SNPs to discriminate different classes of hybrid between wild Atlantic salmon and aquaculture escapees

Many wild Atlantic salmon (Salmo salar) populations are threatened by introgressive hybridization from domesticated fish that have escaped from aquaculture facilities. A detailed understanding of the hybridization dynamics between wild salmon and aquaculture escapees requires discrimination of different hybrid classes, however markers currently available to discriminate the two types of parental genome have limited power to do this. Using a high-density Atlantic salmon SNP array in combination with pooled-sample allelotyping and an Fst outlier approach, we identified 200 SNPs that differentiated an important Atlantic salmon stock from the escapees potentially hybridizing with it. By simulating multiple generations of wild-escapee hybridization involving wild populations in two major phylogeographic lineages, and a genetically diverse set of escapees, we showed that both the complete set of SNPs and smaller sub-sets could reliably assign individuals to different hybrid classes up to the ...