Cryptic genetic variation promotes rapid evolutionary adaptation in an RNA enzyme
Cryptic genetic variation promotes rapid evolutionary adaptation in an RNA enzyme
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DOI：
10.1038/nature10083
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发表时间：
2011-06-02
期刊：
影响因子：
64.8
通讯作者：
Wagner, Andreas
中科院分区：
文献类型：
--
作者：
Hayden, Eric J.;Ferrada, Evandro;Wagner, Andreas
隐性变异是由表型对突变的稳健性引起的(1)。隐性变异在给定的遗传或环境背景下对表型没有影响，但在突变或环境变化后可能会产生影响（2-5）。由于自然选择的进化适应需要表型变异，表型揭示的隐性遗传变异可能促进进化适应（6-8）。这是可能的，如果隐性变异恰好预先适应或“预期”(9)到一个新的环境，因此一旦发现是有利的。然而，这种促进隐性变异的作用尚未得到证实，部分原因是大多数相关工作集中在整个生物体的复杂表型上，其遗传基础尚未完全了解。在这里，我们发现积累了隐变的RNA酶群体比没有隐变的群体更快地适应新的底物。对我们在基因型空间中进化的RNA群体的详细分析表明，隐性变异允许群体探索新的基因型，这些基因型仅在新环境中具有适应性。我们的观察表明，隐型变异包含了预先适应环境变化的新基因型。我们的研究结果强调了鲁棒性和上位性在适应性进化中的积极作用（10,11）。
Cryptic variation is caused by the robustness of phenotypes to mutations(1). Cryptic variation has no effect on phenotypes in a given genetic or environmental background, but it can have effects after mutations or environmental change(2-5). Because evolutionary adaptation by natural selection requires phenotypic variation, phenotypically revealed cryptic genetic variation may facilitate evolutionary adaptation(6-8). This is possible if the cryptic variation happens to be pre-adapted, or "exapted"(9), to a new environment, and is thus advantageous once revealed. However, this facilitating role for cryptic variation has not been proven, partly because most pertinent work focuses on complex phenotypes of whole organisms whose genetic basis is incompletely understood. Here we show that populations of RNA enzymes with accumulated cryptic variation adapt more rapidly to a new substrate than a population without cryptic variation. A detailed analysis of our evolving RNA populations in genotype space shows that cryptic variation allows a population to explore new genotypes that become adaptive only in a new environment. Our observations show that cryptic variation contains new genotypes pre-adapted to a changed environment. Our results highlight the positive role that robustness and epistasis can have in adaptive evolution(10,11).