Meeting Abstract
Adaptive radiation involves the diversification of a lineage into species that differ in phenotypic traits used to exploit different resources. Ecological opportunities arise when new or previously inaccessible resources are encountered or are newly explotaible following the acquisition of a key evolutionary innovation. Venom is a polygenic complex adaptive trait. Inter- and intraspecific venom variability has long been appreciated by herpetologists and toxinologists. Changes in venom composition are inherited, so have a genetic background. However, venom variability among conspecific snakes from different populations and age is also a common phenomenon, so there are other factors at play. Although the molecular mechanisms that generate this diversity remain largely elusive, recent evidence indicate that genetic and postgenomic mechanisms contribute to venom composition variability. Phenotypic venom variation is shaped by a variety of evolutionary processes, historical flukes (genetic drift and founder effects), and ecological adaptations. Separating the effects of history and chance from adaptation is a significant challenge, but is experimentally tractable. One way to deal with this reality is the quantitative comparison of phenotypic variation of traits associated with fitness across the evolutionary history of a group of species. Recent comparative venomic studies across a number of New Word snake lineages, including Agkistrodon, Sistrurus, Crotalus, Lachesis, Bothriechis, and Micrurus, will illustrate how genus-wide venom proteomic analysis may aid in the identification of global evolutionary trends within and between genera, and nodes of venom phenotypic differentiation across the phylogeny of these clades.
