Beyond MHC: signals of elevated selection pressure on Atlantic salmon (Salmo salar) immune‐relevant loci

Using Atlantic salmon (Salmo salar) as a model system, we investigated whether 18 microsatellites tightly linked to immune‐relevant genes have experienced different selection pressures than 76 loci with no obvious association with immune function. Immune‐relevant loci were identified as outliers by two outlier tests significantly more often than nonimmune linked loci (22% vs. 1.6%). In addition, the allele frequencies of immune relevant markers were more often correlated with latitude and temperature. Combined, these results support the hypothesis that immune‐relevant loci more frequently exhibit footprints of selection than other loci. They also indicate that the correlation between immune‐relevant loci and latitude may be due to temperature‐induced differences in pathogen‐driven selection or some other environmental factor correlated with latitude.