Escherichia coli rpoB mutants have increased evolvability in proportion to their fitness defects.
Escherichia coli rpoB mutants have increased evolvability in proportion to their fitness defects.
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DOI：
10.1093/molbev/msq024
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发表时间：
2010-06
影响因子：
10.7
通讯作者：
Lenski RE
中科院分区：
文献类型：
--
作者：
Barrick JE;Kauth MR;Strelioff CC;Lenski RE
进化性是指生物体或种群产生适应性增强的后代的能力。模拟和比较研究表明，进化性可能因个体而异，并确定了可以促进进化性的遗传结构特征。然而，人们对生物有机体的进化能力在其历史上的每个突变步骤中沿着谱系通常如何变化的情况知之甚少。在维持有害突变时，进化性可能会增加，因为适应度景观中有许多补偿路径可以提升相同的适应度峰值，或者因为向新峰值的转变成为可能。我们使用遗传标记分歧轨迹来参数化和比较一系列大肠杆菌突变体在多个时间尺度上的进化性（定义为由测试基因型引发的进化群体实现的适应性增加）。每个突变体与常见祖先菌株的不同之处在于 rpoB 基因的突变，该基因编码 RNA 聚合酶的 β 亚基。具有较大适应性缺陷的菌株在其直接突变邻域中可获得的有益突变以及在穿越多个有益突变的进化路径上的整合方面按比例更具进化性。我们的结果建立了对具有给定有害适应性效应的突变如何影响进化性的定量预期，因此它们将为未来研究针对其他细胞过程的有害、中性和有益突变如何影响微生物的进化潜力提供信息。
Evolvability is the capacity of an organism or population for generating descendants with increased fitness. Simulations and comparative studies have shown that evolvability can vary among individuals and identified characteristics of genetic architectures that can promote evolvability. However, little is known about how the evolvability of biological organisms typically varies along a lineage at each mutational step in its history. Evolvability might increase upon sustaining a deleterious mutation because there are many compensatory paths in the fitness landscape to reascend the same fitness peak or because shifts to new peaks become possible. We use genetic marker divergence trajectories to parameterize and compare the evolvability—defined as the fitness increase realized by an evolving population initiated from a test genotype—of a series of Escherichia coli mutants on multiple timescales. Each mutant differs from a common progenitor strain by a mutation in the rpoB gene, which encodes the β subunit of RNA polymerase. Strains with larger fitness defects are proportionally more evolvable in terms of both the beneficial mutations accessible in their immediate mutational neighborhoods and integrated over evolutionary paths that traverse multiple beneficial mutations. Our results establish quantitative expectations for how a mutation with a given deleterious fitness effect should influence evolvability, and they will thus inform future studies of how deleterious, neutral, and beneficial mutations targeting other cellular processes impact the evolutionary potential of microorganisms.
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影响因子：
64.8
作者：
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通讯作者：
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影响因子：
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作者：
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通讯作者：
JOLICOEUR, P