Positive Selection in ASPM Is Correlated with Cerebral Cortex Evolution across Primates but Not with Whole-Brain Size
Positive Selection in ASPM Is Correlated with Cerebral Cortex Evolution across Primates but Not with Whole-Brain Size
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DOI：
10.1093/molbev/msn184
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发表时间：
2008-11-01
影响因子：
10.7
通讯作者：
Meier, Rudolf
中科院分区：
文献类型：
--
作者：
Ali, Farhan;Meier, Rudolf
大脑体积的快速增长是人类进化中的一个关键事件。异常纺锤状小头畸形相关基因（ASPM）被认为是解释人类大脑异常巨大的主要候选基因，但ASPM的作用仍然存在争议。在这里，我们使用密码子特异性模型和比较的方法来测试这个候选基因，最初确定在人黑猩猩比较。我们证明，加速进化的ASPM（ω = 4.7）在16个氨基酸位点发生在9个灵长类动物谱系的相对大脑皮层大小的重大变化。然而，ASPM的进化与相对全脑或小脑大小的重大变化无关。我们的研究结果表明，一个单一的候选基因，如ASPM可以影响大脑的一个特定组成部分，通过在几个氨基酸位点的变化跨越大型分支。我们进一步说明了使用灵长类动物的连续表型变异来严格测试与人类关键性状进化有关的候选基因的能力。
The rapid increase of brain size is a key event in human evolution. Abnormal spindle-like microcephaly associated (ASPM) is discussed as a major candidate gene for explaining the exceptionally large brain in humans but ASPM's role remains controversial. Here we use codon-specific models and a comparative approach to test this candidate gene that was initially identified in Homo-chimp comparisons. We demonstrate that accelerated evolution of ASPM (omega = 4.7) at 16 amino acid sites occurred in 9 primate lineages with major changes in relative cerebral cortex size. However, ASPM's evolution is not correlated with major changes in relative whole-brain or cerebellum sizes. Our results suggest that a single candidate gene such as ASPM can influence a specific component of the brain across large clades through changes in a few amino acid sites. We furthermore illustrate the power of using continuous phenotypic variability across primates to rigorously test candidate genes that have been implicated in the evolution of key human traits.