The first gene-edited chickens are scheduled to hatch at the Roslin Institute at The University of Edinburgh in Scotland. The designer birds have been modified to resist flu, which spreads rapidly among CAFO (concentrated animal feeding operation) birds and has the potential to be transmitted to humans.
"If we could prevent influenza virus crossing from wild birds into chickens, we would stop the next pandemic at source," Wendy Barclay, a virologist at Imperial College London, said in a news release.1 The simplest way to stop the widespread transmission of bird flu would be to change the way chickens are raised, putting them outdoors on pasture as opposed to crowded in disease-ridden CAFOs.
But researchers discovered in 2016 that the ANP32 gene in chickens codes for a protein that flu viruses depend on,2 and cells without the gene were impervious to flu. Since then, they've been on a mission to change the gene in live chickens, and now it appears they've succeeded.
Gene-Edited Chickens Created
In order to create the transgenic chickens, scientists used the gene-editing technology known as CRISPR, or Clustered Regularly Interspaced Short Palindromic Repeat. Unlike genetically engineered (GE) foods, which may have genes from other species inserted, gene editing involves altering an organism's DNA.
They targeted part of the ANP32 gene in order to create the flu-resistant chickens. "We have identified the smallest change that will stop the virus in its tracks," Barclay said.3 Already, however, they're anticipating that the public may be less than enthusiastic about gene-edited chickens on the dinner table.
People eat food from farmed animals that have been altered by decades of traditional breeding," Barclay told Reuters. "But they might be nervous about eating gene edited food."4 Indeed, just as is the case with genetically modified organisms (GMOs), there remain many unknowns about gene editing as it pertains to human health and the environment.
Further, foods produced via gene-editing are not subject to regulation by the U.S. Department of Agriculture (USDA) or other regulatory agencies — although an advisory board recommended gene-edited foods could not be labeled organic.5
In fact, in March 2018, the USDA released a statement noting that it would not regulate CRISPR-edited crops, stating, "With this approach, USDA seeks to allow innovation when there is no risk present."6
Gene editing, with its loose regulation, accessibility and quick results, has been called the next "food revolution,"7 at least for plant foods, but it's unclear whether the same will hold true for animals. In the U.S., it's been proposed that gene-edited foods do not need to be labeled, either, but the European Union ruled that they should be regulated the same as GMOs.
Gene Editing Causes Side Effects in Animals
Gene-editing technologies are relatively new, but they're moving ahead at a feverish pace. With the innovation, however, have come a few setbacks that should, at least, raise a few red flags.
Researchers have used CRISPR-Cas9 and other gene-editing technologies to create cows that can tolerate warmer temperatures (so they can be raised in the tropics), goats with longer cashmere wool and rabbits and pigs with bigger, leaner muscles.
Serious side effects resulted, however, including enlarged tongues in the rabbits.8,9 Among pigs that were altered by deleting the myostatin (MSTN) gene, which limits muscle growth, the larger muscles came along with an extra vertebrate in 20 percent of the gene-edited animals.
"This phenomenon has never been reported in other MSTN-mutant animals," the researchers said,10and therein lies the problem. While scientists have made great strides in mapping out genomes of entire organisms, much remains unknown about the purpose of individual genes and how they interact with one another.
As such, making tweaks to genes, even those intended to be precise, often lead to surprising and unintended consequences.