Development of ferret limb buds in organ culture.

The forelimb bud explants from ferret embryos at days 20, 21, 22, 23 and 24 of gestation were cultured in a Trowell organ culture system. Satisfactory differentiation of the limb bud skeleton was achieved with limbs from embryos explanted at 22 days of gestation (up to 50 somites). Limb buds explanted at 20 and 21 days had poorly differentiated distal segments while those explanted at 23 and 24 days of pregnancy provided less information because chondrogenesis was already under way at the beginning of culture. Thus we conclude that the optimal time for culture of ferret limb buds is at 22 days of gestation. The level of differentiation corresponded to that obtained with mouse limb buds from 11 to 12 day embryos (40-43 somites). The time taken to achieve this level of differentiation in the ferret was 18 days compared with 6 days in the mouse.