Reptilian tooth and jaw development

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The fossil record for jaws and teeth of mammals and their prehistoric relatives is fairly extensive and we can see that early mammals had many reptilian characteristics. However the process by which present-day mammals lost some of these characters is not well understood at the gene level. The lack of information about reptiles from developmental or molecular studies makes it difficult to get a complete picture of evolution. Since reptiles diverged very early on from mammals the goal of our research is to compare and contrast DNA sequences of developmentally important genes amongst mammals, birds, snakes and turtles. Our aim is to appreciate the differences in gene expression patterns and gene function that may lead to specific adaptations. In this research proposal the basis for continuously replacing teeth in snakes and why turtles have lost their teeth will be investigated. In addition the development of the highly specialized jaw architecture will be studied. This will be some of the first information on snake and turtle embryonic facial development.  These studies will significantly increase our understanding of how vertebrate jaws and teeth evolved.