Lack of support for Deuterostomia prompts reinterpretation of the first Bilateria.
Lack of support for Deuterostomia prompts reinterpretation of the first Bilateria.
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DOI：
10.1126/sciadv.abe2741
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发表时间：
2021-03
期刊：
影响因子：
13.6
通讯作者：
Telford MJ
中科院分区：
文献类型：
--
作者：
Kapli P;Natsidis P;Leite DJ;Fursman M;Jeffrie N;Rahman IA;Philippe H;Copley RR;Telford MJ
后口动物群（脊索目和Xenambulacraria）可能不是彼此的近亲。双侧对称的动物（双侧对称门）被认为包括两个单系类群，原口动物（Ecdysozoa和Lophotrochozoa）和后口动物（Chordata和Xenambulacraria）。最近的分子系统发育研究并没有一致地支持后口单系。在这里，我们使用多个独立的系统基因组数据集比较了原口虫和后口虫的支持度。正如预期的那样，原生造口菌一直得到强有力的支持，特别是长而高质量的基因。然而，对后口畸形的支持总是模棱两可的，几乎不高于对paraphyletic替代品的支持。导致树重建错误的条件——不充分的模型、短的内部分支、更快的进化基因和不相等的分支长度——与支持单系后口动物的观点一致。模拟实验表明，系统误差可以解释对后口畸形的支持。双边动物和后口动物共同祖先之间的分支最多也就很短，这支持了双边动物祖先可能是后口动物的观点。我们的发现对理解早期动物进化具有重要意义。
The deuterostome animal groups (Chordata and Xenambulacraria) may not be each other’s closest relatives. The bilaterally symmetric animals (Bilateria) are considered to comprise two monophyletic groups, Protostomia (Ecdysozoa and the Lophotrochozoa) and Deuterostomia (Chordata and the Xenambulacraria). Recent molecular phylogenetic studies have not consistently supported deuterostome monophyly. Here, we compare support for Protostomia and Deuterostomia using multiple, independent phylogenomic datasets. As expected, Protostomia is always strongly supported, especially by longer and higher-quality genes. Support for Deuterostomia, however, is always equivocal and barely higher than support for paraphyletic alternatives. Conditions that cause tree reconstruction errors—inadequate models, short internal branches, faster evolving genes, and unequal branch lengths—coincide with support for monophyletic deuterostomes. Simulation experiments show that support for Deuterostomia could be explained by systematic error. The branch between bilaterian and deuterostome common ancestors is, at best, very short, supporting the idea that the bilaterian ancestor may have been deuterostome-like. Our findings have important implications for the understanding of early animal evolution.