Adapt or Perish: Evolutionary Rescue in a Gradually Deteriorating Environment.
Adapt or Perish: Evolutionary Rescue in a Gradually Deteriorating Environment.
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DOI：
10.1534/genetics.120.303624
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发表时间：
2020-10
期刊：
影响因子：
3.3
通讯作者：
Bitbol AF
中科院分区：
文献类型：
--
作者：
Marrec L;Bitbol AF
我们调查的微生物种群在逐渐恶化的环境中的进化救援，通过分析计算和随机模拟相结合。我们考虑一个在没有突变体的情况下注定要灭绝的种群，它只有在突变体充分适应新环境的情况下才能生存下来。我们发现，在环境恶化过程中出现较晚的突变体有更高的修复概率。种群的挽救概率随着承载力和突变概率的乘积的增加而呈S形增加。此外，我们发现，救援变得更有可能为较小的人口规模和/或突变概率，如果环境退化是缓慢的，这说明了环境退化的速度对人口的命运的关键影响。我们还表明，我们的主要结论在各种类型的适应性突变体中是稳健的，包括专家和通才突变体，以及模拟抗菌素耐药性进化的突变体。我们进一步表达了拯救种群的突变体的平均出现时间和不拯救种群的突变体的平均灭绝时间。我们的方法可以应用于其他情况下连续可变的适应度和人口规模，我们的分析预测是有效的弱到中等突变制度。
We investigate the evolutionary rescue of a microbial population in a gradually deteriorating environment, through a combination of analytical calculations and stochastic simulations. We consider a population destined for extinction in the absence of mutants, which can survive only if mutants sufficiently adapted to the new environment arise and fix. We show that mutants that appear later during the environment deterioration have a higher probability to fix. The rescue probability of the population increases with a sigmoidal shape when the product of the carrying capacity and of the mutation probability increases. Furthermore, we find that rescue becomes more likely for smaller population sizes and/or mutation probabilities if the environment degradation is slower, which illustrates the key impact of the rapidity of environment degradation on the fate of a population. We also show that our main conclusions are robust across various types of adaptive mutants, including specialist and generalist ones, as well as mutants modeling antimicrobial resistance evolution. We further express the average time of appearance of the mutants that do rescue the population and the average extinction time of those that do not. Our methods can be applied to other situations with continuously variable fitnesses and population sizes, and our analytical predictions are valid in the weak-to-moderate mutation regime.