P3.72 Friday, Jan. 6 Evolution in the dark: Exploring the Genetic Basis of Cave Adaptation in Amphipod Populations ASPIRAS, A.C.*; PRASAD, R; FONG, D.W.; CARLINI, D.B; ANGLINI, D.R.; American University, Washington,D.C. firstname.lastname@example.org
Caves and their fauna provide excellent natural experiments with which examine evolutionary questions. Karst environments are characterized by low nutrient availability, low predation, low and constant temperatures, and little or no light and thus cave species like the amphipod Gammarus minus, tend to share characteristics such as low pigmentation, elongated limbs, and reduced or absent eyes. The evolutionary and developmental mechanisms of troglodytism has been worked out in some vertebrate models; however, to date, relatively little has be done in invertebrate models. In this study, we compare population level expression of eye development genes (hedgehog, pax6, sine oculis, and dachshund) of three population pairs of G. minus found in Greenbrier County, West Virginia. We observed significant differences in hedgehog expression between cave and surface populations, which suggests hedgehog may be a consistent target of evolution among observed population pairs. Interestingly, no differences were observed in pax6, sine oculis, and dachshund expression, despite their integral role in eye development in insects. These results provide developmental genetic support for the "hotspot" of evolution hypothesis and provide for an important comparison of adaptive mechanisms for animals in Karst environments.