Rates of Phenotypic and Genomic Evolution during the Cambrian Explosion
Rates of Phenotypic and Genomic Evolution during the Cambrian Explosion
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DOI：
10.1016/j.cub.2013.07.055
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发表时间：
2013-10-07
期刊：
影响因子：
9.2
通讯作者：
Edgecombe, Gregory D.
中科院分区：
文献类型：
--
作者：
Lee, Michael S. Y.;Soubrier, Julien;Edgecombe, Gregory D.
与5.3亿年前寒武纪大爆发期间相似的大多数现代动物形体计划（门）几乎同时出现，这是表型和基因快速创新的短暂间隔的有力证据，但这种大规模适应性辐射的确切速度和性质仍存在争议[1-12]。至关重要的是，过去（即祖先谱系）的形态进化速度可以从生物体之间的表型差异中推断出来，就像祖先谱系的分子进化速度可以从遗传差异中推断出来一样。本文采用贝叶斯[14]和最大似然[15]系统发育时钟方法，对寒武纪和今天最多样化的门节肢动物的广泛解剖学[16]和基因组[17]数据集进行了分析。假设节肢动物起源于埃迪卡拉纪，在寒武纪大爆发期间，与显生宙的所有后续部分相比，表型进化快了4倍，分子进化快了5.5倍。这些快速的进化速度对节肢动物精确年龄的假设是有力的。令人惊讶的是，即使节肢动物的辐射完全压缩到寒武纪（类似于542兆年[Ma]）或压缩到低温纪（类似于650兆年），这些快速的早期速率也没有实质性的变化。最快的推断速率仍然与自然选择的进化和来自活生物体的数据相一致，有可能解决“达尔文困境”。然而，寒武纪大爆发期间的进化是不寻常的（与随后的显生宙相比），在许多谱系中都出现了快速的进化速度。
The near-simultaneous appearance of most modern animal body plans (phyla) similar to 530 million years ago during the Cambrian explosion is strong evidence for a brief interval of rapid phenotypic and genetic innovation, yet the exact speed and nature of this grand adaptive radiation remain debated [1-12]. Crucially, rates of morphological evolution in the past (i.e., in ancestral lineages) can be inferred from phenotypic differences among living organisms just as molecular evolutionary rates in ancestral lineages can be inferred from genetic divergences [13]. We here employed Bayesian [14] and maximum likelihood [15] phylogenetic clock methods on an extensive anatomical [16] and genomic [17] data set for arthropods, the most diverse phylum in the Cambrian and today. Assuming an Ediacaran origin for arthropods, phenotypic evolution was similar to 4 times faster, and molecular evolution similar to 5.5 times faster, during the Cambrian explosion compared to all subsequent parts of the Phanerozoic. These rapid evolutionary rates are robust to assumptions about the precise age of arthropods. Surprisingly, these fast early rates do not change substantially even if the radiation of arthropods is compressed entirely into the Cambrian (similar to 542 mega-annum [Ma]) or telescoped into the Cryogenian (similar to 650 Ma). The fastest inferred rates are still consistent with evolution by natural selection and with data from living organisms, potentially resolving "Darwin's dilemma." However, evolution during the Cambrian explosion was unusual (compared to the subsequent Phanerozoic) in that fast rates were present across many lineages.