Using Whiptail Lizards to Understand the Integration of Environmental and Host Genetic Effects on Host-Associated Microbiota

动物，包括人类，在他们的身体上和体内藏有大量不同的微生物--所谓的宿主相关微生物群。最近，科学家们开始意识到与宿主相关的微生物区系是宿主健康的重要决定因素。例如，动物肠道中的微生物有助于消化，甚至可以帮助确定动物是瘦的还是肥胖的。与此同时，动物皮肤上的微生物可以影响从伤口愈合到皮肤病易感性的方方面面。尽管与宿主相关的微生物区系对宿主健康很重要，但一个宿主上的微生物区系相对于另一个宿主的微生物区系存在惊人的差异。这些差异是如何出现的？更具体地说，这些差异是先天(即宿主遗传)还是后天(即宿主环境)的结果？由于大多数动物在基因上是独一无二的，很难确定与宿主相关的微生物区系的个体间差异是宿主遗传、环境还是两者共同作用的结果。在鞭尾蜥蜴中，有整个种群的基因完全相同的克隆。更重要的是，这些克隆与其他有性繁殖的鞭尾蜥蜴物种密切相关，在这些物种中，每一种蜥蜴的基因都是独一无二的。通过比较克隆蜥蜴种群和有性繁殖蜥蜴种群中不同环境中寄主相关微生物区系的个体间差异，可以评估寄主遗传和环境对寄主相关微生物区系的相对重要性。这项研究还为本科生提供了一个在研究和科学交流方面进行培训的机会，以帮助培训STEM的下一代劳动力。该项目的战略是使用16S rRNA基因测序来表征和比较四个杂交孤雌生殖螺属物种及其两性亲本的细菌和古细菌肠道和皮肤微生物区系的种内变异。每个蜥蜴复合体(单性原+两性亲本(S))的微生物区系将在单一植被群落(低环境变异)内进行研究，跨不同植被群落(中等环境变异)进行研究，对于系统的子集，将跨广泛的地理范围(高环境变异)进行研究。第一个假设是，与双性恋父母相比，单性生殖基因的变异会更小。第二个假设是，蜥蜴微生物群的个体间差异是由环境驱动的，环境异质性程度越低，微生物群的差异就越小。确定宿主相关微生物区系个体间差异的根本原因将确定管理宿主相关微生物群落组装的规则，进而管理宿主健康、健康和生态成功。这项工作的结果将对理解微生物群落组装和指导宿主保护具有重要意义。例如，了解促进健康宿主微生物群落的因素将有助于澄清在保护区选择期间保护景观多样性与宿主遗传多样性之间的权衡。得到这项建议支持的本科生将有机会进行研究，并开发关于生物研究的播客，以扩大参与范围，并为学生在科学领域的职业生涯进行培训。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。

Animals, including humans, harbor large numbers of different microbes on and in their bodies – so called host-associated microbiota. Recently, scientists have begun to realize that host-associated microbiota are important determinants of host health. Microbes in an animal’s gut, for instance, help digestion and can even help determine whether the animal is lean or obese. Meanwhile, microbes on an animal’s skin can influence everything from wound healing to susceptibility to cutaneous disease. Despite the importance of host-associated microbiota to host health, there is a surprising amount of variation in the microbiota on one host relative to another. How do these differences emerge? More specifically, are these differences a result of nature (i.e., host genetics) or nurture (i.e., host environment)? Because most animals are genetically unique, it can be hard to determine whether inter-individual differences in host-associated microbiota are a result of host genetics, environment or both. In whiptail lizards, there are entire populations of genetically identical clones. What’s more, these clones are closely related to other, sexually reproducing whiptail lizard species where each individual lizard is genetically unique. By comparing inter-individual variation in host-associated microbiota across different environments in clonal lizard populations versus sexually reproducing lizard populations, it will be possible to assess the relative importance of both host genetics and environment on host-associated microbiota. This research also provides an opportunity to train undergraduate students in research and scientific communication to help train the next generation workforce in STEM.The strategy for this project is to use 16S rRNA gene sequencing to characterize and compare intraspecific variation in the bacterial and archaeal gut and skin microbiota of four hybrid parthenogenetic Aspidoscelis species and their bisexual parents. Microbiota of each lizard complex (parthenogen + bisexual parent(s)), will be examined within a single vegetation community (low environmental variation), across different vegetation communities (intermediate environmental variation) and, for a subset of systems, across broad geographic ranges (high environmental variation). The first hypothesis is that variation will be smaller in parthenogens as compared to their bisexual parents. The second hypothesis is that inter-individual variation in lizard microbiota is driven by the environment, and that microbiome variation will be smaller at lower levels of environmental heterogeneity. Determining the underlying causes of inter-individual variation in host-associated microbiota will identify rules governing host-associated microbial community assembly and, by extension, host health, fitness and ecological success. Results from this work will have implications for both understanding microbial community assembly and guiding host conservation. As an example, knowledge of the factors that promote healthy host microbiomes will help to clarify trade-offs between preserving landscape diversity versus host genetic diversity during reserve selection. Undergraduate students who are supported by this proposal will have the chance to perform research and to also develop podcasts about biology research to broaden participation and to train students for careers in the sciences.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.