A fundamental question in evolutionary developmental biology is how the genetic networks underlying morphological adaptations evolve. Limb length in Anolis lizards is an adaptive trait that promoted their diversification leading to more than 400 extant species. Despite that the tetrapod limb has been studied in great detail both by comparative anatomist as well as developmental geneticists, little is known about the genetic pathways underlying adaptive morphological differences between different species.
This study compares gene expression profiles of limb buds of two closely related Anolis lizards (the brown anole Anolis sagrei and the green anole Anolis carolinensis). To obtain a comprehensive picture of the dynamic changes in expression profiles during development, three different stages of limb development will be compared. The two axes of comparison (between two species and between three developmental stages) will provide insight into (1) which are the conserved and divergent modules in evolution and (2) which modules are sensitive to developmental timings.
This project aims to understand diversification in a developmental context by investigating an ecologically highly relevant trait, namely limb phenotype in Anolis lizards. It lays the basis for a more detailed analysis of divergent gene expression patterns among different Anolis ecomorphs. We can only truly understand evolutionary processes once we can link differences in appearance with genetic differences and the key to success lies in deciphering gene expression profiles. My study will contribute to this endeavour and will be an instructive example of linking development, ecology and evolution.