Meeting Abstract

94.4  Friday, Jan. 7  Diverse genetic mechanisms underlie pelvic reduction in ninespine sticklebacks (Pungitius pungitius) STRINGHAM, S.A.*; ALDENHOVEN, J.T.; TAMPIO, A.J.; MILLER, A.L.; LUNSFORD, A.R.; SHAPIRO, M.D.; Univ. of Utah sydney.stringham@utah.edu

Ninespine sticklebacks (Pungitius pungitius) demonstrate an incredible range of skeletal diversity among populations. This magnitude of differentiation is usually observed among different species rather than within a single species. The ninespine stickleback has emerged as an ideal model to study the genetic basis for evolutionary variation and convergence in skeletal traits as multiple freshwater populations have shown repeated evolution of similar morphological changes. One of the most dramatic skeletal changes in sticklebacks is pelvic (hind fin) loss, the developmental equivalent of hindlimb loss in tetrapods. Research in threespine sticklebacks (Gasterosteus aculeatus) has identified Pitx1 as a mediator of pelvic reduction in multiple populations, and this same gene has been implicated in a Canadian population of ninespine sticklebacks. Therefore, even though these two species are separated by more than 10 million years, the same gene is likely involved in this convergent morphological change. However, we used QTL mapping to identify two other loci, unlinked to Pitx1, that control pelvic reduction in two other populations of ninespine sticklebacks. Our results suggest that the genetic basis for pelvic loss in ninespine sticklebacks is not always simple and has likely evolved by changes at different loci in different populations. In order to narrow candidate regions and identify possible causative mutations, we will take a whole-genome re-sequencing approach to identify selective sweeps in multiple populations of sticklebacks.