The effect of population bottlenecks on mutation rate evolution in asexual populations.
The effect of population bottlenecks on mutation rate evolution in asexual populations.
复制标题
种群瓶颈对无性种群突变率进化的影响。
DOI：
10.1111/jeb.12284
复制
发表时间：
2014
影响因子：
2.1
通讯作者：
Sniegowski,PD
中科院分区：
文献类型：
--
作者：
Raynes,Y;Halstead,AL;Sniegowski,PD
在没有重组的情况下，突变等位基因可以通过搭便车在种群中传播，其遗传背景中出现了有益的突变。过去十年的理论研究表明，有益突变的存活和固定概率可能会因种群规模瓶颈而严重降低。在这里，我们使用计算建模和酿酒酵母的进化实验来检查种群瓶颈是否会影响突变体适应无性种群的动态。在模拟中，我们表明种群瓶颈可以抑制有益突变的突变体搭便车，并且在较低的有益突变供应率时最有效。然后，我们将以相同有效种群规模繁殖的酵母实验种群置于三种不同的瓶颈制度下，观察到在较小的瓶颈条件下，突变子搭便车的速度明显较慢，这与我们的理论预期一致。因此，我们的结果表明，瓶颈可能是突变率进化的一个重要因素，并且在某些情况下可以稳定或至少延缓无性种群突变率的逐步上升。此外，我们的发现为理论上假设的群体瓶颈对有益突变的影响提供了第一个实验支持，并证明了研究突变体频率动力学对于理解影响适应度的突变的潜在动力学是有用的。
In the absence of recombination, a mutator allele can spread through a population by hitchhiking with beneficial mutations that appear in its genetic background. Theoretical studies over the past decade have shown that the survival and fixation probability of beneficial mutations can be severely reduced by population size bottlenecks. Here, we use computational modelling and evolution experiments with the yeastS. cerevisiaeto examine whether population bottlenecks can affect mutator dynamics in adapting asexual populations. In simulation, we show that population bottlenecks can inhibit mutator hitchhiking with beneficial mutations and are most effective at lower beneficial mutation supply rates. We then subjected experimental populations of yeast propagated at the same effective population size to three different bottleneck regimes and observed that the speed of mutator hitchhiking was significantly slower at smaller bottlenecks, consistent with our theoretical expectations. Our results, thus, suggest that bottlenecks can be an important factor in mutation rate evolution and can in certain circumstances act to stabilize or, at least, delay the progressive elevation of mutation rates in asexual populations. Additionally, our findings provide the first experimental support for the theoretically postulated effect of population bottlenecks on beneficial mutations and demonstrate the usefulness of studying mutator frequency dynamics for understanding the underlying dynamics of fitness‐affecting mutations.