Data from: Linking genetic and environmental factors in amphibian disease risk

A central question in evolutionary biology is how interactions between organisms and the environment shape genetic differentiation. The pathogen Batrachochytrium dendrobatidis (Bd) has caused variable population declines in the lowland leopard frog (Lithobates yavapaiensis); thus, disease has potentially shaped, or been shaped by, host genetic diversity. Environmental factors can also influence both amphibian immunity and Bd virulence, confounding our ability to assess the genetic effects on disease dynamics. Here, we used genetics, pathogen dynamics, and environmental data to characterize L. yavapaiensis populations, estimate migration, and determine relative contributions of genetic and environmental factors in predicting Bd dynamics. We found that the two uninfected populations belonged to a single genetic deme, whereas each infected population was genetically unique. We detected an outlier locus that deviated from neutral expectations and was significantly correlated with mortality within populations. Across populations, only environmental variables predicted infection intensity, whereas environment and genetics predicted infection prevalence, and genetic diversity alone predicted mortality. At one locality with geothermally elevated water temperatures, migration estimates revealed source–sink dynamics that have likely prevented local adaptation. We conclude that integrating genetic and environmental variation among populations provides a better understanding of Bd spatial epidemiology, generating more effective conservation management strategies for mitigating amphibian declines.进化生物学的核心议题之一，是生物与环境的相互作用如何塑造遗传分化。病原真菌蛙壶菌（Batrachochytrium dendrobatidis, Bd）已导致低地豹蛙（Lithobates yavapaiensis）出现不等程度的种群衰退，因此疾病既可能塑造宿主的遗传多样性，也可能受宿主遗传多样性的调控。环境因素可同时影响两栖动物的免疫力与蛙壶菌的毒力，这给我们评估疾病动态中的遗传效应带来了混杂干扰。本研究整合遗传学数据、病原动态数据与环境数据，对低地豹蛙种群进行表征，估算种群迁移率，并明确遗传与环境因素在预测蛙壶菌动态中的相对贡献。研究结果显示，两个未受感染的种群同属一个遗传同类群（deme），而每个受感染种群均具有独特的遗传特征。我们检测到一个偏离中性理论预期的离群位点，该位点与种群内的死亡率呈显著相关。跨种群分析表明，仅环境变量能够预测感染强度；感染流行率可由环境与遗传因素共同预测，而死亡率仅能通过遗传多样性单独预判。在一处水温因地热作用升高的采样点，迁移率估算结果揭示了源-汇动态，这一动态或已阻碍了当地的本地适应过程。本研究结论指出，整合种群间的遗传与环境变异，能够深化我们对蛙壶菌空间流行病学的认知，为缓解两栖动物种群衰退制定更为高效的保护管理策略提供支撑。