Meeting Abstract

53.1  Jan. 6  Genetic origins of parallel evolution in threespine and ninespine stickleback fish SHAPIRO, M.D.*; SUMMERS, B.R.; BALABHADRA, S.; BELL, M.A.; KINGSLEY, D.M.; Univ. of Utah; Stanford Univ.; Stanford Univ.; Stony Brook Univ.; Stanford Univ. shapiro@biology.utah.edu

A longstanding question in the study of parallel evolution is whether the same gene or genes control similar adaptive phenotypes in different populations and species. Stickleback fish provide numerous opportunities to study the genetic basis of parallelisms. In particular, threespine (Gasterosteus aculeatus) and ninespine (Pungitius pungitius) sticklebacks show repeated evolution of similar adaptive traits among different populations within each genus, and these two genera also have evolved similar derived traits in parallel. Through intergeneric complementation tests, we demonstrated that at least one adaptive trait, pelvic reduction, likely evolved by changes at the Pitx1 locus in specific populations of both genera. To examine the genetic architecture of other interesting traits in Pungitius, we generated the first genome-wide linkage map for the ninespine stickleback. By aligning the new ninespine map with an existing threespine map and genome sequence, we found broad synteny between the two genera, thereby allowing direct comparisons of trait-mapping results. Genetic mapping studies revealed that sex determination and lateral plate number in ninespine sticklebacks and threespine sticklebacks are controlled by different chromosome regions. We also identified a chromosome region in a second population of ninespine sticklebacks that plays a major role in pelvic reduction and is not linked to Pitx1. Further studies using genetic and genomic resources from both genera will allow us to directly compare the chromosomal location and genetic architecture of other interesting, adaptive traits that evolved in parallel in these taxa.