Department of Biological Science, Florida State University, Tallahassee, Florida 32306, USA.
Norwegian Institute for Nature Research (NINA), NO-7485 Trondheim, Norway.
Nature. 2017 Aug 24;548(7668):447-450. doi: 10.1038/nature23473. Epub 2017 Aug 9.
Mutation enables evolution, but the idea that adaptation is also shaped by mutational variation is controversial. Simple evolutionary hypotheses predict such a relationship if the supply of mutations constrains evolution, but it is not clear that constraints exist, and, even if they do, they may be overcome by long-term natural selection. Quantification of the relationship between mutation and phenotypic divergence among species will help to resolve these issues. Here we use precise data on over 50,000 Drosophilid fly wings to demonstrate unexpectedly strong positive relationships between variation produced by mutation, standing genetic variation, and the rate of evolution over the last 40 million years. Our results are inconsistent with simple constraint hypotheses because the rate of evolution is very low relative to what both mutational and standing variation could allow. In principle, the constraint hypothesis could be rescued if the vast majority of mutations are so deleterious that they cannot contribute to evolution, but this also requires the implausible assumption that deleterious mutations have the same pattern of effects as potentially advantageous ones. Our evidence for a strong relationship between mutation and divergence in a slowly evolving structure challenges the existing models of mutation in evolution.
突变使进化成为可能，但适应也受到突变变异影响的观点存在争议。如果突变的供应限制了进化，那么简单的进化假说就可以预测到这种关系，但目前还不清楚是否存在这种限制，即使存在，长期的自然选择也可能克服这些限制。量化突变与物种间表型分歧之间的关系将有助于解决这些问题。在这里，我们利用超过 50000 只果蝇翅膀的精确数据，证明了突变产生的变异、遗传变异和过去 4000 万年的进化速度之间存在出人意料的强正相关关系。我们的结果与简单的限制假说不一致，因为进化的速度相对于突变和遗传变异所能允许的速度非常低。原则上，如果绝大多数突变都是有害的，以至于不能促进进化，那么限制假说就可以得到挽救，但这也需要一个不合理的假设，即有害突变的影响模式与潜在有利的突变相同。我们在一个进化缓慢的结构中发现突变与分化之间存在强相关性的证据，挑战了进化中突变的现有模型。
