Fig. 7. Control (A,B, orthotopic) and trunk-into-head (C,E, lateral half somite; D, medial half somite) transplantations. Embryos were fixed at stage 28-30 and double stained with F59, to show myosin heavy chain (purple), and QCPN, to show quail nuclei (brown). (A) The labels are on the unoperated side. (B) Graft-derived cells contributing to the lateral rectus (box in A). (C) A lateral rectus muscle in which nearly all cells are derived from the transplant. Blazes of unlabeled intramuscular cells are connective tissues derived from neural crest cells. (D) Dorsal oblique muscle, and (E) lateral rectus and proximal first branchial arch (BA1) muscles, formed by grafted trunk mesoderm. Proximal BA1 muscles normally initiate MyHC synthesis at a later stage, and graft-derived myocytes follow this head timetable.