野牦牛线粒体基因组序列测定及其系统进化

野牦牛属高寒地区的特有物种,是我国最珍贵的野生动物遗传资源之一,已被列为国家一级重点保护动物。对野牦牛mtDNA进行全序列测定和结构分析,并基于线粒体基因组序列对其系统发生进行了探讨。结果表明:(1)野牦牛线粒体基因组全序列的大小为16 322 bp,整个基因组由37个编码基因和D-loop区组成;22个tRNA基因序列长度为1 524 bp、2个RNA基因序列长度为2 528 bp、13个编码蛋白基因序列长度为11420 bp、D-loop区长度为892 bp。基因组中无间隔序列,基因间排列紧密,基因内无内含子。(2)野牦牛具有较丰富的遗传多样性。(3)分子系统发生关系显示牦牛为牛亚科中的一个独立属,即牦牛属(Poephagus),牦牛属包括家牦牛(Poephagus grunniens)和野牦牛(Poephagus mutus)2个种。野牦牛线粒体基因组全序列的获得和结构解析对研究牦牛的起源、演化和分类,以及野牦牛遗传资源的保护、开发和利用均具有重要的理论和实际意义。

Mitochondrial complete genome sequencing and phylogenetic research on wild yak

Wild yak(Bos grunnients mutus), endemic Bovidae species in alpine region, is one of the most precious wild animal genetic resources in China. It has been listed as national protected animal. Our study analysed the whole sequence composition of mtDNA of wild yak and explored yak''s taxonomic status. The results showed that the size of complete Mitochondrial genome of wild yak is 16 322 bp that include 22 tRNA genes, 2 rRNA genes, 13 protein coding genes and one D-loop region. The length of two rRNA genes, 22 tRNA genes, 13 code-length protein sequences and D-loop were 2528 bp, 1524 bp, 11420 bp and 892 bp respectively. The sequence has the characterization of no interval sequence, and the gene order is close with no intron. Wild yak have abundant genetic diversity.The phylogenetic trees constructed with whole mitochondrial genome sequences of wild yak, domestic yak, Zebu cattle, Cattle, Sheep, Chiru, Aoudad, Water buffalo, American bison, White rhinoceros, Greater Indian rhinoceros and Horse showed that the wild yak and domestic yak clustered firstly, and then meet with the American bison, followed with zebu/cattle and water buffalo.The yak is a species of the subfamily-Poephagus, and the domestic yak(Poephagus grunniens) and wild yak(Poephagus mutus) are two different species in the yak. The study has the great theoretical and practical significance for yak''s origin, evolution and classification. At the same time, it is helpful to protection and utilization of wild yak genetic resources.