滇东南水牛线粒体DNA控制区遗传多样性分析

 为了从母系遗传角度阐明滇东南水牛的群体遗传特征，本文采用PCR产物直接测序的方法对随机采集的35头滇东南水牛样品的线粒体DNA控制区序列进行了检测，并结合已发表的数据对所得序列进行了群体遗传和系统发育分析。结果在滇东南水牛中共检测到47个核苷酸多态位点，其中单一变异位点8个，简约信息位点39个，共定义了17种单倍型。在所分析的滇东南水牛序列中，碱基T，C，A和G的平均含量分别为28.00%，25.5%，31.7%，14.8%，单倍型多样度为0.815±0.066，核苷酸多样度为0.01134±0.00306，序列间平均核苷酸差异数是9.926，群体内遗传距离为0.011±0.002。系统发育和遗传差异分析显示：滇东南水牛与河流型水牛存在较大差异，检测的所有个体均属于沼泽型水牛mtDNA世系，但其由A和B两个支系组成，B支系又可进一步分为B1和B2两个亚支系。结果表明，滇东南水牛mtDNA遗传多样性较低，其存在两个母系血统来源，受河流型水牛基因渗入较小。

Characterizing Genetic Diversity of Diandongnan Buffalo Using mtDNA D-loop Sequences

 In order to elucidate the genetic characterization of Diandongnan buffalo, the mitochondrial DNA D loop sequence variation of 35 Diandongnan buffaloes random samples were examined by the method of PCR and direct sequencing. Combined the results with the data deposited in GenBank database as control, population genetic and phylogenetic analysis were conducted in the present study. A total of 47 polymorphic sites included 8 singleton polymorphic sites and 39 parsimony informative sites, which defined 17 mitochondrial haplotypes, were detected. The average percentage values of base composition of T, C, A and G in the sequences of Diandongnan buffaloes were 28.0%, 25.5%, 31.7% and 14.8%, respectively. The haplotype diversity, nucleotide diversity, the average number of nucleotide differences and the average genetic distance within the population were 0.815±0.066, 0.01134±0.00306, 9.926 and 0.011±0.002, respectively. Phylogenetic and genetic divergence analysis showed that there was remarkable genetic divergence between Diandongnan buffalo and river buffalo, and compared to river buffalo lineage, Diandongnan buffaloes assayed in this study belong to swamp mtDNA lineage which fell into two sublineages, viz. sublineage A and sublineage B. The sublineage B can further divided into B1 and B2 two groups. The results indicated that variations of mtDNA in Diandongnan buffalo population are low level. Moreover, Diandongnan buffalo have two maternal origins and possess less genetic admixture with river buffalo.