Phylogenomic analyses revealed a new lineage of house mouse (Mus musculus) in Gyirong Basin of Xizang Autonomous Region, China

Abstract

In the present study, we collected 20 individuals and 12 individuals of wild mice from the Gyirong Basin of Xizang Autonomous Region in China and Sudurpashchim in Nepal. Phylogeny and genetic structure inferred from different types of genomic markers suggest that these samples all belong to Mus musculus, among which individuals from Gyirong Basin represent a new genomic lineage (named as M. m. gyirongus), and samples from Sudurpashchim represent an intermediate population between the central population and M. m. castaneus. M. m. gyirongus, along with M. m. domesticus and M. m. musculus, differentiated from the central population compactly during ∼ 272,000–251,000 years ago in the interglacial period. Three lineages all experienced continuous population decline before ∼ 70,000 years ago. Then, they underwent population fluctuations at different periods that might have been impacted by climate changes, migration history, and human activities. Genes related to the structure and function of neural synapses, reproduction and development, regulation of cell cycle and carcinogenesis, and immune response have undergone positive selection in the genome of M. m. gyirongus. The discovery of M. m. gyirongus not only helps us to better understand the evolutionary history of M. musculus, but also provides new regional resources for breeding novel laboratory mouse strains.