中国6个地区东方田鼠线粒体全基因组的比较与多态性位点的发掘

Comparison of mitochondrial genome and polymorphic loci exploration of Microtus fortis in 6 regions of China

设计16对引物,完成了我国6个地区东方田鼠样本线粒体全基因组的扩增和测序拼接。结果表明:东方田鼠的线粒体全基因组长度为16 303—16 312 bp。利用线粒体全基因组构建的系统进化树表明,在我国分布的东方田鼠分为3个主要的分支:广西样本、宁夏指名亚种为代表的北方样本(包括宁夏、黑龙江、吉林)、湖南长江亚种为代表的湖南福建样本。对中国6个地区84个东方田鼠野生样本的线粒体上的细胞色素b基因(cyt b)进行重测序,并与其他亚洲近缘田鼠的同源序列比对,共发现13个东方田鼠特有的SNP位点。在线粒体基因组的结构上发现南方样本(广西、湖南、福建)与北方样本(宁夏、黑龙江、吉林)在线粒体基因组轻链复制区(O_L区)的二级结构颈环上有一个3碱基(CCC→TTT)的突变。这些多态性位点可以作为今后东方田鼠样本鉴别、遗传多样性研究的重要分子遗传标记。

Sixteen pairs of primers were designed to amplify and sequence the mitochondrial genome of the Microtus fortis in 6 regions of China. The results showed that the mitoehondrial genome length of Microtus fortis was 16 303-16 312 bp. Phylogenetic tree constructed with mitochondrial genome indicated that Microtus fortis distributed in China was mainly divided into 3 major branches：Guangxi sample,the northern samples represented by Microtus fortis fortis （including Ningxia, Heilongjiang, Jilin）, and Hunan and Fujian samples represented by Microtus fortis calamorum. The cytochrome b gene （ cyt b） on mitochondrial of 84 wild Microtus fortis samples in the 6 regions of China were re-sequenced and analyzed by homologous sequence alignment with other Asian relatives of Microtusfortis, and a total of 13 unique SNP loci of Microtusfortis were found. There was a mutation of 3 base （CCC→TVF）on the stem-loop of secondary structure of the light chain replication region（OL） in the mitochondrial genome of the southern samples （ Guangxi, Hunan, Fujian ） and the northern samples （ Ningxia, Heilongjiang,Jilin）. These polymorphic loci could be used as important molecular markers for the identification and genetic diversity of Microtus fortis in the future.