RUI: Development and application of genomic resources for ascidian taxonomy and holobiont evolution

海鞘，非正式地称为海鞘，是海洋无脊椎动物中的一个重要群体。例如，它们是我们最接近的无脊椎动物亲戚，因此经常被用作研究脊椎动物发育和进化的模型。此外，某些海鞘动物非常有效地入侵新的沿海栖息地，在那里它们茁壮成长，改变自然群落，给水产养殖业造成相当大的经济损失。识别野生海鞘物种很重要，但也可能是具有挑战性的，因为它们只在外表上有细微的差异，而且在通常用于识别海洋物种的DNA片段上也有细微的差异。因此，找到一组新的DNA区域，使研究人员能够更准确地识别海鞘物种，并解决入侵物种传播中的重要问题，将是这项研究的一个关键方面。这项研究还将重点放在海鞘肠道的微生物上。这些似乎在允许某些物种在入侵新地区时取得成功方面发挥了关键作用。这项研究将更好地描述海鞘肠道微生物的特征，揭示这些微生物是否与它们所在的宿主进化一致，并帮助揭示微生物在允许在新的栖息地成功建立海鞘方面所起的作用。该项目将为三所大学的至少九名本科生提供实践研究经验，并将培训24名学生学习海鞘分类学，包括在STEM中代表性不足的学生。将为自然资源管理人员和其他科学家举办关于相对原始和变化的海洋生境中海鞘多样性的讲习班。该项目将在海鞘生命树上开发新的核基因组标记，这将增加对该群体进行系统发育和系统研究的机会。此外，对这些新标记的分析以及形态研究将用于调查和清点伯利兹港口和礁石栖息地的海鞘动物，伯利兹是该小组的生物多样性热点；关于分类鉴定和分布的信息将作为目录免费提供。这份清单将扩展和更新我们关于海鞘生物多样性和沿中美洲堡礁系统的分布的知识，该系统是一个关键的、受到威胁的生态系统。它还将记录引进的海鞘物种的流行情况，并根据综合分子和形态数据为40多个以前从未测序的物种提供鉴定。此外，这个项目将描述海鞘肠道的微生物群。这种微生物群在允许某些海鞘生物成功入侵新的栖息地方面发挥了关键作用，并可能在海鞘进化中发挥了重要作用。结构(分类类群)和功能(特定基因)特征的变化将被绘制在海鞘生命树上，以更深入地了解微生物共生体在海鞘进化中的作用。通过将形态学与新开发的分子标记相结合，将这种综合方法应用于引进物种鉴定，并将微生物共生作为海鞘进化的驱动力进行调查，该项目将显著促进我们对海鞘多样性和系统发育以及促进生物入侵的因素的理解。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。

The ascidians, informally known as sea squirts, are an important group of marine invertebrates. For instance, they are our closest invertebrate relatives, and are thus often used as models to study vertebrate development and evolution. Further, certain ascidians are very effective at invading new coastal habitats where they thrive, altering natural communities and causing considerable economic loss to the aquaculture industry. Identifying ascidian species in the wild is important but can be challenging, as they differ only subtly in their appearance and also in the short stretches of DNA typically used to identify marine species. Thus, finding a new set of DNA regions that will allow researchers to more accurately identify ascidian species and address important questions in invasive species spread will be a key aspect of this research. The research will also focus on the microbes of the sea squirt gut. These appear to play a key role in allowing certain species to succeed when they invade new regions. This research will better characterize ascidian gut microbes, shed light on whether these microbes evolve in concert with the hosts they occur in, and help shed light on the role microbes play in allowing the successful establishment of sea squirts in new habitats. This project will provide hands-on research experience for at least nine undergraduate students at three universities and will train 24 students in ascidian taxonomy, including students underrepresented in STEM. A workshop on ascidian diversity in both relatively pristine and altered marine habitats will be offered to natural resource managers and other scientists. This project will develop new nuclear genome markers across the ascidian tree of life, which will enhance opportunities to conduct phylogenetic and systematic research on the group. Further, analysis of these novel markers, along with morphological studies, will be used to survey and inventory ascidians from both harbor and reef habitats in Belize, a biodiversity hot spot for the group; information on taxonomic identification and distribution which will be made freely available as a catalog. This inventory will extend and update our knowledge of ascidian biodiversity and distribution along the Mesoamerican Barrier Reef System, a key, threatened ecosystem. It will also document the prevalence of introduced ascidian species and provide identifications based on integrated molecular and morphological data for over 40 species never previously sequenced. Furthermore, this project will characterize the microbiome of the ascidian gut. This microbiome plays a key role in allowing certain ascidians to successfully invade new habitats and may have been important in ascidian evolution. The variation in structural (taxonomic groups) and functional (specific gene) features will be mapped out across the ascidian tree of life to provide more insight into the role of microbial symbionts in ascidian evolution. By combining morphology with newly developed molecular markers, applying this integrative approach to introduced species identification, and investigating microbial symbiosis as a driver of ascidian evolution, this project will significantly advance our understanding of ascidian diversity and phylogenetics and the factors promoting biological invasions.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.