Assessing the root of bilaterian animals with scalable phylogenomic methods
Assessing the root of bilaterian animals with scalable phylogenomic methods
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DOI：
10.1098/rspb.2009.0896
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发表时间：
2009-12-22
影响因子：
4.7
通讯作者：
Dunn, Casey W.
中科院分区：
文献类型：
--
作者：
Hejnol, Andreas;Obst, Matthias;Dunn, Casey W.
动物关系的清晰图像是理解动物的形态和生态多样性如何随时间演变的先决条件。除其他外，acoelomorph扁形虫，Acoela和Nemertodermatida的位置，有各种动物器官系统的起源和进化的根本影响。然而，在使用一个或几个基因的系统发育研究中，它们的位置一直不一致。此外，Acoela一直是最不稳定的类群之一，在最近的动物胚胎基因组分析，同时检查来自许多物种的许多基因，而Nemertodermatida尚未在任何胚胎基因组研究中取样。这里介绍了来自生物体的新序列数据，这些生物体在先前的分析中不稳定或缺乏代表性，并与其他公开可用的数据结合进行分析。我们还设计了新的自动化显式方法来识别和选择不同物种的共同基因，并开发了高度优化的超级计算工具来重建基因序列的关系。这项工作的结果证实了最近关于动物关系的几项发现，并为其他群体的安置提供了新的支持。这些新的数据和方法强烈支持以前的建议，Acoelomorpha是姐妹分支的所有其他bilaterian动物，找到越来越少的证据，神秘的Xenoturbella内Deuterostomia的位置，并将Cycliophora与Entoprocta和Ectoprocta。这项工作突出了这些安排对后生动物进化的影响，并允许更清晰地了解远古时代的祖先形态和生活史。
A clear picture of animal relationships is a prerequisite to understand how the morphological and ecological diversity of animals evolved over time. Among others, the placement of the acoelomorph flatworms, Acoela and Nemertodermatida, has fundamental implications for the origin and evolution of various animal organ systems. Their position, however, has been inconsistent in phylogenetic studies using one or several genes. Furthermore, Acoela has been among the least stable taxa in recent animal phylogenomic analyses, which simultaneously examine many genes from many species, while Nemertodermatida has not been sampled in any phylogenomic study. New sequence data are presented here from organisms targeted for their instability or lack of representation in prior analyses, and are analysed in combination with other publicly available data. We also designed new automated explicit methods for identifying and selecting common genes across different species, and developed highly optimized supercomputing tools to reconstruct relationships from gene sequences. The results of the work corroborate several recently established findings about animal relationships and provide new support for the placement of other groups. These new data and methods strongly uphold previous suggestions that Acoelomorpha is sister clade to all other bilaterian animals, find diminishing evidence for the placement of the enigmatic Xenoturbella within Deuterostomia, and place Cycliophora with Entoprocta and Ectoprocta. The work highlights the implications that these arrangements have for metazoan evolution and permits a clearer picture of ancestral morphologies and life histories in the deep past.