In vitro differentiation of the Japanese quail secondary palate

Differentiation of the Japanese quail secondary palate was studied in vitro. Results indicated that the medial edge epithelia (MEE) of quail were capable of full differentiation in vitro from a very early age. In contrast to in vitro mammalian palatal development, the quail palatal processes never fused. The cells of the MEE in the quail continued to divide, and the cyclic adenosine monophosphate (AMP) levels in the quail palatal tissues remained constant during development. In contrast to in vitro differentiation of MEE in the chick palate, the quail palatal MEE differentiated to parakeratinized epithelium. The results suggest that: (1) the programming of events of MEE differentiation in birds is different from that in mammals, (2) intraspecies differences in the MEE biology of chick and quail palate are intrinsic to the palate, not the environment, and (3) an inverse relationship between the levels of cyclic AMP and the synthesis of DNA in the MEE may exist during secondary palate development, which in turn may regulate the fate of the MEE in birds and mammals.