A new genomic lineage of house mouse (Mus musculus) in Gyirong Basin of Xizang Autonomous Region, China (PRJCA030034)

In present study, we collected wild mice from Sudurpashchim of Nepal and Gyirong Basin of Xizang Autonomous Region of China for the first time. Phylogeny and genetic structure inferred from different types of genomic marker suggest that samples from Gyirong Basin represent a new genomic lineage of Mus musculus, and that samples from Sudurpashchim belong to intermediate population between central population and M. m. castaneus of M. musculus. The new lineage (M. m. gyirongicus), along with M. m. domesticus and M. m. musculus, differentiated from central population during ~267,000 to 227,000 years ago in interglacial period. Three lineages all experienced continuous population decline before ~70,000 years ago. Then, they underwent two times of population fluctuations at different time periods that might be attributed to climate changes, migration history and human activities. Genes related to regulation of cell cycle, reproduction and embryonic development, structure and function of neural synapses and immune response induced by pathogen infection had undergone positive selection in genome of M. m. gyirongicus since its divergence, which contributed to population maintenance and environmental adaptation of this lineage during colonization. The discovery of M. m. gyirongicus not only enable us to better understand the evolutionary history of M. musculus, but also can provide new genetic resources for breeding novel laboratory mouse strains.