The neurocranium develops from separate domains of pre-skeletal cells. The proposed studies will examine the hypothesis that these domains have separate developmental origins, and that their patterns of morphogenesis are specified by separate conserved signaling pathways, including Hedgehogs and Fibroblast Growth Factors. Experiments include fate mapping, time lapse analysis of neurocranial morphogenesis in the intact embryo, and genetic gain- and loss-of-function studies. Further, a new set of mutations perturbing early neurocranial patterns will be collected.