The science fiction-like ability of some animals like lizards and zebrafish to grow back lost body parts has long mystified scientists hoping to copy the feat to treat humans with injured limbs. Biologists studying zebrafish able to grow back severed fins – a developing fin is shown – revealed the two key steps in the hitherto mysterious process. Bone cells in the vicinity of the injury first signal to each other to reset themselves back into progenitor cells that multiply until they replace the lost fin, as if in a developing embryo. A second process then kicks-in to turn the new cells back into mature hard cells that give the fin its solid appearance. While this second step is already used to heal injured bones in patients after operations, with mixed results, future therapies could copy the whole regeneration process.
Written by Tristan Farrow