Ozawa T, Hayashi S, Mikhelson V M
Department of Earth and Planetary Sciences, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-01, Japan.
J Mol Evol. 1997 Apr;44(4):406-13. doi: 10.1007/pl00006160.
Here we report DNA sequences from mitochondrial cytochrome b gene segments (1,005 base pairs per species) for the extinct woolly mammoth (Mammuthus primigenius) and Steller's sea cow (Hydrodamalis gigas) and the extant Asian elephant (Elephas maximus), the Western Indian manatee (Trichechus manatus), and the hyrax (Procavia capensis). These molecular data have allowed us to construct the phylogeny for the Tethytheria. Our molecular data resolve the trichotomy between the two species of living elephants and the mammoth and confirm that the mammoth was more closely related to the Asian elephant than to the African elephant. Our data also suggest that the sea cow-dugong divergence was likely as ancient as the dugong-manatee split, and it appears to have been much earlier (22 million years ago) than had been previously estimated (4-8 million years ago) by immunological comparison.
在此，我们报告了已灭绝的猛犸象（Mammuthus primigenius）、斯特勒海牛（Hydrodamalis gigas）以及现存的亚洲象（Elephas maximus）、西印度海牛（Trichechus manatus）和蹄兔（Procavia capensis）线粒体细胞色素b基因片段（每个物种1005个碱基对）的DNA序列。这些分子数据使我们能够构建非洲兽总目的系统发育树。我们的分子数据解决了现存两种大象与猛犸象之间的三分法问题，并证实猛犸象与亚洲象的亲缘关系比与非洲象更近。我们的数据还表明，海牛与儒艮的分化可能与儒艮和海牛的分化一样古老，而且似乎比之前通过免疫比较估计的时间（400 - 800万年前）要早得多（2200万年前）。
