Figure 3. Map of the Canadian Arctic with samples used for analysis. Outlined regions are existing subpopulations that are fully or partially in Canada. Points correspond to sampled individuals and are coloured according to genetic cluster assignment based on STRUCTURE analysis (pink = Polar Basin, green = M’Clintock Channel, orange = Arctic Archipelago, Blue = Hudson Complex). Black points represent individuals with membership <0.7 to a genetic cluster. Subpopulation abbreviations are the same as in Table 2.
Despite 90 individuals having values of less than 0.7 membership to a particular genetic cluster (black dots in Figure 3), most of the 642 individuals in our combined ddRADseq and GT-seq dataset were assigned to a single cluster. One exception was Viscount Melville (VM), which comprised individuals with high assignment probabilities to both the Polar Basin and M’Clintock Channel clusters. The self-assignment test performed by subpopulation (Table 2) suggests that few subpopulations are highly genetically distinguishable, as multiple have self-assignment rates low or near zero. The Gulf of Boothia (GB) and Southern Hudson Bay (SH) subpopulations displayed the highest self-assignment rates at 0.73 and 0.65, respectively. Our second self-assignment test shows that the genetic clusters suggested by our STRUCTURE analysis are typically more highly distinguishable than the subpopulations, with self-assignment rates >0.80 for three of the clusters (Table 3). Self-assignment was lowest for the Polar Basin cluster (0.35).
Table 3. Results for a self-assignment test performed inAssignPOP in R for the four genetic clusters suggested by our STRUCTURE analysis. Individuals with <0.7 membership to one cluster were removed from our combined GT-seq+ddRADseq dataset of 642 bears genotyped at 322 autosomal loci.