Can axolotls help teach us how to regenerate limbs in humans? Jessica Whited, Assistant Professor of Stem Cell and Regenerative Biology at Harvard, explains how limb regeneration in axolotls starts with a blastema. A blastema is a bud that forms at the amputation site that holds progenitor cells that are going to become the new limb. Scientists are trying to understand the steps of blastema formation in order to learn how to regenerate limbs in other species!