基于线粒体ND2与ND4基因探讨4种绵羊的系统发生关系

Phylogenetic Relationship of Four Kinds of Sheep Based on Mitochondrial Genes ND2 and ND4

对甘肃地区兰州大尾羊(Lanzhou fat tailed sheep)、滩羊(Tan sheep)、小尾羊(Small tailed han sheep)和藏羊(Tibetan sheep)的线粒体ND2和ND4基因进行扩增,利用生物信息学软件将扩增得到的序列与GenBank上下载的其他20个绵羊品种的ND2和ND4基因序列进行比对,再采用MEGA-X软件用邻接法(Neighbor-joining,NJ)和最大似然法(Maximum Likelihood,ML)分别构建NJ树与ML树,探讨不同绵羊种群之间的系统发生关系。结果表明:甘肃地区4种绵羊与国内外绵羊均有不同程度的亲缘关系;在NJ树中所有样本(除外群)聚为1大支,进而再分为2小支,其中2小支中大尾羊、滩羊、小尾羊和藏羊样本均有分布;而在ML树中所有样本(除外群)均聚为1支且并无分支;说明试验所选4种绵羊与这20个绵羊品种有较近的亲缘关系,也说明所采集到绵羊样本有可能与这20个亲缘关系较近的品种存在基因流。

The mitochondrial genes ND2 and ND4 of Lanzhou fat tailed sheep,Tan sheep,Small-Tailed Han sheep and Tibetan sheep in Gansu were amplified.The amplified sequences were compared with the ND2 and ND4 gene sequences of other 20 sheep varieties downloaded from GenBank by bioinformatics software.Then NJ tree and ML tree were constructed respectively with neighbor-joining (NJ) and maximum likelihood (ML) by MEGA-X software to explore the phylogenetic relationship between different sheep populations.The results showed that four kinds of sheep in Gansu had different degrees of kinship with sheep at home and abroad;in the NJ tree,all samples (except the outgroup) were clustered into one large branch,and then divided into two small branches in which the samples of these four kinds of sheep were concluded;in the ML tree,all samples (except the outgroup) were clustered into one branch without branches;it shows that the four kinds of sheep selected in the experiment have close genetic relationship with these 20 sheep breeds,and the collected sheep samples may have gene flow with these 20 sheep breeds.