Investigating the Mechanisms that Regulate Differences in Scleral Cartilage Morphology Amongst Teleosts

Abstract

The vertebrate ocular skeleton is comprised of the scleral ossicles and scleral cartilage. The scleral cartilage can vary drastically in morphology across vertebrate taxa, from a cup-like structure in reptiles and birds, to a narrow ring like structure around the equator of the eye in teleosts. Very little is known about the development of teleost scleral cartilage. Thus, this thesis aims to generate an understanding of the mechanisms that regulate teleost scleral cartilage development in morphology. The research presented in this thesis is divided into two main sections. A descriptive analysis of scleral cartilage development and morphology in the surface and Pachón cave morphs of the Mexican tetra (Astyanax mexicanus) as well as the zebrafish (Danio rerio) was conducted and several differences in the patterning of the development of this cartilage were found. Next, an inhibition experiment designed to disrupt FGF and TGF-ß pathway signaling during scleral cartilage development was conducted.