RUI: Amphibian Olfaction: Morphological and Molecular Adaptation Across the Water-to-Land Transition

Cal Poly Humboldt Sponsored Programs Foundation, Arcata CA

Investigators

Abstract

Amphibian metamorphosis provides a unique opportunity to understand the changes necessary to adapt from an aquatic to a terrestrial environment. Within a single lifetime, an amphibian must undergo structural and physiological changes that allow it to make the transition that took our ancestors millions of years. The goal of this project is to determine the structural and molecular features of the amphibian nose that adapt it to smelling in air vs. water. In this study, the detailed structure of the nose in larvae and adults of a representative salamander, caecilian, and frog, and lungfish (the closet living relative of tetrapods) will be examined by histology, scanning electron microscopy, and transmission electron microscopy. In addition, the genes that code for odorant receptor proteins (the proteins that actually bind and respond to smells) will be cloned from each of these species and the stages and regions of the nose in which the genes are expressed determined. Finally, experiments with vital dyes will be used to determine which regions of the nose are exposed to water vs. air in living animals. The results from this study will provide the first broad overview of metamorphic changes in the amphibian olfactory system, and of adaptations of the adult nose for smelling water. This research will significantly enhance our understanding of the changes in the olfactory system that occurred in the ancestry of amphibians, and thus in our own ancestry; in addition, this research at an undergraduate institution (RUI) will provide an important opportunity for undergraduate to gain the experience, skills and perspective needed to attract them to, and prepare them for, a career in science.