Fig. 1. In vitro differentiation potential of cranial paraxial mesoderm and splanchnic mesoderm in chick embryos. (A) Dissected cranial paraxial mesoderm (CPM, purple) and splanchnic mesoderm (SpM, orange) of a stage 10 chick embryo: (A1) Ventral view; (A2) following the removal of the linear heart tube; (A3) transverse section of the embryo (dotted line in A2). (B,C) CPM and SpM explants were dissected from stage 10 embryos. RNA was harvested from the explants either immediately (0) or after 3 days in culture. RT-PCR analysis was performed for the indicated cardiac markers and signaling molecules. Although cranial paraxial mesoderm explants underwent myogenesis in culture (n=17/20), splanchnic mesoderm explants underwent cardiogenesis (n=20/20). T, total chick RNA; da, dorsal aorta; nc, notochord; nt, neural tube; oft, outflow tract; ph, pharynx.