Data from: Reciprocal interaction matrix reveals complex genetic and dose-dependent specificity among coinfecting parasites

Understanding genetic specificity in factors determining the outcome of host-parasite interactions is especially important as it contributes to parasite epidemiology, virulence, and maintenance of genetic variation. Such specificity, however, is still generally poorly understood. We examined genetic specificity in interactions among coinfecting parasites. In natural populations, individual hosts are often simultaneously infected by multiple parasite species and genotypes that interact. Such interactions could maintain genetic variation in parasite populations if they are genetically specific so that the relative fitness of parasite genotypes varies across host individuals depending on (1) the presence/absence of coinfections and/or (2) the genetic composition of the coinfecting parasite community. We tested these predictions using clones of fish eye flukes Diplostomum pseudospathaceum and Diplostomum gasterostei. We found that interactions among parasites had a strong genetic basis and that this modified genetic variation in infection success of D. pseudospathaceum between single and multiple infections as well as across multiply infected host individuals depending on the genetic identity of the coinfecting D. gasterostei. The relative magnitude of these effects, however, depended on the exposure dose, suggesting that ecological factors can modify genetic interactions between parasites.

解析宿主-寄生虫互作（host-parasite interactions）结局决定因子中的遗传特异性（genetic specificity）具有重要研究价值，因其与寄生虫流行病学、毒力及遗传变异的维持密切相关。但目前学界对这类遗传特异性的认知仍普遍不足。我们针对共感染寄生虫间的遗传特异性展开了研究。在自然种群中，单个宿主通常会同时被多种寄生虫物种与基因型感染并发生互作。若这类互作具有遗传特异性，即寄生虫基因型的相对适合度（relative fitness）会随宿主个体不同而产生差异，且差异取决于（1）是否存在共感染，以及（2）共感染寄生虫群落的遗传组成，那么此类互作或可维持寄生虫种群的遗传变异。我们以鱼类眼吸虫伪双穴吸虫（Diplostomum pseudospathaceum）及刺鳅双穴吸虫（Diplostomum gasterostei）的克隆株为材料，对上述预测进行了验证。研究发现，寄生虫间的互作具有显著的遗传基础，且该基础改变了伪双穴吸虫在单感染与多感染情境下的感染成功率遗传变异；同时，在多重感染的宿主个体间，伪双穴吸虫的感染成功率变异也会因共感染的刺鳅双穴吸虫的遗传身份不同而产生差异。但上述效应的相对强度取决于暴露剂量（exposure dose），这表明生态因子可调控寄生虫间的遗传互作。