Phenotypic Evolution of Pigmentation Traits in Drosophila melanogaster
My thesis work involves investigating the phenotypic evolution of pigmentation traits in natural populations of Drosophila melanogaster. Pigmentation is the most striking feature of many organisms and often exhibit high levels of diversity within and between species. In addition, pigmentation may play a role in multiple adaptations and be subject to diverse selection pressures. For my dissertation, I am employing a candidate gene approach to illuminate how the melanin pathway genes pale and ebony may be contributing to variation in pigmentation traits in natural populations of Drosophila melanogaster in the United States. The pale gene encodes tyrosine hydroxylase and the ebony gene encodes N-β-alanyl dopamine synthetase and represent two key steps in the biochemical pathway leading to melanin formation in Drosophila epidermal cells. My work combines phenotypic analysis with genetic tools to uncover geographic patterns of polymorphisms in natural populations and how genetic variation may contribute to variation in body color that is potentially adaptive. This knowledge can possibly be applied to understanding how other pigmentation genes evolve and underlying mechanisms responsible for species diversification in Drosophila species and other insect species.