Chop off the leg of a salamander or newt, and the limb will slowly grow back. How the wounded stump regrows into a leg is poorly understood, but now researchers have identified a key protein behind this regenerative power.
Studying animals with such regenerative abilities might reveal ways to induce feats of radical self-healing in people, some scientists believe.
When a newt's leg is severed, muscle cells at the site of injury revert to a less-specialized state, becoming stem cells. These stem cells then divide and grow to regenerate the limb.