Developing the Common Reef Sponge to Study the Only Non-neural Animal Eye

Grant Winner

Dean

Abstract

This study represents a new collaborative marine physiology project to study the genetic mechanisms of light sensitivity in marine sponges. While adult sponges are sessile, their larvae possess light sensitive rings of pigment that mediate phototactic swimming. Sponges probably have no nervous systems or opsin genes, so the unknown molecular components of sponge phototaxis must differ fundamentally from those in other animals, inspiring questions sensory system functions. To determine the presence of the only non-neural animal eye, we propose to investigate Callyspongia vaginalis because it possesses phototactic larvae with pigment ring eyes and is very common in Florida. This sponge has been collected before in the area, and therefore our proposal is feasible, practical and relatively low cost. More importantly, learning to collect these animals will lead to future integrative, fundamental, and fundable research. With knowledge of how to obtain larvae, we will be able to conduct genetic, physiological, and behavioral tests supporting the first Cryptochrome-based eye of any animal. We aim to test the following hypotheses: a) these techniques can be applied to the larvae of the common reef sponge to test whether Cryptochrome is indeed the light receptor and b) Cryptochrome sequences are prevalent in other local reef sponge species. Because of the sensitivity of neurophysiology, these experiments would be most easily conducted at both NSU and UC-Irvine (UCI), and we anticipate that larvae can be shipped from NSU to UCI for experiments. Understanding the function of this non-opsin, non-neural eye will allow fundamental new insights into sensory biology, will illustrate an amazing case of convergent evolution of an eye, and could inspire efficient coupling of robotic light sensors and motion drivers. With positive results from this project and the new California collaborations, we will have a strong likelihood of providing preliminary data essential to pursue larger external grants.