When does parasitism maintain sex in the absence of Red Queen Dynamics?
When does parasitism maintain sex in the absence of Red Queen Dynamics?
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DOI：
10.1111/jeb.13718
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发表时间：
2020-11-18
影响因子：
2.1
通讯作者：
Ashby, Ben
中科院分区：
文献类型：
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作者：
Ashby, Ben
寄生虫可以选择在宿主种群中进行有性生殖，防止被生长更快的无性基因型取代。这通常归因于所谓的“红皇后动力学”（RQD），其中拮抗性协同进化导致等位基因频率的波动选择，这为性别提供了优于asex的优势。然而，寄生也可以保持性别的情况下，RQD时，性种群的遗传多样性，因此更耐，平均比克隆种群，使性别和无性系共存于一个稳定的平衡。虽然由于RQD的性的维持已被广泛研究，允许性和asex稳定共存的条件还有待详细探讨。特别是，我们缺乏对宿主人口统计学和寄生虫流行病学如何在没有RQD的情况下影响性维持的理解。在这里，我用一个生态进化模型来表明，人口密度和类型和强度的毒力是重要的维持性别，这可以理解的疾病的流行和严重程度的影响。此外，我表明，即使在没有杂合子优势，无性杂合性影响共存与性别由于生态位重叠的变化。这些结果揭示了在没有RQD的情况下，宿主和寄生虫的特征对维持性别是最重要的，并提供了人口统计学和流行病学如何介导性别和无性生殖之间的竞争的经验可检验的预测。
Parasites can select for sexual reproduction in host populations, preventing replacement by faster-growing asexual genotypes. This is usually attributed to so-called 'Red Queen dynamics' (RQD), where antagonistic coevolution causes fluctuating selection in allele frequencies, which provides sex with an advantage over asex. However, parasitism may also maintain sex in the absence of RQD when sexual populations are more genetically diverse-and hence more resistant, on average-than clonal populations, allowing sex and asex to coexist at a stable equilibrium. Although the maintenance of sex due to RQD has been studied extensively, the conditions that allow sex and asex to stably coexist have yet to be explored in detail. In particular, we lack an understanding of how host demography and parasite epidemiology affect the maintenance of sex in the absence of RQD. Here, I use an eco-evolutionary model to show that both population density and the type and strength of virulence are important for maintaining sex, which can be understood in terms of their effects on disease prevalence and severity. In addition, I show that even in the absence of heterozygote advantage, asexual heterozygosity affects coexistence with sex due to variation in niche overlap. These results reveal which host and parasite characteristics are most important for the maintenance of sex in the absence of RQD, and provide empirically testable predictions for how demography and epidemiology mediate competition between sex and asex.