US-Israel Collab: Are parasites in complex communities more evolvable? Bridging ecology and evolution with computational modeling and rodent-bacteria evolution experiments

人们日益认识到，进化在传染病的出现和重新出现中起着核心作用。然而，为什么一些病原体和寄生虫能迅速适应新环境，而另一些却不能，我们的理解仍然不完整。某些寄生虫的这种快速进化能力（即可进化性）使它们能够“跳跃”感染新的宿主物种。这个项目将研究一些相互作用的动物和微生物的自然群落是否以及如何产生有利于可进化性进化的条件。了解为什么会出现可进化性变异，有助于识别潜在的新发疾病，并为降低其传播能力的管理策略提供信息。从直觉上讲，更大的可进化性对寄生虫是有益的，但可进化性并不直接增加寄生虫的繁殖或存活率。因此，目前尚不清楚它是如何在种群中产生或维持的。计算机模拟的结果表明，在不可预测和不断变化的环境中，进化是有利的。该项目使用宿主-寄生虫共同进化的计算机模拟，以及使用天然细菌-啮齿动物系统进行现场和实验室实验，以确定促进或阻碍可进化性进化的寄生虫生态的特定方面。这个项目是与以色列科学家合作的。它将为科学界开发新的计算工具，为本科和中学教室开发材料，并为密歇根州的教师提供教师培训和研究经验。寄生虫种群通常在复杂的群落中进化，其中多个宿主物种具有重叠的范围，并且在单个宿主中发生多次感染。该项目将解决四个中心目标：1)量化宿主异质性对寄生虫进化和多样性的影响；2)测量宿主异质性如何影响多种寄生虫共同感染的患病率和强度；3)确定寄生虫共感染对进化性和多样性的影响；4)量化宿主异质性和寄生虫共感染对进化性和多样性的综合影响。利用Avida（一个数字宿主和寄生虫以开放式方式进化的计算平台）进行的实验，将辅以在以色列内盖夫沙丘使用巴尔通体寄生虫及其野生啮齿动物宿主进行的现场抽样和实验室进化实验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There is a growing appreciation that evolution plays a central role in the emergence and reemergence of infectious diseases. However, our understanding of why some pathogens and parasites rapidly adapt to novel environments, while others don't, remains incomplete. This ability of some parasites to evolve rapidly (i.e., evolvability) allows them to "jump" into infecting new host species. This project will examine whether and how some natural communities of interacting animals and microbes generate conditions that favor the evolution of evolvability. Understanding why variation in evolvability arises can help to identify potential emerging diseases and inform management strategies that reduce their ability to spread. It makes intuitive sense that greater evolvability is beneficial for the parasite, but evolvability does not directly increase the parasite's reproduction or survivorship. Thus, it is less clear how it arises or is maintained in populations. Results from computer simulations suggest that evolvability is advantageous in unpredictable and constantly changing environments. The project uses computer simulations of host-parasite coevolution as well as field and laboratory experiments using a natural bacteria-rodent system to identify specific aspects of parasite ecology that promote or hinder the evolution of evolvability. This project is a collaboration with Israeli scientists. It will develop new computational tools for the scientific community, materials for undergraduate and secondary school classrooms, as well as teacher training and research experience for teachers in Michigan. Parasite populations typically evolve in complex communities, where multiple host species have overlapping ranges, and multiple infections occur within a single host. This project will address four central aims: 1) quantifying the effect of host heterogeneity on parasite evolvability and diversity; 2) measuring how host heterogeneity influences the prevalence and intensity of coinfection by multiple parasite species; 3) identifying the effect of parasite coinfection on evolvability and diversity; and 4) quantifying the combined effects of host heterogeneity and parasite coinfection on evolvability and diversity. Experiments using Avida, a computational platform where digital hosts and parasites evolve in an open-ended fashion, will be complemented by a combination of field-site sampling and laboratory evolution experiments using Bartonella parasites and their wild rodent hosts in the Israeli Negev Dunes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.