Study On The Molecular System Relationship And Geographical Distribution Of Chinese Apodemus Species

The genus Apodemus in rodentia is widespread and has a wide variety of species.Although they are small in size,they are widely distributed in most provinces in China.These species have a significant advantage in the size of niche and number of individuals in the small mammalian community,and they are wild vectors of a variety of animal pathogenic factors.However,there is still discrepancy on the taxonomic status and the classification of the genus Apodemus up to now.The known species and distribution profiles in China are also required to be improved..In the present study,1206 samples of the genus of Apodemus were collected by the National Institute for Communicable Disease Control and Prevention,Chinese Center for Disease Control and Prevention,and Institute of Zoology,Chinese Academy of Sciences.Mitochondrial gene including COI,Dloop,Cytb and IRBP gene from the samples in the genus of Apodemus were obtained and further analyzed using the phylogenetic method.Firstly,COI gene segment from 119 animals in the genus of Apodemus in China were sequenced.Then,delimitation of species was performed using barcoding technology and the phylogenetic tree established by Neighbour-Joining method.We found that there are at least eight species of Apodemus in China(mainland),including A.agrarius,A.chevrieri,A.peninsulae,A.latronum,A.ilex,A.draco,A.uralensis and an undefined species from Guizhou province,China.Besides,the distribution range of Apodemus species in China was determined,and we conducted a discussion about the geographical distribution of every Apodemus species.Secondly,the mitochondrial Cytb gene for other samples were analyzed together with the data from Genbank,and the systematic development of phylogenetic tree was reconstructed by Bayesian inferences.In addition,A.draco,A.ilex,A.sp and A.agrarius,A.chevrieri were divided into two groups to reconstruct the haplotype network,and the species and zoogeography relationship was also analyzed.Furthermore,based on results of the phylogenetic structure of Cytb gene,162 representative samples were used to amplify the other DNA fragments(such as IRBP and Dloop),and the Bayesian phylogenetic tree was constructed for the nuclear gene.Mitochondrial co-genes(COI,Cytb and Dloop)were linked to reconstruct the divergence time tree of each species,and the molecular divergence time of each species was observed and compared.The phylogenetic relationship of Apodemus species in China can be analyzed and determined comprehensively.The results suggested that the nuclear gene and mitochondrial gene showed similarity in the classification of the Apodemus species,and confirmed that all the species were overall valid species,including A.ilex and A.sp.These species belonged to the three major branches of the genus Apodemus,in which the A.uralensis and the Central Asian and European species of Apodemus were clustered into one branch.A.agrarius,A.chevrieri and A.peninsulae were distributed in East Asia of the Apodemus species clustered into a branch;A.latronum,A.ilex,A.draco,and an undefined species form a branch.In addition,A.semotus and A.pallipes are not included in this study,since A.semotus can be only found in Taiwan,China,and the taxonomic status of A.pallipes need to be further confirmed.In terms of divergence time,the deepest divergence time within the whole Apodemus dated to approximately 10.14Ma,and then A.uralensis occurred about 9.04Ma.The divergence time of A.agrarius and A.chevrieri was dated to approximately 2.15Ma,which was much later than that of the split of A.ilex and A.draco(about 2.48Ma).The undefined species from Guizhou province,China,A.sp.diverged from A.ilex and A.draco were at about 3.68Ma.