GT-seq panel development
To identify potential SNPs for our GT-seq panel, we screened 411,094 SNP loci identified from ddRADseq data generated from 327 polar bears in Jensen et al. (2020). We filtered this dataset to retain loci that were successfully genotyped in ≥ 85% of individuals and had a minor allele frequency of at least 0.25. Retained loci were thinned to one SNP per 50,000 bp using the polar bear reference genome (GenBank GCA_000687225.1; Liu et al., 2014) to reduce possibility of linkage. These filters resulted in 442 SNP loci being retained (See Table S1 for full filtering workflow). To allow for sex identification, we added two SNPs previously recognized as sex-linked in polar bears (Pagès et al., 2009). We validated our GT-seq panel of 442 SNPs and designed primers as described in Supplemental Information: GT-seq Panel Development and Validation .