Study On The Subgenus Eospalax Based On Mitochondrial Cytochrome B Gene Sequences

Collecting zokor's livers from eleven places in Gan su and using the method of conventional phenol to distill mtDNA, to expand, to measure the sequences, and to look up gene sequences which carries on the homologous sequences of cytochrome b gene from Genebank. Using molecular biology software CLUSTALX 1.81 to study original sequences. Using Dnasp 4.10 to study Haplotype diversity,Nucleotide diversity and Frequency of nucleotide variability.Computing nucleotide composition, transitions,transvertions, Si/Sv and Kimura's two-parameter distance by MEGA3 and DAMBE(Ver.4.2.13).The complete cytochrome b gene of Gansu zokor , Bailey′s zokor, Qin ling zokor,, Smith′s zokor and the sequences of Chinese zokor and Northeast zokor from GenBank were sequenced to study DNA polymorphism and phylogenetic relationships.Analysis of the sequence variation of cytochrome b gene indicated that there was no insertion/deletion found in cytb sequences (1,140bp).The 1,140bp cytochrome b alignment contained 386 variable sites, of which 333 were parsimony informative sites with the strongest variable in the third codon positions and less variable in the first and second codon positions.The base composition of the cytochrome b sequences was highly biased.The average percent value of G+C (38.2%) was less than that of A+T (61.8%).There was a bias of the content of A and T in the second codon position, coming up to 61.8%. The content of nucleotide G at the third position was the lowest, the average was only 1.7%, and divergence among species is 4.7～5.5%. Sequence variation analysis exhibited high transition (Si) to transversion (Sv) substitution ratios (Si/Sv=4.0),and transitions and transversions were unsaturated in the sequence of cytochorrne b gene. The transition occured between G and A, T and C. Using a structural model of the cytochrome b protein as a template, we divided cyt b sequence data for horse populations into three functional domains. There was more variance within transmembrane domain of cytochrome b.The N-terminal end of cytb gene had more informative for phylogeny analysis.Phylogenetic tree of these horse populations were reconstructed by three methods:Neighbor-joining, UPGMA and Most Parsimonious methods. We supported the opinion that Gansu zokor and Smith′s zokor were the kins and had the same ancestor. Phylogenetic analysis indicated that The prairie zokor is the quite ancient type in the evolution; Extrapolated the smith zokor and the Gansu zokor are has the common ancestor; The different place identical kind of zokor has the same blood relationship and the common ancestor.