AN INTEGRATED EXPERIMENTAL-STUDY OF ENDODERM FORMATION IN AVIAN EMBRYOS

摘要: The formation of the endoderm during primitive streak stages in avian embryos was studied by combining several following techniques for each embryo. These included microsurgery, time-lapse filming, use chick-quail chimaeras, tritiated thymidine autoradiography and a novel technique identifying morphology cells after small pieces tissue from known areas had been maintained culture 24 h. Using these we have confirmed that ventral layer early chick embryo receives contributions both marginal central regions area pellucida. former seems to consist yolky derived germ wall, whilst latter consists smaller, less more dorsal layers movement lower anteriorly appears be dependent upon mechanical constraints imposed it expanding caudal regions. extent two determined as function stage presence or absence layer, findings are discussed light existing literature.