Antagonistic coevolution has long been suggested to help maintain host genetic variation. While, ecological and epidemiological feedbacks are known to have important consequences on coevolutionary allele frequency dynamics, their effects on the maintenance of genetic variation remains poorly understood. Here, we extend previous work on the maintenance of genetic variation in a classic matching-alleles coevolutionary model by exploring the effects of ecological and epidemiological feedbacks, where both allele frequencies and population sizes are allowed to vary over time. We find that coevolution rarely maintains more host genetic variation than expected under neutral genetic drift alone. When and if coevolution maintains or depletes genetic variation relative to neutral drift is determined, predominantly, by two factors: the deterministic stability of the Red Queen allele frequency cycles and the chance of allele fixation in the pathogen, as this results in directional selection and depletion of genetic variation in the host. Compared to purely coevolutionary models with constant host and pathogen population sizes, ecological and epidemiological feedbacks stabilize Red Queen cycles deterministically, but population fluctuations in the pathogen increase the rate of allele fixation in the pathogen, especially in epidemiological models. Our results illustrate the importance of considering the ecological and epidemiological context in which coevolution occurs when examining the impact of Red Queen cycles on genetic variation. This article is protected by copyright. All rights reserved.

中文翻译：

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共同进化和流行病学之间的反馈可以帮助或阻碍宿主寄生虫模型中遗传变异的维持

长期以来，人们一直建议拮抗共同进化有助于维持宿主遗传变异。虽然已知生态和流行病学反馈对共同进化等位基因频率动态具有重要影响，但它们对维持遗传变异的影响仍知之甚少。在这里，我们通过探索生态和流行病学反馈的影响，扩展了以前在经典匹配等位基因协同进化模型中维持遗传变异的工作，其中等位基因频率和种群规模都可以随时间变化。我们发现，在单独的中性遗传漂变下，共同进化很少保持比预期更多的宿主遗传变异。何时以及是否共同进化维持或消除相对于中性漂移的遗传变异，主要由两个因素决定：红皇后等位基因频率循环的确定性稳定性和病原体中等位基因固定的机会，因为这会导致定向选择和宿主遗传变异的消耗。与具有恒定宿主和病原体种群大小的纯共同进化模型相比，生态和流行病学反馈确定性地稳定了红皇后循环，但病原体的种群波动会增加病原体中等位基因固定的速率，尤其是在流行病学模型中。我们的结果说明了在检查红皇后周期对遗传变异的影响时考虑共同进化发生的生态和流行病学背景的重要性。本文受版权保护。版权所有。