Abstract: This study was conducted to investigate whether Tibetan goat ATP6(ATP synthase F0 subunit 6) and Cytb(cytochrome b) genes had potential adaptive mutations in high altitude environments. In this study, by comparing 261 ATP6 and Cytb sequences of Tibetan goats (n=157, from 8 populations across Tibetan plateau with altitude>3 500 m) and low-altitude goats (n=104, from 50 populations across Eurasia with altitude<1 000 m), the nucleotide composition, genetic diversity, haplotype network map, and the effect of gene mutations on protein domain function were compared and analyzed. Thirty-three and 67 single nucleotide polymorphisms (SNPs) sites were identified in ATP6 and Cytb, respectively, in which, both genes contained 6 missense mutations. ATP6 m.8102A>G (Ile → Met; P=0.000 6) and Cytb m.14794A>G (Thr → Ala; P=0.007 7) were unique missense mutations in low-altitude goat populations, which formed haplotypes H27 and Ha36 that were significantly negatively related to high altitude adaptation (H27, P=0.007 0; Ha36, P=0.012 3). Further analysis speculated that the two mutations hindered the normal function of the proton transmembrane and affected the transfer of protons or electrons in OXPHOS(oxidative phosphorylation), which led to the difference in respiration efficiency between low-altitude goats and Tibetan goats. Based on the correlation analysis of polymorphism to function of mitochondrial ATP6 and Cytb coding regions, the high-altitude adaption mechanism of Tibetan goats was preliminarily explored, which provided certain insights for related research on altitude adaptability.

Key words: Tibetan goat, ATP6, Cytb, plateau adaptation