The Study On Genetic Differentiation Of Myospalax Cansus In Liupan Mountain

The Gansu zokor is the rodent(Rodentia)of Myospalacinae which distrituted in Gansu province and Ningxia Liupan Mountain of Loess Plateau and lives underground all the year round.The zokors' excavation behaviors such as foraging consume a lot of energy,so that their migrations for long distance are limited,and the diffusion rate is obviously lower than that of ground mouse.This restricts gene communications among populations to a certain extent,resulting in a higher differentiation pattern among populations.Because of its special lifestyle and low diffusion,the zokors have formed different adaptive evolution level to the underground life,prompting its body structure to adapt to the tunnel system.The subterranean mice may face a series of survival stresses,such as lack of food resources,energy consumption and hypoxia,which cause the morphology,physiology and behavior of underground mice become convergent to adapt to the same survival pressure.Although some studies have been conducted on the genealogical relationships of Gansu zokors,the phylogenetic relationships of Gansu zokors in Ningxia Liupan mountain are still unclear.In order to clarify the differentiation of populations of Gansu zokors in Liupan mountain,it is necessary to study the genertic diversity of Gansu zokors.In this study,we selected 22 skull morphology indexes of Gansu zokors of 6 geographical populations in Liupan mountains to analyze their morphological variation based on principal component analysis and cluster analysis,and revealed the morphological variation level of different populations of Gansu zokors.At the same time,we obtained three mitochondrial gene sequences such as D-loop,Cytb and ND4,and we constructed the phylogenetic tree by using the maximum likelihood(ML),Neighbor-joining distance method(NJ)and unweighted pairgroup method with arithmetic means(UPGMA)based on the Tamura-nei model.The principal component analysis based on skull morphological features of Gansu zokor showed that the cumulative contribution rate of the first three ingredients of male was 80.263%,and the female was 70.698%.The indicators which had the largest contributions for variance in populations reflected the skull size such as cranial length,base length and cranial base,and indicated the volume of auditory bulla such as the length and the bredth of auditory bulla.The systemic clustering results showed that the Gansu zokors of 6 populations were clustered into two big groups,one group was the Haiyuan and the Xiji,the other was the population of Longde,Jingyuan,Yuanzhou and Pengyang.The latter was divided into two small groups,one group was Longde and Jingyuan,the other was Yuanzhou and Pengyang population.The study on the sequences of D-loop,Cytb and ND4 of Gansu zokor showed that the differentiation of Gansu zokors in Liupan mountain was obviously among 6 populations,and the results showed a significantly positive correlation relationship between the genetic distance and geographic distance of populations.The topology structure of three phylogenetic tree based on the combination of gene sequences were basically the same as each other.The results showed that 6 geographical populations were clustered into 3 stable branches.Pengyang and Jingyuan populations were clustered together,and Guyuan and Longde populations were clustered together.Haiyuan and Xiji populations were clustered into one.A comprehensive analysis showed that at both morphological and molecular level there were large differences among 6 different geographical populations of Gansu zokors,and there showed a significant geographical distribution pattern and the populations had high genetic diversity.Distance isolation and geographical isolation may be the main cause of genetic differences among populations.In this study,the analysis of mitochondrial DNA sequences and morphological data of Gansu zokors were used to reveal the genetic evolutionary relationships of Gansu zokors in Liupan mountain of Ningxia.