RUI: Evolutionary Genetics of Sexual Conflict in Caenorhabditis

Bowdoin College, Brunswick ME

Investigators

Abstract

There are thousands of genes in the human genome. What forces have shaped the evolution of these genes? Recent research has suggested that the most rapidly evolving genes in many organisms may be driven by the intense competition and conflict that surrounds sexual reproduction. For example, females in many species will mate with more than one male in succession, which means that the sperm of different males must compete to fertilize eggs. Sperm competition is thought to result in an escalating, "three-way tug-of-war" as evolutionary conflicts are played out between the genes affecting sperm offensive abilities, sperm defensive abilities, and female control of sperm usage. This perpetual conflict surrounding fertilization success has been hypothesized to drive rapid and sustained evolutionary change, analogous to an escalating arms race. The research outlined in this proposal is designed to test the relative importance of male-male versus male-female conflict for the evolution of genes related to fertilization success in nematodes of the genus Caenorhabditis. In these species, it is possible to compare the way genes are evolving between lineages that have very different sperm competition regimes but are otherwise extremely similar to each other. Using standard techniques in molecular biology, the rates and patterns of protein evolution will be studied for two genes involved in fertilization success in these organisms.