Bioelectrical signals direct blobs of cells to transform into any part of the body. Harnessing it can create freakish animals with two heads - and may spark a medical revolution

Bioelectricity shapes anatomy Steward Patience/www.StuartPatience.co.uk

FROM the tail of the leafy sea-dragon to the toucan’s beak and the human hand, each and every one of the myriad forms assumed by living things starts out as an amorphous blob of cells. It’s one of the biggest mysteries of life: what choreographs billions of cells to create so many intricate anatomical patterns, what Charles Darwin preferred to call “endless forms most beautiful”?

It’s all in the genes, of course. Except that it’s not. These days, biologists are investigating a long-overlooked aspect of shape control: the electrical signals that constantly crackle between cells. Whether in embryonic development or repairing parts of the body, bioelectricity seems have a big say in telling cells how to grow and where to go. It also appears to play an important role in the astonishing knack some creatures have to regrow lost or damaged limbs.

If we can figure out precisely how it encodes patterns of tissue formation – if we can crack the “bioelectric code” – the possibilities would be startling. Not only will we get a deeper understanding of evolutionary change, we could revolutionise tissue engineering and regenerative medicine. “Once we know how anatomy is encoded, we will be able to make shapes on demand,” says Michael Levin, a developmental biologist at Tufts University in Medford, Massachusetts.

We’ve known for a while that when it comes to development, the process that takes you from a single cell to a fully fledged organism, DNA only goes so far. “If you were to show someone the completed genome of a creature, and you didn’t allow them to compare it with the genome of something they …