Genome-Wide Association Study and Whole-Genome Resequencing Reveal Key lincRNA and Candidate Gene for Polled Phenotype in Yak.

Yaks are important livestock in high-altitude regions, and their polled trait can effectively improve breeding and management efficiency. In this study, whole-genome resequencing combined with a GWAS was employed to identify a significantly associated region of approximately 273.6 kb on chromosome 1 (36,313,286-36,586,879 bp) in Xueduo yaks. This region contains 1001 significant single-nucleotide polymorphism (SNP) loci and is located within a long intergenic non-coding RNA (lincRNA) region. Candidate genes EPCIP, OLIG1 and PAXBP1 adjacent to this region were identified. Among these, the PAXBP1 gene plays a crucial role in neural crest development, suggesting that it may be a core gene regulating horn development in yaks. Further analysis of Ashdan yaks (a polled breed developed from Datong yaks) indicated that the two breeds share the same candidate genes and a subset of associated genetic variants for the polled trait, suggesting a degree of genetic conservation underlying this trait across yak breeds. This study provides a theoretical basis for polled yak breeding.