Abstract
This study unveils the unique origins, evolution, and genetic variations of the Yangba cattle, an endangered breed in China, through a comparative genomic analysis involving 202 individuals from 21 domestic and international breeds. Genetic component analysis revealed that the Yangba cattle comprise four ancestral lineages: Eurasian taurine (18%), East Asian taurine (26%), Chinese indicine (39%), and Indian indicine (17%). Their high genetic diversity and low inbreeding coefficient set them apart significantly from mainstream commercial breeds. Gene introgression analysis indicated that the influx of genetic material from East Asian taurine has enhanced the Yangba cattle's adaptability to environmental stress, while the introgression from Chinese indicine has endowed them with unique advantages in muscle development and tissue repair. A genome-wide selection scan identified strong positive selection signals for genes such as ABCC2, which is involved in immune regulation, and NCOA3, which plays a role in growth regulation, in the Yangba cattle. This study systematically elucidates, for the first time, the composite ancestral composition and mechanisms of adaptive evolution in Yangba cattle. These findings offer critical insights into the conservation and sustainable utilization of endangered cattle resources and underscore the importance of implementing effective breeding programs.