All animals capable of regenerating a lost body part, from an organ or a limb to the whole organism, use a common set of genes. This is the striking discovery of a team of researchers from the Center for Complexity and Biosystems of the University of Milan, led by Caterina La Porta. They analyzed the genetic activity in regenerating tissues from widely different speciesâfrom hydra to mice. They found that some of the genes active at the beginning of the regeneration process are the same in very different species, including mammals which have lost this function during evolution, except for the restoration of the liver. The discovery of this shared genetic signature is of great importance to understand how regeneration evolved and could be useful for future regeneration therapies.