Meeting Abstract
Plasticity allows species to respond rapidly to environmental changes and may guide future evolution (via the flexible stem model). While it’s thought that plasticity can evolve, little is known about its genetic underpinnings. Many teleost lineages have diverged along a benthopelagic axis encompassing coordinated shifts among behavior, morphology, and ecological niche. Importantly, some species exhibit significant plasticity along this axis while others do not. Previous work in our lab has identified candidate genes that underlie this phenomenon, including ptch1, a member of the Hedgehog (Hh) pathway, and crocc2. In order to test the hypothesis that these molecules mediate benthopelagic plasticity, we quantified rates of bone deposition in transgenic zebrafish in which Hh signaling and crocc2 were directly manipulated, as well as in three species of cichlids with different ptch1 and crocc2 genotypes. Hh signaling was manipulated via heatshock while crocc2 was knocked out using ENU mutagenesis. All fish were split into diet treatments mimicking benthic and pelagic feeding modes. Calcium-binding fluorochromes labeled bone at the beginning and end of each experiment. We focused on bones under high mechanical load during feeding, but also examined bones not engaged in foraging efforts as internal controls. In all, these data will serve to functionally test the relevance of candidate genes in establishing an ecologically-relevant plastic response, thus filling an important gap in the field.
