Comparative Phylogeography Of Niviventer Confucianus And N.Fulvescens(rodentia:Muridae) In China

Comparative phylogeography has become a powerful method of revealing the differences of population genetic structure as well as historical dynamics and spatial pattern by researching closely related species that occupy similar niches and occur in sympatry.Meanwhile,we could explore the general pattern of ancient geological and climate events to the species and indicate the main factors affecting to phylogeographical structures.In this study we compared and contrasted two common rats in Niviventer—N.confucianus and N.fulvescens based on mitochondrial DNA cytochrome b sequences.We collected and sequenced 230 specimens of N.confucianus and 147 individuals of N.fulvescens from the wild all over China,besides,we also got 96 sequences from GenBank to compare the genetic diversity of N.confucianus and N.fulvescens as well as the differentiation of their geographical distribution and analyze the effect of biogeographic barrier.Finally,we assessed the reaction mechanism as two species face to same historical geographic and climate events and explore the reason.The main results show that:(1)Populations of N.confucianus were genetically slightly more differentiated than those of N.fulvescens related to N.confucianus has wider distribution range?more complex habitat and more number of glacial refuge in Quaternary Ice Age;the genetic diversity of western population within two species is greater than eastern population means that complex topographic configuration in Western China and the Quaternary glacial climate might have played an important role.(2)The phylogenetic tree of NJ?ML?BI and network showed that N.confucianus and N.fulvescens were monophyletic mutually and both species had a west-east phylogeographical structure but local branch is different.Combine with geographical barriers we found that the mountain isolation effect of N.fulvescens is stronger than N.confucianus and river isolation effect of N.confucianus is stronger than N.fulvescens for its weaker ability of wade into the water.(3)The divergence time of N.confucianus and N.fulvescens is around 4.17Mya for Qingzang movement?Kunlun-yellow river tectonic movement and the uplift of Yunnan-Kweichow Plateau.We found that two species survived in different ways through the Quaternary glaciations due to their different temperature tolerance:the eastern population of two species suffered potential population growth and expansion as well as western population of N.fulvescens,but the western population of N.confucianus maintained stable population.(4)Affected by habitat preferences and dispersal capacity,the population dispersal of N.confucianus and N.fulvescens is different.Stronger cold resistance and dispersal potential make N.confucianus spread from Siehuan by Hunan to eastern China and the other spread to northern China.But N.fulvescens prefer warm-humid environment as a consequence it spread from Yunnan by Guangxi to Southeast coastal area.By the comparative phylogeography we found that when N.confucianus and N.fulvescens faced to same historical geographic and climate events,they trended to develop similar phylogeographical structures and historical dynamics.Because of their different diffusion capacity and environmental tolerance,these two species eventually have different geographical distribution patterns.