With its fascinating ability to regrow entire limbs and internal organs, the Mexican axolotl is the ideal model for studying regeneration. Scientists from the lab of Elly Tanaka at IMBA now found a factor that tells cells which part of the arm to regenerate – and used it to reprogram the identity of cells as they develop. This breakthrough for the regeneration research field has implications for tissue engineering, including in human tissues. The study was published in the journal Nature today.