Meeting Abstract

100.12  Sunday, Jan. 6  Development of the maxillary dentition in teleost fish ATUKORALLAYA, S; WATERFIELD, V; FRANZ-ODENDAAL, TA*; Mount Saint Vincent Univ; Mount Saint Vincent Univ; Mount Saint Vincent Univ tamara.franz-odendaal@msvu.ca

During the vertebrate craniofacial development the first pharyngeal arch forms two prominences which eventually give rise to the maxillary and mandibular bones. In most vertebrates, including humans, maxillary and mandibular bones together with the premaxillary bone have teeth. Usually, odontogenesis in the maxillary and mandibular jaws initiate simultaneously, however in the Mexican tetra (Astyanax mexicanus) this process appears to be uncoupled. This small fresh water teleost fish is a good animal model to study the evolutionary development of craniofacial structures. Tetra fish have teeth on the mandibular, maxillary and premaxillary bones. The initiation of oral teeth is first observed at 44 hpf in the mandible and in the premaxilla, and the first oral teeth start to erupt around the 5 dpf. Interestingly, the maxillary teeth erupt much later in life at around 100 dpf. In this study we sought to find the cause for the temporal difference in tooth development in these two bones. Whole mount bone staining and histology were conducted to identify the tooth development stages in M. tetra in selected age groups. The gene regulatory network behind this delay in maxillary tooth development was analysed using in situ hybridization. Our study will shed light on the developmental events leading to odontogenesis in the maxillary bone in this species and will broaden our understanding of tooth development events that occur in the first pharyngeal arch derived bones in vertebrates.