John Maynard Smith Prize Lecture 2005

Speciation genes & selfish genes in Drosophila

Daven Presgraves

University of Rochester, Department of Biology, Rochester, NY 14627, USA


Speciation occurs through the evolution of any of several forms of reproductive isolation, including the intrinsic sterility or inviability of hybrids. These hybrid fitness problems are caused by negative epistatic interactions - new alleles that evolve in one species are sometimes incompatible with alleles at interacting loci from related species. Relatively little is known about the identity and function of such "speciation genes" or about the evolutionary forces driving their divergence. I will present results from a large, fine-scale genetic analysis of loci causing hybrid inviability in Drosophila. The first of these genes to be identified encodes Nup96, an essential protein component of the nuclear pore complex (NPC). I will show that the functional divergence of Nup96, and several other interacting Nup proteins, was driven by adaptive evolution. I will then discuss how this positive selection may be a consequence of genetic conflict mediated by the NPC.



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