Scientists studying axolotls, zebrafish, and mice have uncovered a shared set of genes that may one day help humans regrow lost limbs. By identifying powerful “SP genes” involved in regeneration, researchers discovered that disabling these genes stopped proper bone regrowth in salamanders and mice. They then used a gene therapy inspired by zebrafish biology to partially restore regeneration in mice, marking a major step toward future treatments that could replace damaged limbs with living tissue instead of prosthetics.