论文标题
适应或灭亡：逐渐恶化的环境中的进化救援
Adapt or perish: Evolutionary rescue in a gradually deteriorating environment
论文作者
论文摘要
我们通过分析计算和随机模拟的结合，研究了在逐渐恶化的环境中对微生物种群的进化营救。我们认为，在没有突变体的情况下，注定要灭绝的人口，只有在足够适应新环境的突变体出现并固定的情况下才能生存。我们表明，在环境恶化期间出现的突变体具有更高的固定可能性。当承载能力和突变概率的乘积增加时，人口的救援概率随着乙状结肠形状而增加。此外，我们发现，如果环境降解较慢，则救援对于较小的人口规模和/或突变概率的可能性更大，这说明了环境退化对人口命运的迅速降低的关键影响。我们还表明，我们的主要结论在包括专家和通才的各种适应性突变体中以及对抗菌耐药性演变进行建模的突变体。我们进一步表达了挽救人口的突变体的平均外观和不挽救人口的平均灭绝时间。我们的方法可以应用于具有不断变化的健身和人口规模的其他情况，并且我们的分析预测在弱至中度突变方面是有效的。
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 only survive 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.
