Inter-breed, intra-breed and autoplastic chimerae of the domestic fowl.

Abstract

IN 1956 one of us1 developed a technique of grafting the forebrain region on the chicken embryo, which then underwent more or less normal development as a chimera2,3. Only a few of the chimeric embryos hatched and lived (Table 1). In the work reported here, three random-bred breeds of chicken were used: Barred Rock, White Leghorn and Rhode Island Red. The majority of the chimeric birds which hatched developed from reciprocal graftings between the embryos of Rhode Island Red and White Leghorn breeds. 502 inter-breed, 19 intra-breed and 68 autoplastic operations were performed. Fourteen inter-breed, one intra-breed and five autoplastic birds hatched. As these figures show, the percentage of individuals able to hatch in the inter-breed chimeric embryos was very low, whereas in the autografted embryos, although the number of embryos operated on was small, this percentage was considerably higher. One of the reasons for this is the difficulty of matching the transection plane on the recipient with that of the donor of the graft. As the self-regulating capacity of the embryo at the operation stage is quite limited, the appearance of supernumerary parts is the result. Such embryos never hatch.