EPAS1 Variations and Hematological Adaptations to High-Altitude Hypoxia in Indigenous Goats in Yunnan Province, China

The EPAS1 gene plays a central role in hypoxia adaptation in high-altitude animals. Using over 400 blood samples from goats across elevations in Yunnan (500-3500 m), this study examined hematological traits, genetic polymorphisms, and protein structure. Red blood cell (RBC) and hemoglobin (HGB) levels increased significantly with altitude (p < 0.05), reflecting improved oxygen transport. A non-synonymous SNP (g.86650 A>T, p.Gln556Leu) exhibited adaptive selection, with the T allele frequency rising at higher altitudes (p < 0.05). At 2500 m, TT genotype goats showed significantly higher RBC and HGB levels than AA genotypes (p < 0.05). Protein modeling revealed structural instability caused by the polymorphism, highlighting its role in enhancing hypoxia adaptation. These findings provide a foundation for improving high-altitude livestock genetics.