This program of fellowships is a joint activity of the Directorate for Biological Sciences of NSF and the Alfred P. Sloan Foundation of New York City. The five-year program is in its third year. Eighteen two-year fellowships are offered each year for research and training in theoretical, comparative, computational, and /or experimental analyses of biological patterns and processes at the molecular level, within the framework of evolutionary change and adaptation of organisms, or in the use of molecular data to address broad evolutionary questions. Fellows are encouraged to broaden their scientific experience and perspective in molecular evolution by selecting a host laboratory where new conceptual approaches and experimental techniques can be learned. The research and training plan supported by this fellowship is entitled "the role of epistatic selection and pre-mRNA secondary structures in molecular evolution." Epistasis is the interaction among different genes or gene regions to produce a single phenotype; epistatic selection refers to selection acting on such a phenotype. Ten species of Drosophila are under study to determine if a cluster of linkage disequilibria observed in the 3' end of the first intron of the Drosophila melanogaster white locus is due to epistatic selection conserving precursor mRNA secondary structures. Empirical methods will be used to test for secondary structures with long-range pairings in the precursor m-RNA for D. melanogaster alcohol dehydrogenase. Lastly, computer simulations will be used to test alternative hypotheses explaining the observed clustering of linkage disequilibria. The null hypothesis is neutral mutation and genetic drift.
