DISSERTATION RESEARCH: Consequences of sympatry and allopatry for variation in reproductive genes of Drosophila pseudoobscura

Indiana University, Bloomington IN

Investigators

Abstract

Many factors influence mate choice in both plants and animals, including choosing a mate that will provide the best quality offspring while avoiding individuals of different species. The integration of these factors into a single choice implies that traits involved in mate selection within species could be the same traits that cause species to diverge from one another. Recently, the investigators used genetically modified Drosophila melanogaster to show that the same genes that control within species mate choice are also involved in species discrimination. This project is testing this association in a natural system, to understand how different populations accumulate changes in genes that control mate choice and species discrimination. These data will provide insight into the molecular mechanisms underlying natural variation in mate choice and the formation of reproductively isolated populations, which are important factors in understanding how new species arise over evolutionary time. The proposed research will examine DNA sequence and gene expression variation in reproductive genes in natural populations of the fruit fly Drosophila pseudoobscura, using high depth nucleotide sequencing. The experiment contrasts genetic changes that have occurred in populations that co-occur with closely related species, and thus must discriminate against them during mate choice, with changes in populations that are not exposed to other species. Analyses will assess genetic variation across all reproductive genes, as well as specifically in genes known to affect gamete competition. These variants will be associated with phenotypic data on mate choice within and between species, to differentiate genes that are important to mate choice, to species discrimination, and to both reproductive behaviors.