Early expression of muscle-specific molecules in avian embryos.

With an antibody against whole embryonic chick heart, avian embryos of different stages were stained from beginning of cardiogenesis on. The earliest positive staining was encountered in a stage where heart tissue was already morphologically recognizable. This was also the case for myotomes and extrinsic eye muscles. Positive staining with anti-desmin of the same stages was possible slightly later. At the onset anti-desmin showed a staining pattern different from that of anti-heart staining.