Does Genetic Diversity Reduce the Risk of Infection?
What do bananas, potatoes, and Tasmanian devils have in common? They are all alleged victims of the "monoculture effect". According to this idea, parasites spread readily between closely-related individuals, resulting in large outbreaks of infectious disease in genetically homogenous groups of hosts. The idea presents an obvious solution: increasing genetic variation between individuals within a group should impede parasite transmission, lowering the risk of infection. The link between diversity and disease has become conventional wisdom. We even have "software monocultures", which purportedly enabled the 2017 WannaCry ransomware attack. Yet we lack a sense of how general the monoculture effect is (reviewed in King and Lively 2012, Heredity). Does genetic diversity reduce the risk of infection in natural populations? Or do we see this phenomenon only in artificial environments, like agricultural fields, where host diversity is very low and host density is very high? I will conduct a meta-analysis of existing studies of the relationship between genetic diversity and disease. My approach will provide an estimate of the average direction and magnitude of the impact of genetic diversity on disease spread. I will also compare the size of the effect in agricultural vs. natural settings and in controlled vs. field tests. This work will evaluate the significance of genetic diversity for the health of natural populations and characterize the dynamics of infectious diseases in heterogeneous host populations.
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