Convergence and Divergence in a Long-Term Experiment with Bacteria
Convergence and Divergence in a Long-Term Experiment with Bacteria
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DOI：
10.1086/691209
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发表时间：
2017-08-01
影响因子：
2.9
通讯作者：
Lenski, Richard E.
中科院分区：
文献类型：
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作者：
Lenski, Richard E.
适当设计的实验提供了量化进化收敛的可能性，因为收敛的复制种群的比例是已知的。在这里，我回顾了一个大肠杆菌的实验，其中12个种群是从同一个祖先菌株中建立的，并且在相同的条件下进化了近30年，超过65，000代。分歧和趋同之间的紧张关系一直是这一实验的主要焦点。我总结了竞争适应性的分析，对不同环境的相关反应，细胞形态，使用以前未开发的资源的能力，突变率，基因组变化和种群内多态性。这些分析揭示了趋同、趋异，而且往往是它们的复杂混合。复杂性包括进化变化方向的一致性与种群间持续的数量变异，以及给定性状在一个时间尺度上表现出分歧而在另一个时间尺度上表现出收敛的可能性。尽管这些复杂的情况也发生在自然界中，但实验提供了一种强有力的方法来研究进化趋同，这种方法是基于分析经历相同环境的复制谱系。
Suitably designed experiments offer the possibility of quantifying evolutionary convergence because the fraction of replicate populations that converge is known. Here I review an experiment with Escherichia coli, in which 12 populations were founded from the same ancestral strain and have evolved for almost 30 years and more than 65,000 generations under the same conditions. The tension between divergence and convergence has been a major focus of this experiment. I summarize analyses of competitive fitness, correlated responses to different environments, cell morphology, the capacity to use a previously untapped resource, mutation rates, genomic changes, and within-population polymorphisms. These analyses reveal convergence, divergence, and often a complicated mix thereof. Complications include concordance in the direction of evolutionary change with sustained quantitative variation among populations, and the potential for a given trait to exhibit divergence on one timescale and convergence on another. Despite these complications, which also occur in nature, experiments provide a powerful way to study evolutionary convergence based on analyzing replicate lineages that experience the same environment.