Mushrooms that don’t brown. Wheat that fights off disease. Tomatoes with a longer growing season.
All of these crops are made possible by a gene-editing technology called Crispr-cas9. But now its future has been clouded by the European Union’s top court.
This week, the court ruled that gene-edited crops are genetically modified organisms, and therefore must comply with the tough regulations that apply to plants made with genes from other species.
Many scientists responded to the decision with dismay, predicting that countries in the developing world would follow Europe’s lead, blocking useful gene-edited crops from reaching farms and marketplaces. The ruling may also curtail exports from the United States, which has taken a more lenient view of gene-edited foods.
“You’re not just affecting Europe, you’re affecting the world with this decision,” said Matthew Willmann, the director of the Plant Transformation Facility at Cornell University.
But the ruling also raises a more fundamental question: What does it actually mean for a crop to be genetically modified?
In its decision, the European Union court exempted crops produced through older methods of altering DNA, saying they were not genetically modified organisms. That assertion left many scientists scratching their heads.
“I don’t know why they are doing that,” said Jennifer Kuzma, an expert in genetic engineering at North Carolina State University. “I was thinking, ‘Do they have the right science advice?’”
Since the agricultural revolution 10,000 years ago, all crop breeding has come down to altering the genetic composition of plants. For centuries, farmers selected certain plants to breed, or crossed varieties, hoping to pass useful traits to future generations.
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In the early 20th century, scientists discovered genes and invented new ways to breed crops. Two lines of corn, for example, could be melded into hybrid plants that were superior to either parent.
By the 1920s, researchers realized that they didn’t have to content themselves with amplifying the genetic variations that already existed in plants. They could create new mutations.
To do so, they fired X-rays at plants or used chemicals that disrupted plant DNA. Mutagenesis, as this method came to be known, introduced random mutations into plants.
Scientists inspected the mutants to find those that were improvements. Thousands of plant breeds in use today, from strawberries to barley, are the product of mutagenesis.
In the 1970s, microbiologists figured out how to insert genes from humans and other species into bacteria. Plant scientists later used recombinant DNA, as the technology came to be known, to develop methods for inserting genes into plants to improve their growth.
Some varieties of corn, for example, received a gene from bacteria that allowed the crops to produce an insect-killing toxin. These came to be known as genetically modified crops, and they sparked a storm of controversy.
Environmental groups such as Greenpeace and Friends of the Earth raised concerns that genetically modified crops posed unpredictable dangers.
The plants might escape farmers’ fields and spread through wild ecosystems, for instance, perhaps hybridizing with wild plants and introducing their genes into new species.
Environmental groups also raised the possibility that genetically modified crops could harm human health. Genetically modified crops not only produce proteins from their own genes, but from the genes of other species, as well.
On opposite sides of the Atlantic, the conflict has played out in very different ways.
In the United States, the National Academy of Sciences has found no evidence to confirm that gene-edited crops are any more dangerous than conventionally bred ones.
While the government has put in place a number of regulations governing genetically modified crops, the industry has boomed. Over 185 million acres of these crops were planted in the United States in 2017.
In Europe, by contrast, concerns about genetically modified organisms led the European Union to issue a directive in 2001. From the early stages of research to the marketplace, these products would have to pass a series of tests for environmental risks and human safety.
But the directive made it clear that crops made through older forms of mutagenesis were not genetically modified organisms because they were “conventional” and had “a long safety record.”
The result of the directive has been that Europe grows almost no genetically modified crops. In 2017, only 325,000 acres were planted across the continent.
In the years after the E.U.’s directive came out, science advanced beyond recombinant DNA. Rather than inserting a gene from another species, researchers learned to snip out piece of a plant’s DNA, or even rewrite short stretches of genetic material.
Instead of inserting foreign genes, scientists were able to edit a plant’s own DNA in new ways. They could create crops that make more, or fewer, proteins from their own genes, gaining advantageous traits.
When scientists first started experimenting with gene-editing on crops, the European Union offered no clear guidance. In 2015, a French agricultural union and allies such as Friends of the Earth went to court to have gene-edited crops labeled as genetically modified organisms — and regulated as such.
And now the court has agreed. In a statement, the court said gene-edited crops were GMOs “within the meaning of the G.M.O. Directive.”
Dana Perls, the senior food and agriculture campaigner at Friends of the Earth, praised the court for recognizing gene-editing as genetic modification. “We need to call it what it is,” she said.
Ms. Perls said that Crispr and other new methods for tinkering with plant DNA raise concerns about safety, just as recombinant DNA did.
“Gene-editing technologies have unintended consequences,” she said.
Ms. Perls pointed to some scientific journal articles that describe how Crispr and other forms of gene-editing can miss their targets, accidentally altering other stretches of DNA in an organism.
But one of the authors of those papers, Jeffrey D. Wolt, a professor of agronomy and toxicology at Iowa State University, was dismayed by the E.U. court ruling.
“It all boils down to legal interpretations of the directive rather than the weight of the science,” he said.
Dr. Wolt said that it’s important to distinguish Crispr research on plants and the use of gene editing to develop new medical treatments.
There are many opportunities in plant experiments to screen out unwanted mutations. As a result, the chances of unexpected mutations in gene-edited plants are falling to low levels.
Dr. Wolt said that there wasn’t a strong scientific reason to consider gene-edited plants to be G.M.O.s while exempting crops created in the old way, with X-rays and chemicals producing many random mutations at once. “It’s hairsplitting,” he said.
The United States is continuing to veer from Europe. In March, the Department of Agriculture announced that it was not planning to regulate gene-edited crops as it does crops with foreign genes inserted with recombinant DNA.
As a result, Crispr-edited crops like mushrooms are expected to move quickly into the American marketplace. But these crops may be barred from import into Europe.
Strictly speaking, however, the United States stance also is contradictory. Crops created with recombinant DNA, are said to be genetically modified organisms, because genes have been inserted into their DNA.
Yet tinkering with a plant’s DNA with Crispr is apparently not genetic modification, because these crops “are indistinguishable from those developed through traditional breeding methods,” according to a U.S.D.A. statement issued in March.
Dr. Wolt said that the only way to escape these contradictions would be for government regulators to stop focusing on mutagenesis, recombinant DNA, Crispr and other methods for making new crops. “It’s the products we should be concerned with,” he said.
“As soon as we solve this problem favorably or unfavorably for Crispr, there’s going to be a new technology that comes along and we’re going to have the same problem again.”