Meeting Abstract

46.3  Saturday, Jan. 5  Morphological evolution through cis-regulatory mutations at an enhancer of a single gene DAVIS, G.K.*; SILLERS, L.C.; PARIKH, P.; MCGREGOR, A.P.; ORGOGOZO, V.; DELON, I.; ZANET, J.; SRINIVASAN, D.G.; PAYRE, F.; STERN, D.L.; Princeton University; Princeton University; The College of New Jersey; Princeton University; Princeton University; Centre de Biologie du Development, Toulouse; Centre de Biologie du Development, Toulouse; Princeton University; Centre de Biologie du Development, Toulouse; Princeton University gkdavis@princeton.edu

What is the number and nature of the genetic events responsible for morphological change? Although central to evolutionary biology, in only a handful of cases has this question been answered in terms of identifying and confirming genetically the actual genes responsible for the evolution of a particular morphological difference. In fewer still have the relevant specific changes in genes been identified and understood in terms of their effects on development. Previous work has shown that expression of the gene shavenbaby (svb), a gene required for the development of larval trichomes in Drosophila, is controlled by at least three discrete cis-regulatory enhancers. It has further been shown that a loss of larval trichomes in the lineage leading to Drosophila sechellia is due to recent evolutionary changes in svb occurring in all three of these enhancers. Here we describe recent progress in delimiting and dissecting one of these enhancers�the one required for lateral trichomes�with the goal of identifying the specific nucleotide changes responsible for the absence of lateral trichomes in the larvae of Drosophila sechellia.