Phylogenetic Evolution of Vertebrate Mitochondrial DNA

从线粒体dna编码的蛋白质中估计出的一些误导性的分子系统发育已经为人所知。为了澄清这些误导性系统发生的原因，我们进行了一些新的分析。1) ND1基因与其他线粒体基因在真动物目系统发育方面的矛盾树。为了区分由于小物种采样导致的随机误差和由于一些适应进化导致的趋同替代，我们对几种真动物和几种外群有袋动物的ND1基因进行了测序。结果表明，灵长类动物和啮齿类动物之间，或蕨类动物和外群之间的ND1发生了趋同进化。2)将七鳃鳗作为线粒体蛋白分析的外群，得到了七鳃鳗与肺鱼在脊椎动物树中的奇异树。为了弄清其原因，我们对shak进行了完整的mtDNA测序。以这些数据作为外群，得到了形态学上可接受的树，表明在七鳃鳗和/或肺脏谱系中发生了一些奇怪的事情。

Several cases of misleading molecular phylogenies estimated from mitochondrial DNA-encoded proteins have been known. In order to clarify the causes of these misleading phylogenies, we conducted several new analyses.1) ND1 gene gives contradictory tree from that estimated from other genes of mitochondria concerning phylogeny among eutherian orders. In order to distinguish stochastic error due to to small species sampling from convergent substitutions due to some adaptive evolution, we sequenced ND1 gene from several eutherian species as well as several outgroup marsupials.It turned out that convergent evolution has occurred in ND1 between primates and rodents or between ferungulates and outgroup.2) By using lamprey as an outgroup in the analysis of mitochondrial proteins, a bizarre tree is obtained in which lamprey groups with lungfish in the vertebrate tree. In order to clarify the reason of this, we sequenced complete mtDNA from shak. With this data as an outgroup, morphologically acceptable tree was obtained, demonstrating that something strange occurred in the lamprey and/or lungflsh lineages.