NSF Postdoctoral Fellowship in Biology FY 2018: Evolution and development of chemosensory systems in tetrapods

本行动资助美国国家科学基金会2018年度生物学博士后研究奖学金，利用生物馆藏进行研究。该奖学金支持研究和培训将以创新的方式利用生物收集的研究员。劳雷尔·约赫的这项研究计划的题目是“四足动物化学感觉系统的进化和发展”。大多数动物只有一个嗅觉系统来处理化学信号，帮助它们寻找食物和配偶，以及躲避捕食者和有毒物质。这位研究员正在研究为什么四足动物在鼻子里发展出一种叫做犁鼻系统的二级嗅觉系统。关于为什么两种嗅觉系统首先进化的解释是不完整的，并且被猜测混淆了。使情况进一步复杂化的是，犁鼻系统在许多独立的谱系中已经减少或消失。该研究员将应用创新和非破坏性染色方法对博物馆标本进行量化和表征这两种嗅觉系统功能的变化，从胚胎发育的鼻腔到拥有这两种系统的物种的完全发育的鼻子，包括那些失去了马鼻系统的物种。了解这两个系统是如何进化的，以及为什么犁鼻系统在某些物种中消失了，可以帮助我们理解化学感觉的进化和发展，也可以帮助我们理解一般的感觉进化。通过对开创性方法和新学科的接触和培训，这将有助于塑造研究员未来的研究计划，该研究将为研究员作为独立研究科学家的职业生涯做好准备。大多数已知的嗅觉分子和发育机制来自模式生物。本项目将新的染色和成像方法应用于成人和胚胎非模式生物博物馆标本，以测试长期存在的假说，即为什么在一些四足动物中，表鼻系统的选择已经放松，而在其他四足动物中，选择仍然保持良好。首先，该研究员将使用非破坏性染色技术对博物馆标本的多样性进行量化，以确定已知具有犁鼻功能差异的生物群体中不同嗅觉结构的大小和体积。根据这些数据，研究人员可以测试一些假设，比如为什么有些物种有犁鼻系统，而有些没有，比如它们有水生的生活方式，或者是昼行性的。其次，该研究员将对存在功能变异的生物体群体的鼻腔发育进行比较胚胎学研究，确定可能发生退化的关键个体发育阶段。第三，在变异被认为发生的阶段，研究员将应用比较转录组学来确定这种变异的分子基础。该项目将建立一个新项目，将纽黑文社区学院的学生与耶鲁大学的研究项目联系起来。这种拓展使学生经常没有直接接触研究机会的实践学习活动和研究经验。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 2018, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. The title of the research plan for this fellowship to Laurel Yohe is "evolution and development of chemosensory systems in tetrapods". Most animals have only a single smell system for processing chemical signals that help them find food and mates, as well as avoid predators and noxious substances. This fellow is investigating the reasons why tetrapods developed a secondary olfactory sense system in their nose called the vomeronasal system. Explanations for why two smell systems evolved in the first place are incomplete and confounded by speculation. To complicate the story further, the vomeronasal system has been reduced or lost in many lineages independently. The fellow will apply innovative and non-destructive staining methods to museum specimens to quantify and characterize the variation in these two olfactory systems' function, from the developing nasal cavities of embryos to fully developed noses of species that possess these two systems, including those species that have lost the vomeronasal system. Understanding how these two systems evolved, and why the vomeronasal system is lost in some species, can help our understanding of chemosensory evolution and development specifically, but can also help us to understand sensory evolution in general. This study will prepare the fellow for a career as an independent research scientist, through the exposure and training of pioneering methods and new disciplines that will help shape the future research program of the fellow.The majority of what is known about the molecular and developmental mechanisms of smell comes from model organisms. This project applies new staining and imaging methods to both adult and embryonic non-model organism museum specimens to test longstanding hypotheses on why selection on the vomeronasal system has relaxed in some tetrapods but remains well conserved in others. First, the fellow will use a non-destructive staining technology to a diversity of museum specimens to quantify the sizes and volumes of different olfactory structures in groups of organisms that are known to have differences in vomeronasal function. From this data, the fellow can test hypotheses for why some species have the vomeronasal system and some do not, such as having an aquatic lifestyle or being diurnal. Second, the fellow will perform a comparative embryology study of nasal cavity development in groups of organisms where variation in function exists, identifying key ontogenetic stages in which vestigialization may occur. Third, at the stages in which variation is thought to occur, the fellow will apply comparative transcriptomics to identify the molecular basis for this variation. The project will establish a new program that links students from New Haven's community colleges to participate in research projects at Yale. This outreach exposes students that often do not have direct access to research opportunities to hands-on learning activities and research experiences.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.