alternate modes of evolution. A broad phylogenetic survey of asymmetry variation suggests that genes are "followers" in evolution much more commonly than most biologists expect. But, how do genes "capture" phenotypic variation? I will illustrate how learned behaviors (e.g., handed behavior), coupled with developmental plasticity (induced changes in form), can yield novel phenotypic variation – in an adaptive direction – upon which natural selection may act. I will then open a discussion of how cells might tell "right" from "left", which is an essential step in the eventual "capture" of right-sidedness or left-sidedness by genes.