Dissertation Research: Genetic and Environmental Mechanisms Mediating Disease Resistance and Tolerance in Amphibians

确定野外传染病反复爆发的原因对于了解人类和生态系统健康至关重要。环境变化可能会降低宿主进化抗性或在其耐受限度内持续存在的能力，从而使病原体更有可能引起疾病和死亡。该项目调查热带两栖动物感染的季节性变化模式，并测试疾病模式是对病原体具有遗传抗性的个体频率变化的结果，或者是环境压力导致的宿主条件减弱的结果。缺乏遗传决定因素的青蛙也可能依赖于环境调节剂（例如，共生细菌）以减轻病原体损害。这些免疫策略如何以及何时相互作用，使两栖动物持续出现疾病尚不清楚。使用下降的青蛙种群在波多黎各，表现出高度异质性和季节性的感染动态，PI结合联合收割机人口基因组学和宏基因组学，以确定环境和宿主适应性反应如何影响疾病的结果。两栖动物减少的话题及其对环境健康的影响已经引起了公众的注意;因此，这个项目提供了一个很好的机会来教育非科学家关于遗传学，免疫力和疾病生态学。这两个研究所都通过媒体、教育宣传和非政府组织向广大受众传播其科学研究成果。此外，该项目涉及来自代表性不足的少数民族的学生和研究人员，促进美国和波多黎各机构之间的合作，并增加对生态学，进化和保护感兴趣的学生的多样性。这些结果可供保护机构在物种优先级计划和圈养繁殖计划中使用。

Identifying the causes of recurrent outbreaks of infectious diseases in the wild is critical to understanding human and ecosystem health. Environmental change may reduce the ability of hosts to evolve resistance or persist within their tolerance limits, thus making pathogens more likely to cause disease and mortality. This project investigates seasonally variable patterns of infection in tropical amphibians and tests the hypotheses that disease patterns are a consequence of changes in the frequency of individuals that have genetically-based resistance to the pathogen, or alternatively, a result of a weakened host condition caused by environmental stress. Frogs lacking genetic determinants may also rely on environmental modulators (e.g., symbiotic bacteria) to alleviate pathogen damage. How and when these immune strategies interact to allow amphibians to persist emergent diseases is unknown. Using declining frog populations in Puerto Rico that exhibit high heterogeneity and seasonality in infection dynamics, the PIs combine population genomics and metagenomics to determine how environmental and host adaptive responses affect the outcome of disease. The topic of amphibian declines, and its implications for environmental health, has reached public awareness; thus this project offers an excellent opportunity to educate non-scientists about genetics, immunity, and disease ecology. Both PIs disseminate their scientific findings to general audiences through media, educational outreach, and NGOs. In addition, the project involves students and researchers from underrepresented minorities, fosters collaborations between USA and Puerto Rican institutions, and increases diversity among students interested in ecology, evolution, and conservation. These results can be used by conservation agencies in species prioritization schemes and captive breeding programs.