The Evolution of Senses: My Research Journey into the Nervous System of Cnidaria

Molly Hartley, University of New Hampshire, Durham

Abstract

Our understanding of the evolutionary history of animals is improving, but knowledge of the ancient sensory systems that early animals used to interact with their environments is still largely unknown. Using molecular cloning and in situ hybridization staining procedures, I was able to test the hypothesis that some senses evolved prior to the evolution of animals with bilateral symmetry. My data provides evidence that cnidarians can taste using genes that are closely related to human taste receptors. This finding changes our current understanding of when tasteevolved by hundreds of millions of years. The in situ hybridization results also demonstrated co-localization, or overlap, of the expression of taste and photosensitivity genes, which provides preliminary evidence that cnidarians use a polymodal sensory-motor (PSM) neuron to sense light and chemical cues (“tastes”) to coordinate their feeding behavior. The cDNA constructs I have produced will also provide further biochemical insights into their function. My long-term research projects have taught me about the process of making scientific discoveries, and I hope to continue conducting research throughout my career.