中国地鼠线粒体DNA 16S rRNA基因序列分析及分子系统发育研究

Molecular phylogeny of Cricetulus griseus based on partial sequences of mitochondrial 16S rRNA gene analysis

目的通过克隆分析中国地鼠16S基因的部分序列,对中国地鼠16S基因的结构和功能进行初步探索和揭示。方法从GenBank中已报道的啮齿动物16S基因保守区设计一对引物,进行PCR扩增,测序。用Blastn与GenBank中七种啮齿类动物的16S基因进行序列比较,分析其碱基组成及变异情况,并用邻接法(NJ)、非加权组平均法(UPGMA)构建分子系统树,在分子水平上探讨中国地鼠和其他啮齿类动物的进化关系,对中国地鼠的种属地位进行了进一步验证。结果获得了中国地鼠线粒体16S基因的部分序列,其碱基组成A、T、C、G分别为40.5%、24.5%、18.7%、16.3%,与其他七种啮齿类动物的碱基含量相比,各碱基含量基本相似。NJ进化树表明,中国地鼠、金黄地鼠与欧洲仓鼠先聚为一支,小鼠与大鼠先聚为一支,东方田鼠、台湾田鼠与东欧田鼠先聚为一支。结论中国地鼠和金黄地鼠的亲缘关系最近,与传统的分类地位基本吻合。

Objective To observe the structure and function of 16S gene by cloning and analyzing the partial se- quence of Crivetulus griseus 16S, and to explore its molecular phylogeny. Methods According to the conservative domain of the published sequence ofl6S gene of rodent animals in GenBank, a pair of primers that could amplify Cricetulus griseus 16S gene was designed and synthesized. The sequence was compared with the published 16S genes in GenBank by Blastn. Based on the 16S rRNA sequences the molecular phylogenetic trees were constructed by neighbor-joining method,unweight- ed air-group method with arithmetic means, and the taxonomic status of Cricetulus gr/seu~ was estimated at molecular level. Results A part of sequences of 16S rRNA gene in Cricetulus gr/seus was obtained, and the A, T, C, G base average con- tents were 40. 5% ,24. 5% ,18. 7% and 16. 3%, respectively, The 16S base content was similar to that in other 6 rodent species. The neighbor-joining （N J） evolutionary tree showed that Cricetulus griseus, Mesocricetus auratus and Cricetus crice- tus had the closest phylogenetic relationship, Microtus forth, Microtus kikuchii and Microtus rossiacmeridionalis had the clo- sest phylogenetic relationship,Mus andRattus had the closest phylogenetic relationship. Conclusions Cricetulus gr/seus and Mesocricetus auratus had closest phylogenetic relationship. The evolution tree built from the homology of 16S rRNA genes of Cricetulus griseus and other 7 animal species is consistent with the traditional taxonomic results.