2.1 | Sample collection, extraction and sequencing
Tissue was collected from 28 caribou from across Canada and two caribou from Greenland between 1992 and 2015, representing all four subspecies and six Canadian Designatable Units (DUs; Figure 1 and Table S1). Samples were collected on road kills or from harvested animals by biologists or veterinarians with the British Columbia, Manitoba, and Ontario provincial governments, the Canadian federal government, the Greenland government, the Sahtú Renewable Resources Board, The Royal Ontario Museum, the University of Manitoba, and an independent consultant (See Table S1). Tissues were stored in RNA later ICE (Thermo Fisher Scientific, MA, USA). Phenol chloroform extractions were performed on three of the samples (The Pas, Snow Lake, and Ignace) using 0.2g of tissue, and eluted in Tris-ethylenediaminetetraacetic acid (TE) buffer at 100µl. The other samples were extracted using a Qiagen DNAeasy tissue extraction kit following the manufacturer’s instructions (Qiagen, Hilden, Germany). The samples were run on a Qubit fluorometer (Thermo Fisher Scientific, MA, USA) using the High Sensitivity Assay Kit and normalized to 20ng/µl at a final volume of 50µl. The DNA was shipped to The Centre for Applied Genomics (TCAG) at the Hospital for Sick Children (Toronto, Ontario) for library preparation and sequencing. The samples were each run on one lane of an Illumina HiSeq X (Illumina, San Diego, CA, USA), for a total of 30 lanes of sequencing. All raw reads will be made available on the NCBI by the time of publication.