U.S. panel releases consensus on genetically engineered crops

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Once again, U.S. expert panel says genetically engineered crops are safe to eat

Almost 2 years ago, a group of 20 scientists began hashing out a consensus on the risks and benefits of genetically engineered (GE) crops. Since the launch of their study, sponsored by the National Academies of Science, Engineering, and Medicine, the public debate around the safety of genetically modified organisms (GMOs) and whether to label them has continued to rage. But behind the scenes, some things have changed. Agricultural markets are now bracing for an explosion of new plants designed using the precise gene-editing technology CRISPR, and regulators in both the United States and the European Union are struggling with how to assess their safety.

The panel’s report, released today, is a hefty literature review that tackles mainstay questions in the well-worn GMO debate. Are these plants safe to eat? How do they affect the environment? Do they drive herbicide-resistance in weeds or pesticide-resistance in insects? But it also weighs in on a more immediate conundrum for federal agencies: what to do with gene-edited plants that won’t always fit the technical definition of a regulated GE crop.

The authors picked through hundreds of research papers to make generalizations about GE varieties already in commercial production: There is “reasonable evidence that animals were not harmed by eating food derived from GE crops,” and epidemiological data shows no increase in cancer or any other health problems as a result of these crops entering into our food supply. Pest-resistant crops that poison insects thanks to a gene from the soil bacterium Bacillus thuringiensis (Bt) generally allow farmers to use less pesticide. Farmers can manage the risk of those pests evolving resistance by using crops with high enough levels of the toxin and planting non-Bt “refuges” nearby. Crops designed to be resistant to the herbicide glyphosate, meanwhile, can lead to heavy reliance on the chemical, and spawn resistant weeds that “present a major agronomic problem.” The panel urges more research on strategies to delay weed resistance.

Few researchers will be surprised at those conclusions, says Todd Kuiken, who leads the Synthetic Biology Project at the Woodrow Wilson International Center for Scholars, a think tank in Washington, D.C., but public skepticism of GE crops runs deep. “Whether the academy kind of putting their seal of approval on that impacts the discussion, I don’t know.”

Regulatory muddle

The report saves the issue of regulation for its final chapter. Many countries—including the United States, whose framework for reviewing new biotechnology products was drafted in 1986—didn’t envision modern technologies when they legally defined genetic engineering. The first generation of GE crops used a bacterium to ferry genes from one organism into another. But CRISPR can knockout or precisely edit DNA sequences without leaving behind any foreign DNA. In fact, the DNA of a gene-edited crop could end up looking nearly identical to that of a conventionally bred variety. Last month, the U.S. Department of Agriculture (USDA) deemed two CRISPR-edited crops, a mushroom that resists browning and a high-yield variety of waxy corn, to be exempt from its review process because neither contained genetic material from species considered to be “plant pests.”

Critics of those decisions argue that small genetic changes can still have big effects on the characteristics of a plant, and that gene-edited crops have slipped through the cracks without proper safety testing. Others argue that the precision of CRISPR limits environmental and health risks by making fewer unintended tweaks to a plant’s genome, and that subjecting them to a full regulatory review is needlessly costly and time consuming for their producers.

Last summer, the White House announced it would revamp the legal framework for evaluating biotechnology products across USDA, the Food and Drug Administration, and the Environmental Protection Agency (EPA). The European Commission, meanwhile, is also mulling whether plants without foreign DNA count as genetically modified.

Like several National Academies reviews before it, the new study condemned regulatory approaches that classify products based on the technology used to create them. “The National Academy has been saying since 1987 that it should be the product, not the process,” says Fred Gould, an applied evolutionary biologist at North Carolina State University in Raleigh, and chair of the new report. “But the problem up until now is … how do you decide which products need more examination than others?”

There, the report makes a new suggestion: Regulators should ask for a full analysis of a plant’s composition—using modern “-omics” tools such as genome sequencing and analysis of the proteins and small molecules in a sample—to determine when a full safety review is necessary. The authors propose that crops containing different genes, producing a different set of proteins, or carrying out different metabolic reactions than conventionally bred varieties should trigger regulatory review if those differences have potential health or environmental impacts. And if a trait is so new that there’s no conventional counterpart to compare it to … just go ahead and regulate it, they conclude.

The approach is reasonable, Kuiken says, but it’s not clear how to implement it. “How close does it have to be to the counterpart before you have to do a full review?”

Gould acknowledges that the report’s recommendation is a tall order, but “if USDA and EPA don’t use -omics techniques and they deregulate a crop, and then somebody in a research lab just takes a look at the transcriptome and finds a difference, you’re in trouble.” Deciding exactly which kinds of genetic or metabolic changes represent a risk will be left to regulatory agencies. “We just give principles,” Gould adds. “We’re not in the trenches with them.”

If those entrenched regulators crave more guidance, they’re in luck. The National Academies just launched yet another study, due out by the end of this year, to predict the next decade of biotechnology products and describe the scientific tools needed to regulate them.

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