Feather-forming capacities of the avian extra-embryonic somatopleure.
Blocks of 12.5- or 13.5-day embryonic mouse upper-lip dermis were introduced under the ectoderm of the extra-embryonic area of 2- to 3-day chick or duck embryos. Two kinds of ectopic cutaneous appendages were produced: either arrested feathers alone, or arrested feathers and full-grown feathers. The former developed in the ectoderm overlying the implanted mouse dermal cells, the latter formed in their close vicinity, but contained host dermal cells exclusively. Thus, avian extra-embryonic somatopleure, both ectoderm and mesoderm, possesses the information for feather development: the extra-embryonic ectoderm, if it is brought in contace with an appendage-forming dermis, is able to respond to the dermal induction by initiating feather morphogenesis; the extra-embryonic mesoderm, if it is experimentally transformed into a dense dermis, can express its feather-forming capacity by specifying feather tract morphology and barb-ridge number, thus leading to the acievement of feather morphogenesis.
D000818:Animals; D002642:Chick Embryo; D004372:Ducks; D004475:Ectoderm / Q000166:cytology; D004817:Epidermis / Q000637:transplantation; D005241:Feathers / Q000196:embryology*; D014183:Transplantation, Heterologous