Genetic diversity and population structure of Tibetan sheep breeds determined by whole genome resequencing.

Tibetan sheep is one of primitive Chinese sheep breeds, which achieved the divergence about 2500 years ago in Qinghai plateau region. According to different geographic conditions, especially altitudes, Tibetan sheep evolved into different breeds. In this study, we performed whole genome resequencing of 5 representative Tibetan sheep breeds. Comparative genomic analysis showed that they can be divided into different clades with a close genetic relationship. However, some genes with common selective regions were enriched for hypoxic adaptability in different breeds living at higher altitude, including GHR, BMP15, and CPLANE1. Furthermore, breed-specific selective regions about physical characteristics, especially wool growth, were found in genes such as BSND, USP24, NCAPG, and LCORL. This study could contribute to our understanding about trait formation and offer a reference for breeding of Tibetan sheep.