Departmental Seminar: Dr. Peter Andolfatto

Event Date: 02.03.2014 Day: Monday Time: 12:00 noon Location: 601 Fairchild (New Seminar Room on the 6th floor) Event Type: Departmental

Abstract

Numerous insects have independently evolved the ability to feed on plants that produce toxic secondary compounds called cardenolides and can sequester these compounds for use in their defense. We surveyed the protein target for cardenolides, the alpha subunit of the sodium pump, Na(+),K(+)-ATPase (ATPα), in 14 species that feed on cardenolide-producing plants and 15 outgroups spanning three insect orders. Despite the large number of potential targets for modulating cardenolide sensitivity, amino acid substitutions associated with host-plant specialization are highly clustered, with many parallel substitutions. Additionally, we document four independent duplications of ATPα with convergent tissue-specific expression patterns. We find that unique substitutions are disproportionately associated with recent duplications relative to parallel substitutions. Together, these findings support the hypothesis that adaptation tends to take evolutionary paths that minimize negative pleiotropy. I will also discuss recent extensions of this work that examine the evolution of ATPα in the context of two predator-prey systems involving cardenolide defense.