NSF Postdoctoral Fellowship in Biology FY 2021: Uncovering the Mechanisms of Convergent Tooth Loss in Frogs

该行动资助2021财年NSF生物学博士后研究奖学金，研究基因组，环境和表型之间相互作用的生命规则的综合研究。该奖学金支持将以创新方式对生活规则领域作出贡献的研究员的研究和培训。大多数活着的脊椎动物都有牙齿。然而，在一些鱼类、爬行动物和哺乳动物中，牙齿已经完全脱落。虽然两栖动物牙齿的排列和状况研究得很少，但最近的研究表明，青蛙失去牙齿的次数超过20次。青蛙牙齿脱落的机制尚不清楚，但从进化的角度来看，研究可能的发育、遗传和环境因素将有助于了解这一过程的可预测性和可重复性。该项目的目的是确定是否存在牙齿发育所需的一组核心基因，并测试环境（温度）是否会影响牙齿发育。该奖学金将通过为本科生提供研究机会来促进导师培训。为中学教师和学生创建数字解剖学资源，利用博物馆标本提供自然选择进化的真实例子。鱼类和羊膜动物的牙齿增生是由至少四种主要的信号通路介导的，不同信号的缺失阻碍了牙齿的发育，并导致了鸟类、海龟和一些哺乳动物的牙齿脱落。由于在系统发育上广泛存在的牙齿缺失和上颚和下颚的单独进化缺失，青蛙为研究重复特征缺失的机制提供了无与伦比的机会。该研究员将使用免疫组织化学、原位杂交和转录组学来表征两栖动物的牙齿发育，并评估在独立失去牙齿的物种中是否有不同的信号阻止牙齿发育。在四足动物中，牙釉质和牙本质只存在于牙齿中，这些组织是由牙齿特异性的非多向性基因编码的蛋白质形成的。比较基因组学将用于确定牙釉质和牙本质基因是否通过新的失活突变在无牙青蛙中变得无功能。环境因素可能通过改变牙齿发育速率来影响牙齿解剖。一种实验方法将被用来测试温度这一因素是否会影响青蛙牙齿的解剖结构和表达模式。创建解剖学教育的数字资源和PI参与指导本科生和扩展将扩大项目的影响。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2021, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. Teeth are present in most living vertebrates. However, complete tooth loss has evolved in a few groups of fishes, reptiles, and mammals. Though the arrangement and condition of amphibian teeth has been poorly studied, recent work shows that frogs have lost teeth more than 20 times. The mechanisms underlying tooth loss in frogs are unknown, but examining possible developmental, genetic, and environmental factors will provide insight to how predictable and repeatable this process is from an evolutionary point of view. The aim of this project is to determine if there is a core set of genes required for tooth development, and to test if the environment (temperature) can affect tooth development. The fellowship will facilitate mentorship training by fostering research opportunities for undergraduate students. Digital anatomy resources will be created for middle school teachers and students to provide real examples of evolution through natural selection using museum specimens. The proliferation of teeth in fishes and amniotes is mediated by at least four major signaling pathways, and the loss of different signals arrests dental development and underlies tooth loss in birds, turtles, and some mammals. With phylogenetically widespread tooth loss and separate evolutionary losses on upper and lower jaws, frogs offer an unparalleled opportunity for investigating the mechanisms of repeated trait loss. The fellow will use immunohistochemistry, in situ hybridization, and transcriptomics to characterize dental development in amphibians and assess if different signals arrest tooth development among species that have independently lost teeth. Within tetrapods, enamel and dentin are found only in teeth, and these tissues are formed by proteins encoded by tooth-specific, non-pleiotropic genes. Comparative genomics will be used to identify if enamel and dentin genes have become non-functional in toothless frogs via novel inactivating mutations. Environmental factors may impact dental anatomy by altering developmental rate. An experimental approach will be used to test if one such factor, temperature, impacts the anatomy and expression patterns of frog dentition. Creation of digital resources for anatomy education and PI participation in mentoring undergraduate students and outreach will broaden the impact of the project.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.