[Pigmentation of feather primordium achieved by grafting of retinal pigment epithelium]

Small fragments of the retinal pigmented epithelium from White Leghorn, Rhode Island Red chick embryos, and from Quail, Starling and Red Partridge embryos, were grafted into the wing bud of White Leghorn chick embryos. Retinal pigmented epithelium of White Leghorn chick embryos did not give rise to pigmentation of feather primordia in the hosts. In contrast, 60% of grafts from Rhode Island Red, Quail, Starling and Red Partridge, gave rise to feather primordia whose pigmentation was identical to that of the donors. Pigmentation depends on the fact that some graft retinal melanocytes diffuse in the wing bud of the host and reach the feather primordia. This was shown by the Feulgen technique in embryos grafted with Quail retinal pigmented epithelium, taking advantage of the fact that Quail cells possess DNA rich nucleoli. The local factors which allow the migration of the melanocytes are probably inactive on the retinal melanocytes of the White Leghorn chick embryos, whose genotype does not contain the "feather pigmentation" character.