Figure 3.

Stage 5 chick posterior lateral plate and posterior primitive streak express heart markers when cocultured with quail anterior endoderm. Stage 5 chick PLP mesoderm was explanted and cultured either alone (lane 1) or in the presence of quail anterior endoderm (lane 2). Stage 5 chick PPS was explanted and cultured either alone (lane 3) or in the presence of quail anterior endoderm (lane 4). Cultures were grown for 48 h and harvested for RNA. Gene expression for GAPDH, Nkx-2.5, vMHC, and aMHC were assayed for both quail (Q) and chick (C) tissue by RT–PCR. Restriction site polymorphisms were employed to distinguish quail and chick transcripts.