STREELMAN, Todd; Georgia Institute of Technology: Genetics and Development of the Cichlid Dentition

A general goal of evolutionary biology is to understand how diversity is generated and maintained in natural populations, and yet this is something we know little about at the molecular level. This is an apposite description of the state of knowledge regarding the developmental genetics of the vertebrate dentition: we know a good bit about early stages of odontogenesis (e.g., where teeth develop) and less about later modifications of shape (cusp number). I introduce a system useful to study the genetic and developmental basis of tooth shape diversity. The myriad species of cichlid fish from East Africa differ in their feeding behaviors and in the shapes of their jaws and teeth. We have used quantitative genetic methods to estimate the number of genes controlling tooth shape in a hybrid cross between cichlid species with divergent trophic morphologies and used in situ hybridization to investigate gene expression in the cichlid dentition. Results suggest that differences in the shape of cichlid teeth are influenced by a modest number of genetic factors and that the cichlid dental transcriptome is complex, but not unlike that of other vertebrates.