The environment affects epistatic interactions to alter the topology of an empirical fitness landscape.
The environment affects epistatic interactions to alter the topology of an empirical fitness landscape.
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DOI：
10.1371/journal.pgen.1003426
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发表时间：
2013-04
期刊：
影响因子：
4.5
通讯作者：
Cooper VS
中科院分区：
文献类型：
--
作者：
Flynn KM;Cooper TF;Moore FB;Cooper VS
突变的适应效果可能受到其与环境、其他突变或两者的相互作用的影响。此前，我们构建了 32 ( = 25) 种基因型，其中包含前五个有益突变的所有可能组合，以修复实验室进化的大肠杆菌群体。我们发现（i）所有五种突变都对其发生的背景有益； (ii) 突变之间的相互作用驱动了收益递减型上位性，即随着基因型预期适应性的增加，上位性变得越来越拮抗； (iii) 突变组合揭示的适应性景观是平滑的，具有单一的全局适应度峰值。在这里，我们通过确定两个替代环境中相同突变之间的相互作用来研究环境如何影响上位性，这两个替代环境是从 1,920 个筛选环境中选出的，这两个环境对最衍生的基因型的适应性产生了最大的增加或减少。相互作用的一些一般特征是一致的：突变往往保持有益，而上位的总体模式是收益递减。其他功能取决于环境；特别是，当添加到特定基因型时，一些突变是有害的，这表明存在原始选择环境中不存在的拮抗相互作用。拮抗作用不是由单个突变的一致多效性效应引起的，而是由突变之间相互作用的改变引起的。我们的结果表明，了解不断变化的环境中的适应需要考虑跨环境的上位性和多效性的综合效应。有益突变的适应性效果可能取决于它们如何与其遗传和外部环境相互作用。这些相互作用的形式很重要，因为它可以改变适应性结果，选择或反对某些有益突变的组合。在这里，我们研究了大肠杆菌实验室菌株适应一个简单环境期间有利突变之间的相互作用，当该菌株在两种新环境中生长时如何改变。我们发现，健身效果受遗传和外部环境的影响很大。在一些情况下，环境的变化逆转了突变的影响，从有益突变变为有害突变，或导致有益突变的组合变得有害。我们的结果表明，复杂或波动的环境可能有利于突变的组合，这些突变的相互作用可能对外部条件不太敏感。
The fitness effect of mutations can be influenced by their interactions with the environment, other mutations, or both. Previously, we constructed 32 ( = 25) genotypes that comprise all possible combinations of the first five beneficial mutations to fix in a laboratory-evolved population of Escherichia coli. We found that (i) all five mutations were beneficial for the background on which they occurred; (ii) interactions between mutations drove a diminishing returns type epistasis, whereby epistasis became increasingly antagonistic as the expected fitness of a genotype increased; and (iii) the adaptive landscape revealed by the mutation combinations was smooth, having a single global fitness peak. Here we examine how the environment influences epistasis by determining the interactions between the same mutations in two alternative environments, selected from among 1,920 screened environments, that produced the largest increase or decrease in fitness of the most derived genotype. Some general features of the interactions were consistent: mutations tended to remain beneficial and the overall pattern of epistasis was of diminishing returns. Other features depended on the environment; in particular, several mutations were deleterious when added to specific genotypes, indicating the presence of antagonistic interactions that were absent in the original selection environment. Antagonism was not caused by consistent pleiotropic effects of individual mutations but rather by changing interactions between mutations. Our results demonstrate that understanding adaptation in changing environments will require consideration of the combined effect of epistasis and pleiotropy across environments. The fitness effect of beneficial mutations can depend on how they interact with their genetic and external environment. The form of these interactions is important because it can alter adaptive outcomes, selecting for or against certain combinations of beneficial mutations. Here, we examine how interactions between beneficial mutations favored during adaptation of a lab strain of Escherichia coli to one simple environment are altered when the strain is grown in two novel environments. We found that fitness effects were greatly influenced by both the genetic and external environments. In several instances a change in environment reversed the effect of a mutation from beneficial to deleterious or caused combinations of beneficial mutations to become deleterious. Our results suggest that a complex or fluctuating environment may favor combinations of mutations whose interactions may be less sensitive to external conditions.
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影响因子：
3.3
作者：
Hedrick, PW
通讯作者：
Hedrick, PW
影响因子：
3.3
作者：
Lalic, Jasna;Elena, Santiago F.
通讯作者：
Elena, Santiago F.
影响因子：
2.9
作者：
Alizon, S;van Baalen, M
通讯作者：
van Baalen, M
DOI：
10.6028/jres.070c.025
发表时间：
1966-01-01
期刊：
JOURNAL OF RESEARCH OF THE NATIONAL BUREAU OF STANDARDS SECTION C-ENGINEERING AND INSTRUMENTATION
影响因子：
--
作者：
KU, HH
通讯作者：
KU, HH
影响因子：
3.3
作者：
Duffy, S;Turner, PE;Burch, CL
通讯作者：
Burch, CL