Gene-Edited Pork Could Be Coming Soon to Your Dinner Plate

Pork from genetically modified pigs could end up on dinner plates around the world within the next few years.

A company in the United Kingdom is editing the genes of pigs used for commercial pork production to make them resistant to a deadly virus estimated to cost global farmers $2.7 billion a year, reports New Scientist’s Michael Le Page. If approved, the pigs could become the first genetically modified animals to be bred for widespread meat consumption.

The company, Genus, hopes the U.S. Food and Drug Administration will greenlight its virus-resistant pigs by the end of this year or early in 2025. It is also seeking approval in other countries that import U.S. pork, including China, Colombia and Mexico.

The virus is called porcine reproductive and respiratory syndrome (PRRS), also known as blue ear disease. First recognized in the U.S. in 1987, PRRS causes no symptoms in some pigs, but it can lead to pneumonia in piglets and reproductive failure in adult females. The virus also weakens pigs’ immune systems and makes them more vulnerable to bacterial infections.

In the U.S. alone, PRRS costs farmers $560 million each year, according to the World Organization for Animal Health. It’s “the most economically significant disease to affect U.S. swine production since the eradication of classical swine fever,” according to Iowa State University. Vaccines are available, but they’re not 100 percent effective.

The virus targets part of a gene known as CD163. Scientists at Genus are using the gene-editing technology CRISPR to modify CD163 in the embryos of four common types of commercial pigs. They then transfer the modified embryos into female pigs and continue breeding the female’s gene-edited offspring. In the end, this produces a lineage of pigs that have both copies of their CD163 gene disabled.

They described their methods—which have produced a healthy “founder population” of virus-resistant pigs—in a new paper published this month in the CRISPR Journal.

Their work is “not just a nice study in a nice model,” says Rodolphe Barrangou, who serves as the journal’s editor-in-chief and was not involved in the research, to Science’s Jon Cohen. “It’s actually doing it in the real world.”

If all goes to plan, Genus hopes to begin selling semen from the genetically modified pigs within the coming years. The first generation of pigs that results from the semen won’t be resistant to the virus—only the sperm, not the egg, will have the modified CD163 gene—so farmers will need to breed the offspring to produce fully resistant pigs, a process that could take a few years.

The company will also give farmers tests that can show whether the ensuing pigs have the required gene edit to make them immune to the virus.

“Nowhere on the planet is it going to be a light switch, where suddenly everybody’s got the edited pigs,” says Clint Nesbitt, Genus’ global director of regulatory and external affairs, to Science. “It’s going to be much more like a dimmer switch.”

Additionally, to earn FDA approval, Genus must show the altered gene is safe, able to be passed down stably through generations and effective at providing immunity. The agency is already several years into this process for the CRISPR-edited pigs.

Some organizations, like the National Pig Association in the U.K., are supportive of the plan to use gene-edited pigs for commercial pork production, because it could mean the animals will endure less suffering caused by the virus. Likewise, “I think by and large the farmers are quite excited to have it, because this is a fairly devastating disease,” Nesbitt tells New Scientist.

But some animal welfare organizations say gene-editing is a slippery slope that could lead to more inhumane treatment of farm animals. They fear that if pigs are resistant to disease, they could end up being kept “in even more crowded, stressful conditions than at present,” said Peter Stevenson, chief policy advisor at the nonprofit Compassion in World Farming, in an October 2022 statement.

“We fear gene editing will entrench factory farming and take us further down the road of treating animals as machines that can be fine-tuned for ever faster growth and higher yields despite the severe repercussions for animal welfare,” he added.

Animal welfare groups in the U.S. have made similar arguments. They say that by keeping animals in crowded conditions that allow pathogens to spread and evolve, commercial livestock producers are responsible for the rise of deadly diseases like PRRS in the first place.

“Rather than developing genetically engineered animals who can survive the horrific cruelties of factory farming, agribusiness should focus instead on addressing the conditions that create these diseases,” says Gene Baur, president and co-founder of the American nonprofit Farm Sanctuary, to Popular Science’s Andrew Paul.

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Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.