Population Structure of Schistosomes and Host Snails

描述(由申请人提供)：血吸虫与其蜗牛宿主之间的相互作用在宿主和寄生虫遗传系统的进化发展中发挥着重要作用。基因流、遗传漂移和选择都可能作用于这些系统，推动共同进化轨迹并决定疾病动态。评估宿主和寄生虫的遗传异质性的程度和结构是预测传染病流行病学的重要第一步。最近对曼氏血吸虫和光滑生物等位基因微卫星标记的表征为我们在局部空间尺度上研究寄生虫和宿主的种群结构提供了机会。该项目的具体目标包括： 1)根据来自微卫星的等位基因数据确定血吸虫和蜗牛种群细分的相对性质，并评估这种遗传变异在空间和时间尺度上的变化；以及 2)将微卫星等位基因异质性与血吸虫毒力和钉螺抗性的生物标志物相关联，以评估遗传变异与具有流行病学重要性的表型表达之间的关系。了解宿主和寄生虫遗传多样性在个体宿主内和宿主之间的分布，以及在种群内和种群之间的分布，将使我们能够估计寄生虫的基因流动，评估多种寄生虫基因类型对血吸虫毒力的重要性，并开始了解驱动疾病动态的微观进化力量之间的相互作用。结果将产生对流行病学过程的进化洞察，有助于确定控制策略的遗传后果，并补充对巴西流行社区人类的同时免疫流行病学研究。

DESCRIPTION (provided by the applicant): Interactions between schistosomes and their snail hosts play an important role in the evolutionary development of host and parasite genetic systems. Gene flow, genetic drift and selection all potentially act on these systems, driving co-evolutionary trajectories and dictating disease dynamics. Assessing the degree and structure of genetic heterogeneity of both hosts and parasites is an essential first step in predicting the epidemiology of infectious diseases. The recent characterization of allelic microsatellite markers for Schistosoma mansoni and Biomphalaria glabrata provides us with an opportunity to study population structure of both parasite and host on a local spatial scale. Specific aims of this project include: 1) Determining the relative nature of population subdivision for schistosomes and snails based on allelic data from microsatellites, and assessing how that genetic variation changes on both spatial and temporal scales; and 2) Correlating microsatellite allelic heterogeneity with biomarkers for schistosome virulence and snail resistance to assess relationships between genetic variation and phenotypic expressions of epidemiological importance. Knowledge of the distribution of host and parasite genetic diversity within and among individual hosts, and within and among populations, will allow us to estimate parasite gene flow, assess the importance of multiple parasite genotypes on schistosome virulence, and begin to understand the interplay among micro-evolutionary forces that drive disease dynamics. Results will yield evolutionary insights into the epidemiological process, help to identify genetic consequences of control strategies, and complement concurrent immuno-epidemiology studies of humans in endemic Brazilian communities.