Cytb、12SrRNA基因进化速度对构建系统进化树的影响

目的]论证线粒体Cytb和12SrRNA基因不同进化速率影响构建的系统树拓扑结构。方法]从GenBank下载了蛇亚目12科15种蛇线粒体全序列,提取Cytb和12SrRNA基因序列,选用GTR＋I＋G核苷酸替代模型,基于最大似然法,用PAUP4.0软件分别构建2个基因的系统关系树。结果]在选用相同的软件、建树方法和研究物种的情况下,构建的系统树拓扑结构差异主要是因为线粒体Cytb和12SrRNA基因进化速率不同产生的。结论]在分子系统进化研究中,要针对不同的研究物种和研究目的,选择合适的基因构建系统进化树。

Effects of Evolution Rate of Cyt b and 12S rRNA Genes on Constructing Phylogenetic Trees

Objective]The aim was to prove that the mitochondrial genes of Cyt b and 12S rRNA with different evolutional rates have effects on the topological structures of phylogenetic trees.Method]The complete sequences of Cyt b and 12S rRNA from 15 species in 12 families of snakes were downloaded and extracted from GenBank,while their molecular phylogenetic trees were constructed by Maximum Likelihood(ML) method with GTR +I +G substitute model based on PAUP4.0 software.Result]With the same software,methods and species,the difference in topological structures of phylogenetic trees was mainly due to different evolutional rates of Cyt b and 12S rRNA genes.Conclusion]In studies on phylogenetic trees,aimed to different research species and purposes,phylogenetic trees should be constructed by choosing the correct and appropriate genes.