Collaborative Research: Life cycle evolution in Rotifera: The influence of sexual reproduction on contemporary systematics of Monogononta

合作研究：轮虫的生命周期进化：有性生殖对当代 Monogononta 系统学的影响

基本信息

批准号：
2051710
负责人：
Robert Wallace
金额：
$ 11.21万
依托单位：
Ripon College
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-15 至 2025-03-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2051710&HistoricalAwards=false
关键词：
Collaborative Research Life cycle evolution

项目摘要

Rotifers are tiny (≤2 mm) invertebrate animals that can be found anywhere there is liquid water. For instance, they inhabit shallow sea water, lakes, ponds, streams, irrigation ditches, ephemeral basins in deserts, meltwater puddles on glaciers, and thin layers of water on soils and plants. Rotifers play vital roles in ecological systems as both predators and prey, and the nutrients they contain are passed up the food chain to insects and fish. Scientists study rotifers to better understand aging, aquaculture, ecology, development, and the evolution of reproductive modes. A fascinating feature of rotifers are their complex life cycles: some alternate generations, whereas others primarily reproduce by creating clones of themselves. This work will use genetic analyses and comparisons of anatomy that rely on advanced microscopic imaging to determine the evolutionary history of a major group of rotifers and examine how life cycles and reproductive mode changed as the group evolved. Many species from diverse habitats will be considered, and the research will also result in better characterization of the life cycles of species that are poorly known. As part of the project, educational workshops and museum displays will be produced, contributions will be made to online databases, and a scientific symposium will be held at a national meeting. Further, a postdoctoral scientist, along with graduate, undergraduate, and high school students, will be trained to conduct studies of this diverse animal group. The goal of this project is to build a comprehensive phylogeny of rotifers with a focus on the Class Monogononta, the most speciose and diverse lineage in the phylum. This research will provide a framework for testing how the diversification of the group is associated with the origins of different reproductive modes. The project has three aims. (1) It will produce a comprehensive phylogeny of rotifers using molecular sequence data and morphology; the morphological studies will utilize conventional electron microscopy, focused ion-beam scanning electron microscopy, atomic force microscopy, and confocal laser scanning microscopy; the morphology of at least 100 species representing nearly 90% of family diversity will be considered. (2) It will use the phylogeny and ancestral state reconstruction methods to investigate questions concerning the evolution of reproductive traits in rotifers. In particular, (a) how did the maternal provisioning of nutrients (i.e., matrotrophy) and internal brooding evolve from egg-laying species? (b) how did the ability to produce both mitotic and meiotic ova in a single animal evolve from cyclical parthenogenesis? (c) do eggshells produced by species with different reproductive modes show similarities in morphology, chemistry, and mechanical properties, and are these correlated with life history traits? And (d) has the small size of certain life cycle stages evolved more than once? (3) The phylogeny will also be used to identify monophyletic groups, present a predictive classification of rotifers, revise or produce new diagnoses for taxa above the genus level, and produce species keys. Additionally, because Rotifera is the most diverse clade (2000 species) and the only gonochoristic group within the larger lineage Gnathifera (~3575 species from five higher taxa: Chaetognatha, Gnathostomulida, Micrognathozoa, Rotifera, Acanthocephala), rotifers are ideal candidates to provide insights into gnathiferan evolution and help answer questions about the evolution of reproductive diversity, jaws (e.g., Gnathifera), and parasitism (e.g., Acanthocephala).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.

轮虫是微小（≤2毫米）的无脊椎动物，可以在任何有液态水的地方找到，例如，它们栖息在浅海水、湖泊、池塘、溪流、灌溉沟渠、沙漠中的短暂盆地、冰川上的融水水坑和薄薄的水坑中。科学家研究，土壤和植物上的水层在生态系统中发挥着至关重要的作用，它们既是捕食者，也是猎物，它们所含的营养物质会沿着食物链传递给昆虫和鱼类。轮虫的一个令人着迷的特征是它们复杂的生命周期：一些轮虫交替世代，而另一些则主要通过创建自身克隆来繁殖。依靠先进的显微成像来确定主要轮虫类群的进化历史并研究生命周期和繁殖模式如何随着该类群的进化而变化的解剖学比较将被考虑，并且研究也将得到结果。更好地表征作为该项目的一部分，将举办教育研讨会和博物馆展览，为在线数据库做出贡献，并在全国会议上举办科学研讨会。以及研究生、本科生和高中生将接受培训，对这一多样化的动物群体进行研究。该项目的目标是建立一个全面的轮虫系统发育学，重点关注最丰富、最多样化的轮虫纲。血统在这项研究将提供一个框架来测试该群体的多样化与不同繁殖模式的起源之间的关系。该项目有三个目标（1）利用分子序列数据和形态学进行全面的轮虫系统发育。形态学研究将利用传统电子显微镜、聚焦离子束扫描电子显微镜、原子力显微镜和共焦激光扫描显微镜来研究代表至少 100 个物种的形态；（2）将使用系统发育和祖先状态重建方法来研究有关轮虫生殖性状进化的问题，特别是（a）母体如何提供营养（即）。 (b) 单一动物产生有丝分裂和减数分裂卵子的能力是如何从周期性孤雌生殖进化而来的？ (c) 具有不同繁殖方式的物种产生的蛋壳在形态、化学和机械特性方面是否表现出相似性，这些是否与生活史特征相关？ (d) 某些生命周期阶段的小尺寸是否进化了不止一次？ (3) 系统发育还将用于识别单系类群，提出轮虫的预测分类，对属级别以上的分类单元进行修改或生成新的诊断，并生成物种键。此外，因为轮虫是最多样化的进化枝轮虫是颌类动物（2000 种）和较大谱系颌类动物中唯一的雌雄异体类群（约 3575 种，来自五个高等类群：毛颌类、颌口动物类、小颌类、轮虫类、棘头动物类），轮虫是深入了解颌类动物进化的理想候选者，并有助于回答有关颌类动物进化的问题。生殖多样性、颌部（例如颌类）和寄生的进化（例如，棘头动物）。该奖项反映了 NSF 的法定使命，并且通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。