Hydra genetically reprograms skin cells after losing its nerve

After losing its nervous system, the freshwater polyp adapts its skin cells to make them act like nerve cells

In Greek mythology, the Hydra was a gigantic, snake-like monster with nine heads and poisonous blood and breath, which lurked in the swamps of Lerna. Heracles was sent to destroy the beast as one of his twelve labours, but when he decapitated one of its heads, two more grew back in its place. He eventually defeated it with the help of his trusty nephew Iolaus, however, by burning out the severed roots with firebrands to prevent the regrowth, then decapitating its one immortal head and burying it under a heavy rock.

The real Hydra has regenerative capacities that surpass those of its mythological namesake. When it is dismembered, any fragment of its body can regenerate to form a completely new individual, and it can even remain alive after its entire nervous system has been lost. Researchers in Switzerland now report that it does so by adapting its skin cells to make them behave more like neurons. Their findings provide clues about how nerve cells first evolved, billions of years ago.