Determination, differentiation and migration of non-neuronal neural crest derived cells.

After heterotopically grafting premigratory neural crest cells from quail embryos to the wing buds of chicken embryos, Schwann cells, non-epidermal melanocytes and epidermal melanocytes develop in the wings of the host embryos. This indicates that these neural crest derived cell populations are determined before the onset of emigration of neural crest cells from the crest. Epidermal melanocytes of donor origin are found essentially distally from the grafts, whereas non-epidermal melanocytes and Schwann cells are found proximally and distally therefrom. If the apical ectodermal ridge is removed from wing buds that have received a graft of neural crest cells, the directionality of the migration of epidermal melanocytes is lost. This indicates that the apical ectodermal ridge might account for the directional movement of epidermal melanoblasts. This situation is compared to myoblasts that behave in a similar way within the avian embryonic wing bud.