Presenter :Erika Jackson
Mentor : William Cresko
Major : Biology
Poster 21
Chromosomal inversions have been linked to complex traits that facilitate adaptation in new environments in a small number of stud- ies. However, the generality of this pattern is still unclear. Studying the frequency of chromosomal inversions in threespine stickleback (Gasterosteus aculeatus) could provide an important case study to help us understand the role of chromosomal inversions in adaptive evolution. We focused on Alaskan and Oregon marine and freshwater stickleback populations to determine inversion frequencies between distant locations as well as between salinities in different bodies of water. We predicted that inversion allele frequency diver- gence between ocean and freshwater populations would occur if the inverted region contained genes important for adaptation to the alternative environments. We genotyped a large number of individuals for an inversion on Linkage Group XXI using polymerase chain reaction (PCR) designed to indicate alternate forms of the inversion. Our results showed that the inversion allele frequencies are highly divergent between Alaskan oceanic and freshwater populations. In addition, while Alaskan populations are geographically distant from Oregon populations, we found a similar pattern of divergence between Oregon populations in the two habitats. Our study provides ad- ditional evidence that chromosomal inversions may play an important role in adaptation to novel environments.