Coordinated timing of tooth and jaw development

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As teeth and jaws grow they must fit together to work properly and allow an animal to eat. Because teeth sit within the jawbone, any developmental or evolutionary changes in jaw shape or size will invariably affect the teeth and vice versa. To understand how a body part develops is to understand how it may have evolved. It is not known how the timing of tooth and jaw development is coordinated such that these parts "fit" together properly during pre- and postnatal growth. My lab aims to explain how the pace of tooth and jaw development has evolved in a coordinated way. One option is that the timing of tooth development is controlled by signals from the jaw tissues, and vice versa. However, good evidence suggests that the opposite is true: the pace of tooth and jaw development has been naturally selected to run in parallel with no cross-talk between tooth and jaw tissues. My proposal aims to tackle this research question using complimentary genetic, statistical and imaging data alongside mammalian models at various stages of pre- and postnatal development. To test if teeth and jaws each have their own non-interacting network of genetic controls with respect to developmental timing, my lab will analyze gene expression in developing tooth and jaw tissues. Using high-resolution 3D computed-tomography (CT) images of jaws and teeth in tandem with statistical tools we will also test if the times at which teeth start to develop are dictated by how much space exists for them in the developing jawbone. Our research will begin to fill a fundamental gap in scientific knowledge by helping to explain how jaw and tooth development is coordinated in time. This insight should further clarify how teeth and jaws have developed and evolved such an amazing variety of different yet functional forms across living and extinct mammals.