Cardiac neural crest migrates to the pharynx and is responsible for normal development of the arterial pole, the great arteries, and the aorticopulmonary septum. When the neural crest is ablated, signaling of FGF8 in the pharynx increases significantly. We therefore hypothesize that FGF8 is mediating CNC migration via positive chemotaxis. In order to test this hypothesis, I will place a neural crest explant on the area opaca of a New culture near a bead soaked in FGF8 protein, or a control. Using fluorescent and time-lapse imaging, I will visualize the migration of CNC cells. I hypothesize that the CNC cells will migrate towards the exogenous source of FGF8 (the bead). I will also use other signaling factors to test their effect and I will perturb the system using a dominant negative-FGF receptor in order to confirm the importance of FGF8.