Official websites use. Share sensitive information only on official, secure websites. Correspondence , Peter T. Email: peuclide purdue. Email: wes. Local adaptation is facilitated by loci clustered in relatively few regions of the genome, termed genomic islands of divergence.
The mechanisms that create and maintain these islands and how they contribute to adaptive divergence is an active research topic. Here, we use sockeye salmon as a model to investigate both the mechanisms responsible for creating islands of divergence and the patterns of differentiation at these islands.
Previous research suggested that multiple islands contributed to adaptive radiation of sockeye salmon. We used whole genome resequencing to genotype millions of loci to investigate patterns of genetic variation at islands and the mechanisms that potentially created them.
We discovered 64 islands, including 16 clustered in four genomic regions shared between two isolated populations. Characterisation of these four regions suggested that three were likely created by structural variation, while one was created by processes not involving structural variation. Differentiation at islands was not consistently associated with established population attributes.
This is especially true for populations, ecotypes or species in the early stages of diverging, where recent or ongoing gene flow appears to homogenise most of the genome, while genomic islands display high differentiation Aeschbacher et al.
