Dating early animal evolution using phylogenomic data.
Dating early animal evolution using phylogenomic data.
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DOI：
10.1038/s41598-017-03791-w
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发表时间：
2017-06-15
影响因子：
4.6
通讯作者：
Wörheide G
中科院分区：
文献类型：
--
作者：
Dohrmann M;Wörheide G
有关动物辐射到其主要亚纲的地质时间框架的信息，对于了解早期动物生态和进化至关重要。不幸的是，前寒武纪的化石记录很少，其解释也存在争议。松弛的分子时钟方法提供了另一种方法来估计后生动物生命树深处的分支发生的时间。到目前为止，专门关注后生动物整体的深入分子时钟研究一直基于相对较小的数据集或主要非双边谱系(如海绵和鞭毛虫)的不完全表示，这是理解早期后生动物演化的基础。在这里，我们使用之前发表的系统基因组数据集，其中包括对所有相关群体的公平抽样，以使用贝叶斯松弛时钟方法估计早期动物进化的时间。根据我们的结果，所有非双边门，以及整个类群的比拉特里亚，在地质上相对较短的时间跨度内，在全球长期冰川开始之前(“雪球地球”；~720-635 Ma)，在一次古老的辐射中演化。重要的是，这一结果似乎对一些重要的分析变量的变化是稳健的，例如谱系间比率差异的模型和所使用的化石校准集。
Information about the geological timeframe during which animals radiated into their major subclades is crucial to understanding early animal ecology and evolution. Unfortunately, the pre-Cambrian fossil record is sparse and its interpretation controversial. Relaxed molecular-clock methods provide an alternative means of estimating the timing of cladogenesis deep in the metazoan tree of life. So far, thorough molecular clock studies focusing specifically on Metazoa as a whole have been based on relatively small datasets or incomplete representation of the main non-bilaterian lineages (such as sponges and ctenophores), which are fundamental for understanding early metazoan evolution. Here, we use a previously published phylogenomic dataset that includes a fair sampling of all relevant groups to estimate the timing of early animal evolution with Bayesian relaxed-clock methods. According to our results, all non-bilaterian phyla, as well as total-group Bilateria, evolved in an ancient radiation during a geologically relatively short time span, before the onset of long-term global glaciations (“Snowball Earth”; ~720–635 Ma). Importantly, this result appears robust to alterations of a number of important analytical variables, such as models of among-lineage rate variation and sets of fossil calibrations used.