If you’ve ever owned a fish tank, you’re probably familiar with planaria, or flatworms as they are more commonly known, and you probably don’t like them. They are usually about half an inch long and multiply at an alarming rate in your tank. Most aquarists regard them as pests. But for some research scientists they are literally the most interesting creatures on Earth. What makes a planarian so remarkable becomes apparent if you cut one in half: it grows back into two flatworms. And it’s not just a head and a tail that are separately staying alive; it’s two complete, new flatworms, each with its own new head or tail. Even more strangely, if you cut a planarian up into multiple pieces, each fragment will regrow exactly the parts it needs to transform into a new, perfect worm.

… Michael Levin, Distinguished Professor at the Tufts University Department of Biology in Massachusetts, has studied planaria extensively. His aim is to identify the mechanism by which the cells in each fragment of worm know what is missing, know how to rebuild the organs it needs, and know when to stop. He believes that answering these questions is the key to future advances in regenerative medicine and synthetic bioengineering. Levin’s hypothesis is that it is bioelectricity – the tiny electric currents which are generated by biological processes – which allows the cells in a planarian to communicate with each other. The currents are not just allowing communication, they allow cells to form networks with memory and decision-making computational capacities.

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