The differentiation of prospective thigh mesoderm grafted beneath the apical ectodermal ridge of the wing bud in the chick embryo

摘要: Abstract Ectoderm-free isolates of prospective thigh mesoderm from chick embryos stages 17 to 27 were grafted subjacent the apical ectodermal ridge wing bud host in 18 23. Grafts donor 19 developed terminally on a high percentage cases, forming typical foot parts, covered with warty and overlapping scales armed large claws. Foot parts found less frequently when donors 20 25 employed, but number cases feathers induced at levels proximal wrist. Among which 26 provided graft, leg-specific structures only one 33 (one case showing feathers). These effects age have been correlated relationships established between graft bud. Densely cellular, pliable tissues younger readily conform contours mesodermal apex achieve intimate contact ridge. It has suggested that they contribute factors maintain an inductively active configuration are then by it form terminal leg parts. Prospective older contain considerable intercellular matrix, flexible, more displaced encroaching mesoderm; thus, formed sometimes proximally wing. Now again, however, increasing age, do remain ectoderm, but, these latter loses its normal no formed. Possibly grafts unable supply necessary inductive activity ectoderm. results their interpretation discussed respect recent reports suggest contrary role for growth limb