Phylogenetic Evolution of Vertebrate Mitochondrial DNA

已经知道几个从线粒体DNA编码的蛋白质估计的误导性分子遗传学的案例。为了阐明这些错误的遗传学解释的原因，我们进行了几个新的分析：1）ND 1基因与线粒体其他基因关于真兽目遗传学的估计结果相矛盾。为了区分小种群抽样引起的随机误差和适应性进化引起的趋同替换，我们对几种真兽目动物和几种外群有袋类动物的ND 1基因进行了测序，结果表明，ND 1基因在灵长类和啮齿类动物之间以及有蹄类动物和外群动物之间发生了趋同进化。得到一个奇异树，其中七鳃鳗组与肺鱼在脊椎动物树中。为了阐明这一现象的原因，我们对该菌株的线粒体DNA进行了全序列测定。以这些数据作为外群，获得了形态学上可接受的树，表明七鳃鳗和/或肺鱼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.