DISSERTATION RESEARCH: Immunogenetics of Chytridiomycosis Resistance and Susceptibility in Rana yavapaiensis, a Declining North American Anuran

壶菌病是一种新出现的传染病，已引起世界范围内许多两栖动物物种的减少或灭绝。青蛙免疫的遗传学将是了解这种疾病对两栖动物生物多样性的动态和潜在结果的关键。本研究调查了引起壶菌病的病原体水蛭壶菌（Batrachochytrium dendroatidis, Bd）在低地豹蛙（Rana yavapaiensis）中感染的遗传后果。研究人员建议在具有不同历史的青蛙种群中描述疾病流行情况，以确定感染与疾病之间的关系，并在自然种群和实验室饲养的个体中测试壶菌病易感性与青蛙遗传背景之间的关联。青蛙和Bd样本将从遗传上不同的亚利桑那州青蛙种群中收集5年，蝌蚪将在实验室的5个重点地区饲养，用于实验感染。利用每只青蛙的感染和疾病状态以及中性（微卫星）遗传标记和免疫遗传学（主要组织相容性复合体）基因的基因型，本研究将检验有关免疫遗传学、疾病易感性和疾病动力学的假设。了解Bd感染与青蛙死亡率之间的关系，免疫遗传变异对种群疾病动态的重要性，以及宿主基因型对疾病结局的影响，将为今后两栖壶菌病和其他新兴野生动物疾病的研究提供关键的遗传指标。一名研究生和几名本科生将通过参与本项目获得广泛的培训。

The emerging infectious disease chytridiomycosis has caused the decline or extinction of many amphibian species worldwide. The genetics of frog immunity will be critical to understanding the dynamics and potential outcome of this disease for amphibian biodiversity. This study investigates the genetic consequences of infection by the chytridiomycosis-causing pathogen Batrachochytrium dendrobatidis (Bd) in the lowland leopard frog, Rana yavapaiensis. The researchers propose to characterize disease prevalence across frog populations with different histories to determine the relationship between infection and disease, and to test for associations between chytridiomycosis susceptibility and frog genetic background in natural populations and in lab-reared individuals. Frog and Bd samples will be collected from genetically-distinct Arizona frog populations for five years, and tadpoles will be reared from five focal localities for experimental infections in the laboratory. Using each frog's infection and disease status along with genotypes at neutral (microsatellite) genetic markers and immunogenetic (major histocompatibility complex) genes, this study will test hypotheses about immunogenetics, disease susceptibility, and disease dynamics.Understanding the relationship between Bd infection and frog mortality, the importance of standing immunogenetic variation for population disease dynamics, and the effect of host genotype on disease outcome, will provide critical genetic indices for future studies of amphibian chytridiomycosis and other emerging wildlife diseases. One graduate student and several undergraduate students will receive broad training through participation in this project.