Meeting Abstract

P1.65  Friday, Jan. 4  The roles of BMP6 and AP2 in tooth number determination in threespine stickleback GAI, L*; ELLIS, NA; MILLER, CT; Swarthmore College; Univ. of California, Berkeley; Univ. of California, Berkeley lgai1@swarthmore.edu

The overall objective of this project was to elucidate the genetic basis of naturally evolved tooth number differences in the threespine stickleback fish, Gasterosteus aculeatus. The threespine stickleback is well-suited for elucidating the genetic circuitry underlying tooth number variation, having undergone dramatic adaptive radiation as ancestral marine populations repeatedly colonized inland water bodies. Adaptive radiations are often associated with changes in trophic morphology, as populations adapt to new diets in new environments. In the threespine stickleback adaptive radiation, several trophic differences evolve upon freshwater adaptation, including increased tooth number in some freshwater populations. A recent study identified a number of quantitative trait loci (QTL) associated with tooth gain in a large forward cross between individuals from a high-toothed Paxton Lake freshwater benthic population and a low-toothed Japanese marine population. Our goal was to further elucidate the processes underlying evolved tooth gain using a combination of genetic and developmental approaches. Firstly, we hoped to determine which genomic regions are associated with tooth gain in lab-reared populations of Paxton Lake benthic stickleback. Secondly, we wished to characterize the expression patterns of candidate genes located near the peak QTL marker, as well as look for expression differences between high-toothed and low-toothed populations that could be responsible for tooth number divergence. In this presentation, I will give an overview of the findings and procedures resulting from this project.