Collaborative research, RUI, SG: Phenotypic and genomic patterns of divergence across a young Drosophila species complex.

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This study will advance our understanding of the process of speciation, the splitting of one species into two. This process is the fundamental source of biodiversity and yet is still not well understood. This project will help us understand the genetic, behavioral, and morphological changes that allowed new species to fully differentiate from one another. The research focuses on fruit flies, which have long served as a model organism for studies of genetics. The researchers will study three species of fruit flies that diverged from a common ancestor species only in the last 5,000-16,000 years. By studying closely related species, it is possible to tease apart which genetic changes led to the original separation versus which changes happened afterwards. In particular, the project will identify what genetic differences are associated with differences in mating behavior and morphology that restrict or even prevent interbreeding between newly diverged species. The project will provide research experiences for undergraduate students at two liberal arts colleges and train them in DNA sequencing and genetic analysis. Further, the research findings will be used to train high school teachers and develop science educational workshops in upstate New York and western Massachusetts.The researchers will test the hypothesis that chromosomal inversions have caused divergence and speciation in the Drosophila athabasca species complex by testing two key predictions: 1) Chromosomal inversions contain Quantitative Trait Loci for divergent male courtship song and female mating preferences that are responsible for sexual isolation between these taxa. 2) Chromosomal inversions show greater sequence divergence compared to genomic regions outside of the inversions. This study will directly test if chromosomal inversions harbor phenotypes that cause sexual isolation and thereby instigated reduction in gene flow between nascent species, thus facilitating the process of genomic divergence and speciation. Two datasets will be collected: inter-species crosses to genetically map behavioral speciation phenotypes and population genomic data covering the entire geographical range of each behavioral species.