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

越来越多的人认识到，进化在传染病的出现和重新出现中发挥着核心作用。然而，我们对为什么一些病原体和寄生虫能迅速适应新的环境，而另一些却不能，这一理解仍然不完整。一些寄生虫快速进化的这种能力(即可进化性)使它们能够“跳”感染新的寄主物种。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进化的条件。了解进化能力产生差异的原因可以帮助识别潜在的新出现的疾病，并为降低其传播能力的管理策略提供信息。直觉上讲，更大的进化性对寄生虫是有益的，但进化性不会直接增加寄生虫的繁殖力或存活率。因此，它是如何在人群中产生或维持的还不太清楚。计算机模拟的结果表明，在不可预测和不断变化的环境中，进化性是有利的。该项目使用宿主-寄生虫共同进化的计算机模拟，以及使用自然细菌-啮齿动物系统的野外和实验室实验，以确定寄生虫生态中促进或阻碍进化性进化的特定方面。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，为本科生和中学课堂提供材料，以及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，在那里，多个宿主物种具有重叠的范围，并且在单个宿主内发生多种感染。该项目将致力于四个中心目标：1)量化寄主异质性对寄生虫进化性和多样性的影响；2)测量寄主异质性如何影响多种寄生虫物种共感染的流行率和强度；3)确定寄生生物共感染对进化性和多样性的影响；以及4)量化寄主异质性和寄生虫共感染对进化性和多样性的综合影响。使用Avida的实验，一个数字宿主和寄生虫以开放方式进化的计算平台，将得到现场采样和使用以色列内盖夫沙丘的Bartonella寄生虫及其野生啮齿动物宿主的实验室进化实验的结合。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.