Fitness Landscapes: An Alternative Theory for the Dominance of Mutation
Fitness Landscapes: An Alternative Theory for the Dominance of Mutation
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DOI：
10.1534/genetics.111.132944
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发表时间：
2011-11-01
期刊：
影响因子：
3.3
通讯作者：
Lenormand, Thomas
中科院分区：
文献类型：
--
作者：
Manna, Federico;Martin, Guillaume;Lenormand, Thomas
有害的突变往往是隐性的。一些理论，特别是费舍尔（基于选择）和赖特（基于新陈代谢）的理论，已经被提出来解释这种模式。尽管进行了长期的辩论，但这一问题仍未得到解决。这场争论集中在突变的平均优势上。然而，我们对突变之间显性系数的分布及其在不同环境中的变化也知之甚少。在这篇文章中，我们提出了一种新的方法来预测这种分布。我们的方法是基于一个表型适应景观模型。首先，我们表明，在一个非常广泛的条件（和环境）下，小的影响突变的平均优势应该是大约四分之一，只要生物体适应他们的环境可以很好地描述稳定选择的任意一组表型性状。其次，该理论可以预测突变体之间的优势系数的整体分布。因为它提供的是定量而不是定性的预测，所以这个理论可以直接与数据进行比较。我们发现，其预测的平均优势（平均优势接近0.25）同意与数据，根据一项荟萃分析的优势数据的轻度有害突变。然而，一个简单的景观模型不占主导地位的突变的大的影响，我们提供了可能的扩展这一类突变的理论。因为优势是进化理论的一个核心参数，而且这些预测是定量的，它们为广泛的应用和进一步的经验检验奠定了基础。
Deleterious mutations tend to be recessive. Several theories, notably those of Fisher (based on selection) and Wright (based on metabolism), have been put forward to explain this pattern. Despite a long-lasting debate, the matter remains unresolved. This debate has focused on the average dominance of mutations. However, we also know very little about the distribution of dominance coefficients among mutations, and about its variation across environments. In this article we present a new approach to predicting this distribution. Our approach is based on a phenotypic fitness landscape model. First, we show that under a very broad range of conditions (and environments), the average dominance of mutation of small effects should be approximately one-quarter as long as adaptation of organisms to their environment can be well described by stabilizing selection on an arbitrary set of phenotypic traits. Second, the theory allows predicting the whole distribution of dominance coefficients among mutants. Because it provides quantitative rather than qualitative predictions, this theory can be directly compared to data. We found that its prediction on mean dominance (average dominance close to 0.25) agreed well with the data, based on a meta-analysis of dominance data for mildly deleterious mutations. However, a simple landscape model does not account for the dominance of mutations of large effects and we provide possible extension of the theory for this class of mutations. Because dominance is a central parameter for evolutionary theory, and because these predictions are quantitative, they set the stage for a wide range of applications and further empirical tests.