Collaborative Research: EAGER: Developing tools to assess the evolutionary implications of partial clonality in alpine snow algae

许多全球重要的过程，如碳循环和人类疾病动力学，都是微观真核生物的结果。然而，由于研究微观类群的内在挑战，我们对整个生命树的进化过程的理解是有限的。为宏观的、通常是强制性的有性繁殖而开发的工具在微生物中往往难以处理，因为微生物的世代时间短，种群规模大，很难从单个细胞中提取DNA。此外，种群水平的生态学和进化生物学研究侧重于可以在实验室中生长的物种；然而，只有1%的微生物可以培养。这项提案的重点是雪藻，这是一组密切相关的单细胞藻类，它们会将季节性的雪包变成粉红色或红色。其目的是开发新的单细胞种群遗传方案来研究这些受威胁的生物和环境变化的哨兵。来自美国喀斯喀特山脉年间和年内以木瓜单胞菌为主的水华的数千个细胞将进行基因分型。一个目标是了解环境因素(如氮)如何影响雪藻的繁殖。该项目将支持两名研究生。这三个PI将把数据整合到大学水平的课堂和实地课程中，并通过社交媒体和同行评议的出版物与公众共享数据。这个项目使用雪藻来开发研究自然种群中微生物真核生物种群遗传学的新方法。这项工作将为研究繁殖模式提供新的关键技术，这些模式将广泛适用于微生物系统。提出了两个新的元素：(1)将单细胞分离方法与最先进的多位点基因分型相结合，(2)使用一种新的微生物真核系统(雪藻)，其特点使该方法的开发易于处理。将生成繁殖模式数据，并将其与(I)细胞倍性和(Ii)环境条件的测量相结合，以确定有限的氮是否启动有性繁殖。与依赖实验室培养的传统微藻种群遗传学相比，这种方法截然不同，这引发了这些数据在自然界中的代表性有多大的问题。这项建议适合急切的资助机制，因为单细胞群体基因方法是高风险、高回报的，应该可以很容易地转移到其他系统。这一奖项反映了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。

Many globally important processes like carbon cycling and human disease dynamics are a result of microscopic eukaryotes. Yet our understanding of evolutionary processes across the entire tree of life is limited due to the inherent challenges of studying microscopic taxa. Tools developed for macroscopic, and often obligately sexually reproducing, species are often not tractable in microbes where generation times are short, population sizes large, and extracting DNA from individual cells difficult. Further, population-level ecology and evolutionary biology research have focused on species that can be grown in the lab; yet, only ~1% of microbes can be cultured. This proposal focuses on the snow algae, a group of closely related, single-celled algae that turn seasonal snow packs pink or red. The aim is to develop novel single-cell population genetic protocols to study these threatened organisms and sentinels of environmental change. Thousands of cells from inter- and intra-annual Chlainomonas-dominated blooms in the Cascade Range of the United States will be genotyped. A goal is to understand how environmental factors (e.g., nitrogen) influence snow algal reproduction. The project will support two graduate students. The three PIs will integrate data into classroom-based and field-based curriculum for university-level students and share data with the public through social media and peer-reviewed publications.This project uses snow algae to develop new methods for studying the population genetics of microbial eukaryotes from natural populations. The work will provide novel and critical techniques for studying reproductive modes that will be broadly applicable across microbial systems. Two novel elements are proposed: (1) combining single-cell isolation methods with state-of-the-art multilocus genotyping, and (2) using a novel microbial eukaryotic system (snow algae) with features making the method development tractable. Reproductive mode data will be generated and combined with measurements of (i) the ploidy of cells and (ii) environmental conditions to ascertain whether limited nitrogen initiates sexual reproduction. The approach is radically different compared to traditional microalgal population genetics that rely on lab-based cultures, raising questions of how representative those data are in nature. This proposal fits the EAGER funding mechanism as the single-cell population genetic methods are high risk-high payoff and should be readily transferable to other systems.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.