Abstract: Objectives To discuss the genetic polymorphisms of the mitochondrial DNA (mtDNA) D-loop among four populations of Reed voles (Microtus fortis) in different regions of China. Methods A total of 34 specimens representing 4 populations were sequenced for the entire D-loop gene (922bp). All sequences were aligned by Clustal W software, and The neighbor-joining (NJ) phylogenetic tree was formed by the MEGA Version 3.1 software. The polymorphic site, haplotype diversity and nucleotide diversity were analyzed by Dnasp 4.0 software. Result 19 haplotypes were determined among 34 individuals, the haplotype ratio was 55.88%. The haplotype diversity and nucleotide diversity was 0.934士0.024 and 0.04334士0.00285 respectively. In reference to mtDNA D-loop sequences of Microtus kikuchii (GenBank AF348082) as a control, there were 172 genetic mutation sites, accounting for 18.66% of 922 bp sequence.The phylogenetic trees showed that 34 vole individuals clustered into two distinct branches: voles from Heilongjiang (smaller) were one branch, the other three vole populations comprised as the other branch, and in this branch, there were two sub-branches, all vole from Ningxia and some voles from Heilongjiang (lager) buildup one sub-branch, voles from Hunan and the rest voles from Heilongjiang (lager) belonged to the other sub-branch. Conclusion These findings suggested that the mtDNA D-loop in Reed voles from China existed informative variations within the four populations, there were some genetic diverse among intra- and inter-populations of Reed voles, but voles from Heilongjiang (smaller) showed more diversity from the other three populations.

Key words: Reed vole (Microtus fortis)； mitochondrial DNA (mtDNA), D-loop, genetic polymorphism