Fig. 1

Salamander limb regeneration. (1) Following amputation, epidermal cells migrate over the amputation surface to create a wound epidermis (turquoise). (2) The formation of a blastema (yellow), a group of progenitor cells arising from dedifferentiation and stem cell recruitment, is cued. The blastema forms at the tip of the stump beneath the wound epidermis. (3) Progenitor cells in the blastema proliferate to expand the substrate pool for the new limb cells. (4) Blastema cells differentiate, tissues are patterned, growth continues (5) to form a perfect replica of the lost limb (6)