Sample size and distribution for brown (Rattus norvegicus) and black rats (R. rattus) collected across Haida Gwaii, BC.

Samples were either genotyped using double-digest restriction site-associated DNA sequencing (ddRAD) or genotyping-in-thousands by sequencing (GT-seq). All brown rats were genotyped at 315 SNPs, while all black rats were genotyped at 429 SNPs. Numbers in brackets indicate sample size less replicate samples. (*) These samples are referred to as “Kunghit” for the black rats. (†) These samples are referred to as “Lyell-SW” for the black rats. Haida island names are indicated in parentheses.