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    Almost every cell in the body is equipped with a membrane bound, finger-like projection called a primary cilium. Cilia have been equated to cellular antennae that detect molecular signals in the environment and thus influence how cells behave. Ciliary defects, referred to as ciliopathies, are associated with a broad spectrum of human disease. A significant number of ciliopathies affect the craniofacial complex. We investigate how cilia function during the development of the precursor cells of the craniofacial skeleton, the cranial neural crest.

    current-cilia250

    Ciliopathies have craniofacial phenotypes that affect development of the midline (frontonasal prominence; f). Using both murine and avian ciliopathic models we examine how cilia influence the behaviors of various cell types that make up the craniofacial complex.

    current-2cilia250

    Glutamylated tubulin expression marking a primary cilium extended from a neural crest cell.

    Although the adult avian face bares little resemblance to the adult human face, the avian model system can, and has been used as a model for craniofacial development. The rationale behind using the avian model for studying human craniofacial development is as follows: First, early in development the faces of these two species are composed of the same facial prominences, made up of the same tissues. Second, avians and mammals use the same genetic toolkit during craniofacial development. Thus, the genes involved in specifying a bird face play similar roles in the development of a mammalian face. We explore the etiology of avian mutants with craniofacial phenotypes to identify genes that play a role in craniofacial development.

    current-2avianmutant250

    Cpp phenotype during development. (A,B) Frontal view of of d7. (C,D) Lateral views of d10 embryos. (E,F) Lateral view of d21 embryos. FNP is outlined by a dotted red line. cpp FNP marked by asterisk.

    current-avianmutant250

    Talpid2 mutation. Dotted white line outlines maxillary prominences (mx). Dotted black lines outline stomodeum and nasal pits (np). Frontonasal prominence (f), mandibular prominence (mn).

    Facial variation is the cornerstone of species-specific diversity within the Animal Kingdom. Early embryos of different species share a remarkable resemblance, begging the question, how is craniofacial diversity generated? Using various avian model systems, our lab examines the origins of species-specific facial morphogenesis from cellular, molecular and epigenetic perspectives.

    current-species_250

    Facial morphology in chick, duck and quail embryos.