Both conclusions argue that historical contingency and contemporary adaptation have likely driven differentiation between Kvichak River sockeye salmon populations, as revealed by a suite of SNPs.
Our findings highlight the need for conservation of complex population structure, because it provides resilience in the face of environmental change, both natural and anthropogenic. Several studies spanning diverse taxa suggest that the influence of these factors is often hierarchical: geography, landscape features, and vicariance may be important at larger spatial scales, whereas ecology and life history may be important at finer spatial scales (fishes: .
Disentangling the roles of geography and ecology driving population divergence and distinguishing adaptive from neutral evolution at the molecular level have been common goals among evolutionary and conservation biologists.
Using single nucleotide polymorphism (SNP) multilocus genotypes for 31 sockeye salmon () populations from the Kvichak River, Alaska, we assessed the relative roles of geography (discrete boundaries or continuous distance) and ecology (spawning habitat and timing) driving genetic divergence in this species at varying spatial scales within the drainage.
We also evaluated two outlier detection methods to characterize candidate SNPs responding to environmental selection, emphasizing which mechanism(s) may maintain the genetic variation of outlier loci.
For the entire drainage, Mantel tests suggested a greater role of geographic distance on population divergence than differences in spawn timing when each variable was correlated with pairwise genetic distances.
Marker labels have been simplified (the prefix " genotyped across 31 Alaskan populations (see Table 1 for population codes).