MOLECULAR EVOLUTIONARY GENETICS OF HAWAIIAN DROSOPHILA CHORION

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This is a continuing program of research whose goal is to address some of the theories on the evolution and rapid Drosophila speciation events that have occurred in Hawaii. It has been postulated that the numerous speciation events in Hawaiian Drosophila are mostly a result of repetitive founder events combined with the repetitive radiation events towards forms adapted to a plethora of empty ecological niches in each emerging volcanic island. We aim to test if the beta lineages of the planitibia subgroup of the picture-wingeds have gone through several founder events as opposed to the alpha sub-lineage by comparing the DNA divergence rates of the lineages, the shape of the curves generated by the distributions of pairwise differences within populations, their variances, the ratio of the level of polymorphisms over divergence for each population, and the strength of their codon biases. In addition, the levels of polymorphisms shared between founder species and their closest ancestors will be estimated. The level of polymorphisms shared between presumable incipient species within an island will be compared to that of sibling species that are believed to have speciated by the same process. We are collecting the necessary data by the PCR-mediated amplification of DNA fragments extracted from wild-caught flies that correspond to two chorion genes with rapid divergence rates and apparent neutral evolution. The neutral model of molecular evolution will be tested for these fragments.