2.1 Sample Collection and genomic DNA extraction
Muscle tissue samples of two wild yak was collected from the Hoh Xil nature reserve of Qinghai Province and Yanchiwan nature reserve of Gansu Province in China, respectively. Moreover, we collected jugular vein blood samples from three Qinghai-Gaoyuan yak in Golmud City, China (N: 36° 24’ 8.64”, E: 94° 54’ 11.88”) (Table S1). The genomic DNA was extracted using Blood DNA Extraction kit (Aidlab Biotechnologies Co., Ltd, Beijing, China) according to the manufacturer recommendations, diluted to 10 to 100 ng/μL and kept it at -80℃ until to use.