Tempo and mode of genome evolution in a 50,000-generation experiment.
Tempo and mode of genome evolution in a 50,000-generation experiment.
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DOI：
10.1038/nature18959
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发表时间：
2016-08-11
期刊：
影响因子：
64.8
通讯作者：
Lenski RE
中科院分区：
文献类型：
--
作者：
Tenaillon O;Barrick JE;Ribeck N;Deatherage DE;Blanchard JL;Dasgupta A;Wu GC;Wielgoss S;Cruveiller S;Médigue C;Schneider D;Lenski RE
自然选择的适应取决于许多突变的速率、影响和相互作用，因此很难确定进化谱系中有益的突变比例。我们分析了来自12个大肠杆菌种群的264个完整基因组，以表征它们在50，000代以上的动态。保留祖先突变率的种群支持一个模型，其中大多数固定突变是有益的，有益突变的比例随着适应度的增加而下降，中性突变以恒定的速率积累。我们还比较了这些人口的突变积累线下进化的一个检查制度，最大限度地减少选择。非同义突变、基因间突变、插入和缺失在长期群体中的比例过高，进一步支持了大多数达到高频率的突变受到选择的青睐的推断。这些结果阐明了在适应新环境的人群中，控制基因组进化的力量平衡的变化。
Adaptation by natural selection depends on the rates, effects, and interactions of many mutations, making it difficult to determine what proportion of mutations in an evolving lineage are beneficial. We analysed 264 complete genomes from 12 Escherichia coli populations to characterize their dynamics over 50,000 generations. The populations that retained the ancestral mutation rate support a model where most fixed mutations are beneficial, the fraction of beneficial mutations declines as fitness rises, and neutral mutations accumulate at a constant rate. We also compared these populations to mutation-accumulation lines evolved under a bottlenecking regime that minimizes selection. Nonsynonymous mutations, intergenic mutations, insertions, and deletions are overrepresented in the long-term populations, further supporting the inference that most mutations that reached high frequency were favoured by selection. These results illuminate the shifting balance of forces that govern genome evolution in populations adapting to a new environment.