Lewis-Sigler Institute for Integrative Genomics
Dept. of Ecology and Evolutionary Biology
Host: Richard Mann
Title: Dissecting the molecular evolution of toxin insensitivity: insights into the constraints on adaptation.
Abstract: Despite the central role of adaptation in evolutionary biology, we remain ignorant about numerous aspects of the process, notably: What developmental, genetic, physiological and population-level factors limit the evolution of new biological traits and the rate of adaptation? How predictable are adaptive evolution outcomes? Answers to these questions are critical to our understanding of evolution and have important practical implications for how we might expect species to respond to anthropogenic changes. Yet they are difficult to address anecdotally, especially when so few traits have been dissected to the molecular level. Our approach is to examine “convergent" adaptations across distantly related species, and in particular settings in which large assemblages of species have adapted in parallel under a common selective pressure. As a case study, I will discuss our on-going work on the evolution of toxin-insensitivity of Na,K-ATPase by certain groups of insect herbivores as well as predatory insects and vertebrates. By combining high-throughput sequencing, evolutionary analyses, protein structure modeling and genome engineering, we have revealed the genetic and mechanistic basis for the convergent evolution of cardiac glycoside insensitivity in these groups, and identified factors that constrain its evolution. Beyond the insights into this specific adaptation, our work suggests a powerful new paradigm for studying the adaptive process.