Dating the arthropod tree based on large-scale transcriptome data.
Dating the arthropod tree based on large-scale transcriptome data.
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DOI：
10.1016/j.ympev.2011.09.003
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发表时间：
2011-12
影响因子：
4.1
通讯作者：
P. Rehm;Janus Borner;K. Meusemann;B. V. von Reumont;Sabrina Simon;H. Hadrys;B. Misof;T. Burmester
中科院分区：
文献类型：
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作者：
P. Rehm;Janus Borner;K. Meusemann;B. V. von Reumont;Sabrina Simon;H. Hadrys;B. Misof;T. Burmester
分子序列不仅可以重建物种之间的系统发育关系，而且还可以提供近似分歧时间的信息。然而化石记录显示，大多数多细胞动物门的起源时间在寒武纪大爆发期间，少于5.4亿年前，而分子钟计算通常显示更早的时间。在这里，我们使用了一个大的多序列比对来自表达序列标签和基因组包括129个基因（37,476个氨基酸位置）和117个分类群，包括101节肢动物。我们得到了一致的发散时间估计应用放松贝叶斯时钟模型与不同的先验和多个校准点。替代率、缺失数据和模型先验的影响可以忽略不计，而时钟模型的影响显著。在交叉验证的基础上选择对数正态自相关模型。我们计算出节肢动物出现在600 mya。有蹄类（绒蠕虫）和真节肢动物的分裂约5.9亿年，Pancrustacea和Myriochelata约5.6亿年，Myriapoda和Chelicerata约5.55亿年，“甲壳纲”和六足纲约5.1亿年。内翅类昆虫出现于3.9亿年前。这些日期比大多数以前的分子钟估计要年轻得多，并且与化石记录更吻合。然而，节肢动物和其他后生动物门的前寒武纪起源仍然得到支持。我们的研究结果也证明了随机核序列的大数据集近似多细胞动物进化的时间的适用性。
Molecular sequences do not only allow the reconstruction of phylogenetic relationships among species, but also provide information on the approximate divergence times. Whereas the fossil record dates the origin of most multicellular animal phyla during the Cambrian explosion less than 540millionyearsago(mya), molecular clock calculations usually suggest much older dates. Here we used a large multiple sequence alignment derived from Expressed Sequence Tags and genomes comprising 129genes (37,476 amino acid positions) and 117taxa, including 101arthropods. We obtained consistent divergence time estimates applying relaxed Bayesian clock models with different priors and multiple calibration points. While the influence of substitution rates, missing data, and model priors were negligible, the clock model had significant effect. A log–normal autocorrelated model was selected on basis of cross-validation. We calculated that arthropods emerged ∼600mya. Onychophorans (velvet worms) and euarthropods split ∼590mya, Pancrustacea and Myriochelata ∼560mya, Myriapoda and Chelicerata ∼555mya, and ‘Crustacea’ and Hexapoda ∼510mya. Endopterygote insects appeared ∼390mya. These dates are considerably younger than most previous molecular clock estimates and in better agreement with the fossil record. Nevertheless, a Precambrian origin of arthropods and other metazoan phyla is still supported. Our results also demonstrate the applicability of large datasets of random nuclear sequences for approximating the timing of multicellular animal evolution.