If you snip a bit of DNA from a vegetable, but add no new genes, does that vegetable qualify as a genetically modified organism, or GMO?

It's a hot question for government regulators, and it's no longer theoretical. Yinong Yang, a researcher at Penn State University, used a popular gene editing tool called CRISPR/Cas9 to snip out a tiny piece of DNA from one particular gene in a white button mushroom. This disables the gene, which in turn reduces the mushroom's production of an enzyme called polyphenol oxidase. As a result, the mushroom doesn't turn brown so quickly.

This may sound familiar. Scientists have also created non-browning versions of apples and potatoes. But those crops were considered GMOs, because scientists inserted new, slightly altered genes into those plants in order to "silence" the natural gene.

Last fall, Yang sent a letter to the U.S. Department of Agriculture, asking if his mushroom would be subject to regulation by the USDA. This week, the USDA sent its answer: No.

It's the first time the USDA has looked at a crop that has been edited using the CRISPR technique, and it's attracting a lot of attention, because it could be the first of many.

It does not mean, however, that the mushroom — or other foods — would necessarily avoid all government scrutiny. Companies that are bringing GMOs to market have, until now, submitted those products to the Food and Drug Administration for review.

"Anything for food or feed consumption, usually the company submits the data to FDA for approval," says Yang. But he also notes that "this process is voluntary, not mandatory."

Gregory Jaffe, biotechnology program coordinator at the Center for Science in the Public Interest, says the case of the mushroom illustrates the holes in the government's current regulatory process. "The regulatory system is not science-based, but trigger-based," he says.

The USDA only regulates crops where there is a risk that the new variety could become a weed or a "pest" to other plants. "You could have a situation where a crop may actually have some risk, but doesn't get regulated by USDA, and you could have things that don't have any risk, but which are regulated" because they incorporate genes, for instance, from a plant virus.

The White House has announced a review of the entire regulatory framework for genetically modified crops. As part of that, the National Academy of Sciences is convening a meeting on April 18 to look at new biotechnologies and ways to regulate them.

UPDATE, April 15, 5 P.M.: Douglas Gurian-Sherman, with the Center for Food Safety, a nonprofit group that has campaigned against genetically engineered crops, says the lack of formal regulatory review of gene-edited crops is disturbing. For one thing, it makes it difficult to know exactly what's been done to the crop. "The company can just keep its data to itself," he says.

Gene editing techniques such as CRISPR, he says, can create genetic alterations that are not fully predictable. "Because of the newness of the technology, we think that it should be regulated as a technology," and all crops created by gene editing tools like CRISPR should require government approval.

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