Reproductive behavior is a major factor in determining male reproductive success in species with little or no parental care. However, courtship behavior exhibits substantial genetic variation within populations, despite potentially strong selection operating on it. In addition, reproductive behavior is the outcome of complex neural processes that are not well characterized in most organisms. Previous research using man-made genetic mutants has found many genes that can disrupt normal reproductive behavior in the fruit fly Drosophila melanogaster, an organism widely used in genetic research which shares many genetic mechanisms with vertebrates, including humans. However, it is not known if these same genes are the ones causing variation in courtship behavior in natural (non-mutagenized) populations. It is possible that subtle differences in the amount of product these genes are producing (mRNA) contributes to naturally-occurring variation in behavior, but this possibility has not been investigated. The goal of this project is to use microarray analysis, a technology that allows measurement of the mRNA produced from every gene in the genome simultaneously, to discover those genes associated with naturally occurring variation in behavior. Genome-wide mRNA expression will be measured in different genotypes derived from a single natural population of Drosophila, which differ with respect to patterns of male reproductive behavior. This study will allow discovery of new candidate genes and the analysis of pathways that control a complex neural process. It will also provide general insight into the contribution to natural variation of genes identified as affecting a complex trait in laboratory mutation screens.
Broader Impact Intellectual merit This project will begin to dissect genetic and molecular mechanisms that underlie natural variation in a complex behavioral trait, and which provide the raw material for evolution. It will also enable future investigations into the causes and consequences of genetic variation that segregates within populations. Finally, an understanding of the genetic basis of variation in male courtship behavior will have profound implications for theories of sexual selection, the evolution of mate choice, and the maintenance of genetic variation in traits under strong selection.
Education and development of undergraduates Two undergraduate students will participate in this research. These students will gain working knowledge of microarray technology, behavioral genetics, and evolutionary genetics, and this knowledge will be highly marketable. All undergraduates working on the project will also participate in weekly lab meetings, where they gain an understanding of the practicalities of modern research and also are exposed to the primary research literature.
