When Salamanders Regrow Arms and Humans Form Scars: The 300-Million-Year Divergence
In 1768, Lazzaro Spallanzani published something that sounded like science fiction: salamanders could regrow amputated limbs. Not just heal the wound—actually regenerate a complete, functional limb with bones, muscles, nerves, and blood vessels. Over 250 years later, humans still cannot do this. Lose a finger, and it is gone forever. But dig beneath this apparent biological unfairness, and you find a story of evolutionary trade-offs, molecular complexity, and a surprising fact: the genes for regeneration never left us. ...