LIZARDS AND FLATWORMS CAN DO IT, SO WHY CAN’T WE? Persuading the Body to Regenerate Its Limbs. And no CRISPR needed: “The most astonishing part was that Levin hadn’t touched the planarian’s genome. Instead, he’d changed the electrical signals among the worm’s cells. Levin explained that, by altering this electric patterning, he’d revised the organism’s ‘memory’ of what it was supposed to look like. In essence, he’d reprogrammed the worm’s body—and, if he wanted to, he could switch it back.”