Higher-fitness yeast genotypes are less robust to deleterious mutations
Higher-fitness yeast genotypes are less robust to deleterious mutations
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DOI：
10.1126/science.aay4199
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发表时间：
2019-10-25
期刊：
影响因子：
56.9
通讯作者：
Desai, Michael M.
中科院分区：
文献类型：
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作者：
Johnson, Milo S.;Martsul, Alena;Desai, Michael M.
自然选择驱使种群走向更高的适应性，但适应性和突变鲁棒性的二阶选择也会影响进化。在许多微生物系统中，递减回报上位性导致更适合的基因型适应性较低的趋势，但没有类似的鲁棒性模式是已知的。为了了解不同基因型之间的鲁棒性如何变化，我们测量了一组酵母菌株中数百个个体插入突变的适应性效应。我们发现，更适合的菌株是不太强大的：他们有较低的平均值和较高的方差的适应性效应的分布。这些差异的出现是因为许多突变在生长较快的菌株中具有更强烈的有害影响。适应度和鲁棒性之间的这种负相关性意味着鲁棒性的二阶选择将倾向于与适应度的一阶选择冲突。
Natural selection drives populations toward higher fitness, but second-order selection for adaptability and mutational robustness can also influence evolution. In many microbial systems, diminishing-returns epistasis contributes to a tendency for more-fit genotypes to be less adaptable, but no analogous patterns for robustness are known. To understand how robustness varies across genotypes, we measure the fitness effects of hundreds of individual insertion mutations in a panel of yeast strains. We find that more-fit strains are less robust: They have distributions of fitness effects with lower mean and higher variance. These differences arise because many mutations have more strongly deleterious effects in faster-growing strains. This negative correlation between fitness and robustness implies that second-order selection for robustness will tend to conflict with first-order selection for fitness.