Meeting Abstract
Understanding normal craniofacial morphogenesis in a wide range of vertebrates will shed light on whether similar or distinct processes are modified to generate the remarkable diversity in adult form. Understanding the developmental bases of craniofacial malformations will shed further light on potentially sensitive developmental process that are most easily affected by genetic and environmental perturbations. To date, the embryology and molecular regulation of craniofacial development has not been examined in squamates, lizards and snakes. Using a battery of imaging techniques–uCT scanning, fluorescent in situ, and electron microscopy–we have investigated craniofacial morphogenesis in the lizard, Anolis sagrei. Compared to more commonly studied species, chickens and mice, we observe a unique shape to the craniofacial prominences. The expression of key patterning molecules, Shh, Fgf8, and Bmp4, parallels this unique morphology. We have not observed a distinct frontal ectodermal zone. We previously reported an increased rate of craniofacial malformations in lizard embryos that experienced thermal stress. We have further narrowed this window to the period of facial morphogenesis, during the peak period of cell proliferation and facial prominence outgrowth. Increases in the severity or duration of the thermal insult generate more severe craniofacial malformations. Our preliminary data suggest that these malformations are the result of disrupted Shh signaling. Together these results increase our understanding of the molecular regulation of vertebrate craniofacial development and on a thermally sensitive processes of craniofacial development that may be common among vertebrates.
