Inferring The Evolution Of Subspecies Of The Chinese House Mice From The Autosomal,Chromosome Y And Mitochondrial Sequences

The house mice (Mus musculus) is one kind of small rodent. Many human diseases could be found in them too, owing to the feature of being commensal with humans. Meanwhile, the homological proportion between house mice and humans could be up to93%. Nowadays, house mice, as an important model animal, has been applied to a variety of fields, including biology, medicine and the researches of complex traits which needs to use the affluent genetic diversities as much as possible. About one decade ago, the research showed that, in China, the mice belonging to M. m. castaneus mostly live on the south of the Changjiang River, while mice belonging to M. m. musculus on the north of the Huanghe River. But we have less knowledge about such questions as the immigration and genetic evolution of the two subspecies, gene introgression and so forth.The sampling regions of this study covered13provinces and36localities, which are related to all of the7zoological regions in China. The study was performed to investigate the distribution and the evolution of Chinese wild house mice via the following four approaches:(1) Reconstructing and analyzing the haplotypes based on the7tag SNPs detected in the coding region of mitochondria, to clear again the distribution of the two subspecies in China.(2) Sequencing the control region of mitochondria to decipher the maternal genetic structure among both the intro-populations and the individuals.(3) Sequencing one segment located in one intron of a Y-linked gene, Jarid1d, in order to detect the feature of the paternal genetic structure of Chinese wild mice.(4) Illuminating the affairs of recombination in the autosomes between the subspecies in China, using the sequences of5linked genes.Firstly,9haplotypes with two major ones, H1and H9, were constructed using the7tag SNPs, which could be divided into two groups belonging to the two subspecies separately, M. m. castaneus and M. m. musculus. H1accounted for26.79%in all the samples, and H9at45%. The proportions of the9haplotypes differented greatly in Shanghai, Shandong, Jiangsu and other provinces. Interestingly, Shanghai, a typical southern city in China, had a dominant M. m. musculus haplotype distribution, whereas Chongmin Island with the dominant subspecies, M. m. castaneus. Secondly, the phylogenic tree showed that M. m. musculus is basal, while there is a close relation between M. m. castaneus and M. m. domesticus. And the tree could be divided into5clades. In China, including Shanghai, the dominant subspecies was, however, the trend that M. m. castaneus introgressed into M. m. musculus happended more possibly, which could be owing to the high-density sampling in Shanghai and the special geological location and economic status of Shanghai. Clade4was shared by the southeast areas, Yunnan and Guangxi, and other localities, which illustrated that the immigration of house mice happended very widely. Thirdly, all the chromosome Y of Chinese wild mice, including the south subspecies, had been replaced by M. m. musculus. Lastly, all the23samples recombinated, and6of them had bi-recombination, which stated that the phenomenon of introgression occurred very remarkably.This paper illuminated the distribution and the evolution of the subspecies in China from the maternal, the fraternal and the parent aspects, which would lay a solid foundation for the further research about the house mice.