Stages of limb development for A. sagrei
As lineages rapidly diversify, such as in the history of anoles, does their developmental-genetic architecture constrain the rate or direction of evolutionary change? In other words, could the processes controlling the production of variation, the variation that natural selection acts on, affect patterns of phenotypic evolution by generating some phenotypes more readily than others? While theoretical discussions like these have been prevalent for over a century, developmentally-based constraints were not formalized in the context of modern biology until the 1980’s, fueled by an influential paper by Maynard-Smith and colleagues and the re-synthesis of evolutionary and developmental biology. Since then evo-devologists have been testing the plausibility of developmental constraints by examining the developmental bases of traits that have independently evolved multiple times; phenotypes that have repeatedly evolved using the same mechanisms may be indicative of constraint (because the precise interpretation of these patterns and appropriate level of analysis are contentious I will leave further theoretical discussion of constraint to future conversations).
In a recent paper, for which I am the lead author, we set out to examine whether developmental constraints could have affected diversification of anole limb morphology.