Genetic diversity predicts susceptibility to a deadly emerging disease

New infectious diseases threaten humans, livestock and the conservation of endangered wildlife. Like nearly a third of all amphibians, the Italian agile frog is a declining species facing potential extinction. In north western Italy its populations are severely depleted in genetic variation, while eastern populations remain genetically variable.

Theory and molecular immunology predict that reduced genetic diversity increases susceptibility to new diseases. Does reduced genetic diversity over a large portion of a species' range imply similarly widespread disease risk? In the April issue of Ecology Letters, Pearman and Garner report an experimental test of this prediction. They exposed tadpoles of the Italian agile frog to a virus isolated in North America, thereby simulating the pathogen's outbreak in Europe.

The disease susceptibility of tadpoles paralleled the genetic variability in their populations of origin. This result highlights the potential dangers of population bottlenecks and inbreeding, while suggesting a means to predict responses to new infectious diseases.

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