Figure 1.

Key morphological events of vertebrate limb regeneration. Following amputation, epidermal cells from the surface of the stump rapidly migrate to cover the wound (1), forming the apical epidermal cap (AEC, red). Stump cells are used to create a blastema (blue) beneath the AEC (2). Blastema cells proliferate and the structure acquires a cone-shaped morphology (3). Undifferentiated blastema cells begin to differentiate into various cell-types within the newly formed limb (4). The new portion continues to grow. Once patterning and growth are complete, a perfectly functional new limb has been regenerated (5).