西藏牦牛mtDNA ND6遗传多样性及系统进化分析  

Genetic Diversity and Phylogenetic Analysis on mtDNA ND6 of Tibetan Yaks

作　　者：海汀[1] 柴志欣[1] 张成福[2] 信金伟[2] 姬秋梅[2] 曾贤彬[1] 钟金城[1] 

机构地区：[1]西南民族大学动物遗传育种学国家民委/教育部重点实验室,四川成都610041 [2]西藏自治区农牧科学院畜牧兽医研究所,西藏拉萨850000

出　　处：《家畜生态学报》2014年第11期11-17,共7页Journal of Domestic Animal Ecology

基　　金：国家科技支撑计划(2012BAD03B02);西南民族大学研究生创新型科研项目(CX2013SZ46);西南民族大学研究生学位点建设项目(2012XWD-S071007)

摘　　要：为从分子水平上探究西藏牦牛的序列多态性、遗传多态性及其系统进化关系,对西藏15个牦牛类群150个个体的mtDNA ND6基因全序列进行了测定,确定了多态位点和单倍型数目,计算了单倍型多样性(Hd)和核苷酸多样性(Pi),并构建了分子聚类关系图和单倍型系统发育树。结果表明:西藏牦牛mtDNA ND6基因全序列长度均为528bp,T、C、A和G 4种碱基的平均比例分别为42.2%、7.6%、20.9%、29.3%,存在一定的碱基组成偏倚性。序列变异中存在转换、颠换2种核苷酸变异类型,其中转换37次,颠换2次,表现出较强的转换偏倚性。根据序列间核苷酸变异共确定7种单倍型,其中Hap_1为西藏牦牛类群的主流单倍型,其余6种单倍型为部分类群所特有。平均单倍型多样性(Hd)、平均核苷酸多样性(Pi)分别为0.2978、0.00191,揭示西藏牦牛mtDNA ND6遗传多样性较贫乏。根据遗传距离构建了分子聚类关系图,表明西藏15个牦牛类群可分为2大类;根据7种单倍型序列构建了单倍型系统发育树,表明西藏牦牛存在2个母系起源。To investigate the genetic diversity, clustering relationships and genetic differentiation of Tibetan yak （Bos grunniens） populations, the study analyzed the complete sequence of the mitochondrial DNA ND6 gene of 150 individuals from 15 yak populations to determine the polymorphic loci and the number of haplotypes calculate the haplotype diversity （Hd） and nucleotide diversity （Pi） and to construct the molecular cluster diagram and the haplotype phylogenetic tree. Results showed sequence length of all Tibetan yak mtDNA ND6 was 528 bp and mean percentages of T, C, A and G basic groups were 42.2%, 7.6%,20.9% and 29.3%,respectively, revealing certain degree of base composition bias. 37 transitions and 2 transversions were detected in the sequence variation, showing a strong bias of the conversion. Ac- cording to the variation between the sequences, there were totally 7 type single times in Tibetan yak mtDNA ND6, Hap-1 was the mainstream Tibetan yak haplotypes, and the remaining six haplotypes groups as part of the unique. The average haploid type diversity （Hd） and average nucleotide diversity （Pi） were O. 2978 and 0. 00191, indicating lower genetic diversity within Tibetan yak populations. The molecular cluster diagram constructed based on genetic distance showed 15 Tibetan yak groups could be divided into two categories. Phylogenetic trees constructed based on the seven kinds of haplotypes indicated that two maternal origin lines existed amons Tibetan yaks.

关 键 词：西藏牦牛 MTDNA ND6基因 遗传多样性 系统进化 

分 类 号：S811.6[农业科学—畜牧学]