Does genetic diversity protect host populations from parasites? A meta-analysis across natural and agricultural systems

If parasites transmit more readily between closely related hosts, then parasite burdens should decrease with increased genetic diversity of host populations. This important hypothesis is often accepted at face value - notorious epidemics of crop monocultures testify to the vulnerability of host populations that have been purged of diversity. Yet the relationship between genetic diversity and parasitism likely varies across contexts, differing between crop and non-crop hosts and between experimental and natural host populations. Here, we used a meta-analytic approach to ask if host diversity confers protection against parasites over the range of contexts in which it has been tested.

We synthesized the results of 102 studies, comprising 2,004 effect sizes representing a diversity of approaches and host-parasite systems. Our results validate a protective effect of genetic diversity, while revealing significant variation in its strength across biological and empirical contexts. In experi...

若寄生虫在亲缘关系较近的宿主间更易传播，则宿主种群的寄生虫负荷（parasite burdens）应随宿主种群遗传多样性的提升而降低。这一重要假说常被不加批判地直接采信——臭名昭著的作物单一种植流行病，恰恰佐证了遗传多样性被清除的宿主种群的脆弱性。然而，遗传多样性与寄生现象之间的关联很可能因研究情境而异，在作物宿主与非作物宿主之间、实验宿主种群与自然宿主种群之间均存在显著差异。本研究采用元分析（meta-analysis）方法，旨在探究在已开展相关测试的各类研究情境中，宿主遗传多样性是否能够为宿主提供抗寄生虫感染的保护作用。
本研究整合了102项研究的结果，涵盖2004个效应量（effect sizes），涉及多样化的研究方法与宿主-寄生虫系统（host-parasite systems）。研究结果证实了遗传多样性的保护作用，同时揭示了其保护效力在不同生物学与实证研究情境中存在显著差异。在实验...