Molecular Evolution in Insectivora

据推测，食虫目是所有其他胎盘记忆的祖先。为了研究食虫目昆虫的分子进化，我们对食虫目鼹鼠、地鼠和森克鼠的线粒体细胞色素b基因和细胞色素氧化酶亚基II基因进行了全序列测定。用最大简约法和邻接法进行的系统发育分析表明，鼹鼠和地鼠或森科斯和人类聚为一类。这些结果表明，灵长目和食虫目有共同和更接近的祖先的可能性。不仅是系统发育树，而且碱基组成偏向、转换/颠换偏向都表明鼹鼠和地鼠有密切的亲缘关系和单系组合。此外，我们还试图利用核苷酸替换率和化石记录来估计鼹鼠和地鼠之间的分化时间。鼹鼠和地鼠之间的分化时间估计约为500万年至900万年。

It has been deduced that insectivora were the ancestors of all other placental memmals. In order to investigate the molecular evolution of insectivora, we sequenced the mitochondrial cytochrome b gene and the whole cytochrome oxidase subunit II gene from mole, shrew mole and suncus belonging to the order of insectivora. A phylogenetic analysis using the maximum parsimony method and the neighbor-joining method indicates the cluster of mole and shrew mole or suncus and human. These results suggests the probability that order Primate and order Insectivora have a common and closer ancestors. Not only phylogenetic, tree, but also base composition bias, transition/transversion bias suggest mole and shrew mole are closely related and monophyletic assemblage. Moreover, we tried to estimate the divergence time between mole and shrew mole using the rates of nucleotide substitution and fossil records. Divergence time between mole and shrew mole was estimated approximately 5-9 million years.