Surfing on the seascape: Adaptation in a changing environment
Surfing on the seascape: Adaptation in a changing environment
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DOI：
10.1111/evo.13784
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发表时间：
2019-06-28
期刊：
影响因子：
3.3
通讯作者：
Koetzing, Timo
中科院分区：
文献类型：
--
作者：
Trubenova, Barbora;Krejca, Martin S.;Koetzing, Timo
环境在不同的时间尺度上不断变化，为了生存，物种需要不断适应。这些物种能否成功避免灭绝是一个重大的进化问题。利用强选择下突变受限种群适应的多位点进化模型，研究了环境波动频率对适应的影响。我们的结果依赖于“自适应行走”的近似，并使用进化计算理论中的数学方法来研究波动频率、环境相似性和有助于适应的基因座数量之间的相互作用。首先，我们假设一个线性加法适应度函数，但后来将我们的结果推广到包括几种类型的上位性。我们发现，频繁的环境变化阻止了人口达到健康峰值，但它们也可能防止在单一环境变化后发生的大规模健康损失。因此，种群可以在广泛的条件下生存，尽管不是蓬勃发展。此外，我们还表明，在一个经常变化的环境中，一个种群面临的威胁的相似性会影响它能够实现的适应水平。我们用模拟来检验和补充我们的分析结果。
The environment changes constantly at various time scales and, in order to survive, species need to keep adapting. Whether these species succeed in avoiding extinction is a major evolutionary question. Using a multilocus evolutionary model of a mutation-limited population adapting under strong selection, we investigate the effects of the frequency of environmental fluctuations on adaptation. Our results rely on an "adaptive-walk" approximation and use mathematical methods from evolutionary computation theory to investigate the interplay between fluctuation frequency, the similarity of environments, and the number of loci contributing to adaptation. First, we assume a linear additive fitness function, but later generalize our results to include several types of epistasis. We show that frequent environmental changes prevent populations from reaching a fitness peak, but they may also prevent the large fitness loss that occurs after a single environmental change. Thus, the population can survive, although not thrive, in a wide range of conditions. Furthermore, we show that in a frequently changing environment, the similarity of threats that a population faces affects the level of adaptation that it is able to achieve. We check and supplement our analytical results with simulations.