Scientists have discovered the secrets behind electric fish, using genetic studies to reveal how the creatures developed an organ that can unleash a wicked jolt.
They unveiled a genetic blueprint of the South American electric eel - which can zap humans with up to 600 volts - as well as detailed genetic data on two other types of electric fish.
Even though six groups of electric fish have evolved independently in far-flung places like the Amazon and murky marine environments, they all seem to have reached into the same "genetic toolbox" to fashion their electricity-generating organ.
The new study found that various electric fish rely on the same genes and biological pathways to build their electric organs from skeletal muscle, despite the different appearance and body location of their organs.
"It really is something unique in the animal kingdom," Jason Gallant, professor of zoology at Michigan State University in the United States, said.
There are hundreds of species of electric fish, with varying degrees of electric power. Those like the electric eel possess a powerful jolt used to stun or kill prey and repel enemies.
Scientists have wondered about how these fish first acquired electric powers and how this characteristic emerged six times in groups not closely related to one another. Gallant said: "Electric organs start out their lives as muscle precursor cells. Through a series of developmental steps, they become larger, more electrically excitable and lose their ability to contract."