Meeting Abstract

P2-76    The genetic basis of dental patterning in cave-dwelling fish Amaismeier, AM; Powers, AK*; Anyonge, W; Tabin, C; Xavier University, Department of Biology; Harvard Medical School, Blavatnik Institute of Genetics; Xavier University, Department of Biology; Harvard Medical School, Blavatnik Institute of Genetics amaismeiera@xavier.edu

Our understanding of the genes involved in tooth patterning is limited by the challenges of in utero studies in mammals. Recently, studies in evolutionary model systems such as sharks, lizards and fish have shed light on tooth development. Cavefish (Astyanax mexicanus) serve as an excellent model for tooth formation for several reasons: 1) the existence of a surface-dwelling morph of the same species with differing morphology, 2) genetic association studies can be performed from hybrid crosses, and 3) A. mexicanus are hardy and breed readily in the lab environment. Cavefish serve as an excellent model for understanding genes involved in early initiation and patterning of teeth as they show an increase in tooth number and difference in tooth size and cusp number compared to surface fish. Here, we present a study investigating the dentition of a F₂ hybrid A. mexicanus pedigree. Phenotypic traits such as tooth number, cusp number, tooth length, tooth width, diastema, and replacement teeth were quantified from cleared-and-stained specimen images. Orofacial phenotypes were analyzed through Quantitative Trait Loci (QTL), from which 11 traits were mapped and found to be significantly-associated with regions of the A. mexicanus genome. For each associated genetic marker, the BLAST algorithm was used to align the genetic markers to a specific region of the genome. A Gene Ontology (GO) term analysis was used to uncover genes known to be associated with orofacial traits. From the GO term analysis, we compiled a list of candidate genes to be further analyzed with molecular techniques in the lab. Taken together, this work establishes A. mexicanus as a model for tooth development, from which we can make progress in the discovery of genes involved in tooth size, shape, and patterning.