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

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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.