Pax Gene Expression in the Development of Sensory Systems in the Moon Jellyfish (Aurelia surita)

The moon jellyfish Aurelia aurita belongs to the phyla Cnidaria, which includes animals such as sea anemones, corals, and jellyfish. While generally thought to be morphologically simple, some members of this phylum, such as Aurelia, have sophisticated sensory structures, including simple eyes. Recent phylogenetic studies have grouped cnidarians as a sister group to the bilaterally symmetric metazoans (the Bilateria), which encompasses 99% of all living species. Studies have shown that the same genes expressed in bilaterian sensory development are also found in non-bilaterian taxa, like cnidarians. It is therefore important to study developmental genes to understand the relationship between cnidarians and the bilaterians regarding the early evolution of sensory structures. This project aims to spatially and temporally trace paired-type homeobox gene expression in A. aurita using fluorescence in situ hybridization (FISH) with a focus on their role in the development of sensory systems. Particular attention will be placed on the relationship between the PaxA and PaxB expression pattern in A. aurita’s rhopalia and tentacle formation, and their relationship to the homologous gene Pax6, which is known for its role in bilaterian eye development. The additional association of Pax genes with cnidocytes, a single cell known to have photoreceptive properties in the absence of any eye-like sensory organ, will also be examined.