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Evolutionary mechanism of vertbrate mitochondrial DNA

脊椎动物线粒体DNA的进化机制

基本信息

批准号：
11640624
负责人：
HASEGAWA Masami
金额：
$ 2.24万
依托单位：
The Institute of Statistical Mathematics
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

It is prerequisite to establish the phylogenetic relationships among organisms in the study of evolution and biodiversity. Therefore, molecular phylogenetics is of fundamental importance in evolutionary biology. In this project, we developed methods for inferring molecular phylogeny with the maximum likelihood, which has a sound statistical basis, and applied the methods in analyzing mitochondrial genome data.Extensive phylogenetic analyses of updated sequence data of mammalian mitochondrial genomes were carried out using the maximum likelihood method in order to resolve deep branchings in eutherian evolution. The divergence times in the mammalian tree were estimated by a relaxed molecular clock of the mitochondrial proteins calibrated with multiple references. A Chiroptera/Eulipotyphla (i.e., bat/mole) clade and a close relationship of this clade to Fereuungulata (Carnivora + Perissodactyla + Cetartiodactyla) were reconfirmed with high statistical significance. However, support for the monophyly of Fereuungulata relative to the Chiroptera/Eulipotyphla clade was fragile, and we suggest that the 3 branchings among Carnivora, Perissodactyla, Cetartiodactyla and Chiroptera/Eulipotyphla occurred successively in a short time period, estimated to be approximately 77 MyrBP.The Chiroptera/Eulipotyphla divergence was estimated to roughly coincide with the Cretaceous-Tertiary boundary (65 MyrBP). The monophyly of Rodentia, the Lagomorpha/Rodentia clade (traditionally called Glires), and the Afrotheria/Xenarthra clade were preferred over alternative relationships, but the supports of these clades were not strong enough to exclude other possibilities.

在进化和生物多样性研究中，建立生物之间的系统发育关系是前提。因此，分子系统发育学在进化生物学中具有重要意义。在本项目中，我们开发了具有良好统计学基础的最大似然方法来推断分子系统发育，并将该方法应用于线粒体基因组数据的分析。为了解决真温带进化中的深分支问题，我们使用最大似然方法对哺乳动物线粒体基因组更新后的序列数据进行了广泛的系统发育分析。哺乳动物树中的分歧时间是通过与多个参考文献校准的线粒体蛋白质的松弛分子时钟来估计的。重新确认了翼翅目/真足目(蝙蝠/鼹鼠)分支以及该支系与费龙目(食肉目+腹足目+头足目)的亲缘关系，具有很高的统计意义。然而，对Fereuungulata单系相对于翼手目/Eulipotyphla支系的支持是脆弱的，我们认为食肉目、周指目、Cetartiodactyla和Chiroptera/Eulipotyphla之间的3个分支在短时间内相继出现，估计约为77MyrBP。翼手目/Eulipotyphla的分歧估计大致与白垩纪-第三系界线(65MyrBP)重合。啮齿目的单系、拉格莫亚目/啮齿目分支(传统上称为Glires)和Afotheria/Xenarthra支系比替代关系更受欢迎，但这些支系的支撑力不足以排除其他可能性。