The evolution of mutation rate in finite asexual populations
The evolution of mutation rate in finite asexual populations
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DOI：
10.1534/genetics.105.046680
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发表时间：
2006-01-01
期刊：
影响因子：
3.3
通讯作者：
Godelle, B
中科院分区：
文献类型：
--
作者：
André, JB;Godelle, B
在这篇文章中，我们分析模型的突变率在无性生物的进化。有三种选择性的力量。首先，在其他条件相同的情况下，突变率较高的个体具有更大的适应性，这要归功于不准确复制DNA所节省的能量和时间。其次，作为另一面，这些个体的基因组复制错误可能会对适应性产生负面影响。第三，反过来说，如果要产生有益的突变，复制错误有潜在的好处。我们的模型描述了在三种力量作用下突变率调节因子的命运，并使我们能够预测突变率的长期演化轨迹。我们得到三个主要结果。首先，在无性繁殖中，适应和基因组保存的需要并不是进化的力量，可以将突变率稳定在一个中间的最佳状态。当适应具有重要作用时，它主要使突变率不稳定并产生强效应突变子的出现。其次，与通常认为的相反，当每个有害突变的适应度成本较弱时，具有大突变率的修饰符更有可能出现，因为复制错误的成本在延迟之后支付。第三，在小种群中，即使需要适应，突变率也总是被阻止在最低可达到的水平，因为适应的速度太慢，无法发挥重要作用。只有规模超过临界质量的种群才会看到它们的突变率受到适应需要的影响。
In this article, we model analytically the evolution of mutation rate in asexual organisms. Three selective forces are present. First, everything else being equal, individuals with higher mutation rate have a larger fitness, thanks to the energy and time saved by not replicating DNA accurately. Second, as a flip side, the genome of these individuals is replicated with errors that may negatively affect fitness. Third, and conversely, replication errors have a potential benefit if beneficial mutations are to be generated. Our model describes the fate of modifiers of mutation rate under the three forces and allows us to predict the long-term evolutionary trajectory of mutation rate. we obtain three major results. First, in asexuals, the needs for both adaptation and genome preservation are not evolutionary forces that can stabilize mutation rate at an intermediate optimum. When adaptation has a significant role, it primarily destabilizes Mutation rate and yields the emergence of strong-effect mutators. Second, in contrast to what is usually believed, the appearance of modifiers with large mutation rate is more likely when the fitness cost of each deleterious mutation is weak, because the cost of replication errors is then paid after a delay. Third, in small populations, and even if adaptations are needed, mutation rate is always blocked at the minimum attainable level, because the rate of adaptation is too slow to play a significant role. Only populations whose size is above a critical mass see their mutation rate affected by the need for adaptation.