Biologists lopped off the head and tail of the Mediterranean flatworm on the right and then helped them to regrow. The animal kingdom often exceeds fiction with abundant examples of insects and molluscs able to replace severed legs, tentacles and siphons. Switching-on a gene called zic1 activated the process that allowed the flatworm to regrow its head and tail (left) using its own pluripotent stem cells. Key to the mechanism of regrowth is a protein called Notum encoded by the zic1 gene. Notum controls communication between cells and is normally present in developing embryos. Although some of the mystery remains, future medicine will seek to manipulate this mechanism to heal damaged tissue, and even to grow back lost body parts. Whether the flatworm's personality changed as a result of the head change remains an open question though.
Written by Tristan Farrow
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