You’ve probably heard the hype: CRISPR will revolutionize biotech, cure disease, resurrect extinct species, and even create new and (not so) improved humans. But what is CRISPR—and what’s it doing in our food? The first genetically modified crops, also known as GMOs, were labeled “Frankenfoods” by critics and are banned in the European Union. Can CRISPR succeed where fish tomatoes failed? And what’s yogurt got to do with it? Listen in this episode for the CRISPR story you haven’t heard.

When modern genetic modification began in the 1970s, scientists typically took a gene that conferred desirable properties in one species (say, cold tolerance in a winter flounder) and blasted it into the genome of another species (say, a tomato). The hope was that the alien gene would be incorporated, albeit at random, into the host plant’s DNA, and that the resulting hybrid would gain a useful new function. Frost-resistant fish tomatoes, as it happens, were not particularly successful in field trials, and they became a symbol for everything that critics—of which there were many—saw as wrong with genetically modified foods.

Next-generation gene editing, using CRISPR, promises to be far more precise, faster, and cheaper. As Jennifer Kuzma, the co-director of the Genetic Engineering and Society Center at North Carolina State University, explained it to Gastropod, if DNA is a book, CRISPR is like a pen. “You can go in and you can edit the letters in a word, or you can change different phrases, or you can edit whole paragraphs at very specific locations,” she said. “Whereas with first-generation transgenic techniques, it was essentially throwing a new paragraph into a book.”