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Scientists at Pennsylvania State University used the gene-altering technique Crispr to create a white-button mushroom that doesn't turn brown as quickly, meaning it can sit in your fridge for longer than usual. And that mushroom may well be in your fridge soon. Last week, the U.S. Department of Agriculture sent the lab a letter giving the mushrooms a thumbs up, thus, for the first time, clearing a food altered with Crispr.


This is a really big deal—and not just for mushroom lovers.

“The new technology,” University of Minnesota biologist Daniel F. Voytas told Scientific American last month, “is necessitating a rethinking of what a GMO is.”


Typically, when scientists have sought to genetically modify crops, they've relied on techniques that splice genes from one species into another—adding, for example, a bit of flounder DNA to a tomato to help it survive colder temperatures.

For obvious reasons, this notion of a mutant fish-tomato gives some people the willies, even though the vast majority of scientists say that it is perfectly safe. But Crispr, which allows scientists to cut and paste gene sequences more easily than ever, means scientists can more easily alter crops without adding genes from another species. To prevent those white button mushrooms from browning, for example, scientists just had to knock out the bit of DNA responsible for making them turn brown when you cut them. No Frankenfishmushroom here.

Some scientists have argued that this makes foods engineered using Crispr fundamentally different from the transgenic engineering responsible for crops like that tomato with flounder DNA or Monsanto’s Roundup-resistant corn. This process, they say, is a less biologically-disruptive means of altering plants.

The USDA, it seems, may be inclined to agree. In its letter to Yinong Yang, the plant pathologist at Pennsylvania State University responsible for the newly engineered mushroom crop, it wrote that because the new mushroom “does not contain any introduced genetic material” it isn't even subject to the agency's GMO regulations.


Since the 1990s, the USDA has regulated which genetically modified crops can head to market, the thinking being that crops with foreign DNA could accidentally cause environmental harm. But a mushroom that has simply had some of its DNA deleted, the agency said, seems to present no such threat.

Anti-GMO activists have been zealously against crop modification even though the vast majority of the scientific community believes that they are not inherently harmful, so there's no telling whether Crispr will change their stance.


Gary Ruskin, the co-director of U.S. Right to Know, a consumer advocacy group that has come out largely against the GMO industry, told me via email that the groups concerns about genetically engineered food-crops extend to Penn State's new Crispr mushroom.

"What are the unknowns about CRISPR generally, and in particular, in its application in this mushroom?" he asked. "Regulators should determine whether there are off-target effects. Consumers have the right to know what’s in our food."


In Europe, however, where anti-GMO advocates have strongly opposed Crispr, the director of the Swiss Research Institute of Organic Agriculture recently came out in favor of Crispr, telling a German newspaper that it's different from the traditional genetic-engineering technologies and would alleviate many of the concerns groups like his have with older gene-editing techniques.

In academic labs, many other crops have already been engineered with Crispr, including soybeans, rice, and potatoes. The agricultural technology firm Dupont is testing using Crispr to make drought-resistant corn. It told the MIT Technology Review that it plans to start selling Crispr-engineered seeds by the end of this decade.


Yang told Science News that he would also seek approval from the Food and Drug Administration before releasing the crop to market as a precaution, even though he is not technically required to do so. For now, the Crispr mushroom remains relegated to the lab.

But, as Voytas points out, the promise of Crispr crops requires rethinking what we consider a GMO, or perhaps how we consider different techniques of genetic engineering in different situations. Is a tomato that's been spliced with a fish really the same thing as a mushroom that's just had a teeny bit of plastic surgery? Probably not.