When federal regulators declared the AquAdvantage salmon fit to eat last fall, it became the world’s first genetically engineered animal to be approved for human consumption. Eric Hallerman, professor of fish conservation in Virginia Tech’s College of Natural Resources and Environment, advised the U.S. Food and Drug Administration (FDA) on the environmental issues surrounding transgenic Atlantic salmon as part of the agency’s investigation.
“The FDA is respected globally,” said Hallerman, who is an affiliate of Virginia Tech’s Fralin Life Science Institute. “Now that the U.S. has approved an animal for food, other countries might follow.”
To create the AquAdvantage salmon, scientists at AquaBounty Technologies in Maynard, Massachusetts, transferred a growth-hormone gene from the largest species of Pacific salmon, the Chinook, and a genetic on-off switch from a different species, the ocean pout, that triggers expression of the gene year-round. Conventional Atlantic salmon produce growth hormone only in the summer, but the AquAdvantage fish responds to the growth hormone and eats heavily all year. Although the mature AquAdvantage salmon grows no bigger than its wild cousins, it reaches full size twice as fast.
AquaBounty asked Hallerman — who is not otherwise affiliated with the company — to lead research on the fish’s environmental impact. Hallerman had pushed for a better framework for risk assessment and management in genetic engineering since the late 1980s. As a postdoctoral associate at the University of Minnesota, he published several papers with his supervisor Anne Kapuscinski, now a professor of environmental studies at Dartmouth, on the ecological ramifications of farming transgenic fish. In the early 1990s, Hallerman helped develop the performance standards the U.S. Department of Agriculture uses to evaluate the safety of aquatic genetic engineering projects.
Hallerman and his co-investigators discovered that AquAdvantage fish could potentially breed in the wild, passing down their engineered genes. So AquaBounty developed a system of redundant safeguards to confine their salmon. The company grows only sterile females and raises them in aboveground tanks in Panama. If these cold-water fish escaped, they would probably die in the warm, muddy rivers downstream from the facility, 4,000 miles from their spawning grounds along the North Atlantic.
The FDA invited Hallerman to present his findings in September 2010. “At the hearing, I was asked flat-out, ‘Would you approve this?’ I said yes,” Hallerman recalled. “That recommendation sat around for five years.”
At that time, FDA representatives told reporters that the agency would issue its environmental assessment, one of the final steps in a scientific review that AquaBounty had initiated in 1995, within weeks. The document wasn’t released until December 2012, two days after an article in Slate magazine accused the White House of blocking its publication to avoid political backlash. Genetically modified foods face fierce opposition from some consumer advocates and environmental groups, and Greenpeace, Friends of the Earth, and Consumers Union all lobbied to postpone the decision. The FDA finally approved the salmon grown in AquaBounty’s existing facilities in November 2015. If the company wants to expand production, it must re-apply for approval to sell fish from its new operations.
In his first year on the faculty at Virginia Tech, Hallerman argued before Congress for a better system for regulating animal biotechnology. More than 25 years later, the U.S. still lacks legislation that specifically addresses transgenic animals. Instead, agencies have based oversight of genetically modified organisms on extension of existing laws. Genetically engineered animals that produce food fall under the animal drug provisions of the federal Food, Drug, and Cosmetic Act.
“If Congress had created a rational framework for regulating genetic engineering — one you can amend when necessary, and that gives the agencies some leeway — that would have been great,” Hallerman said. “But the government is still overseeing animals as a drug, which is ridiculous.”
The unpredictable regulatory process may threaten the whole field of animal biotechnology. Faced with the time, expense, and political clout required to win approval, many researchers have moved their labs to countries with more favorable policies, such as Brazil, or dropped projects altogether.
“AquaBounty spent millions of dollars to go through the regulatory pathway, and that has precluded other neat inventions from going through to completion,” Hallerman said. “Scientists saw the prospect of endless regulation and decided, ‘I can’t tie up my tanks for years. I have limited capacity. I have to do experiments that can get published and bring grants.’”
The next animal to be approved, Hallerman predicts, will be a mosquito. With field testing recently approved by the FDA, a modified Aedes aegypti mosquito designed by the British firm Oxitec can reduce wild populations of the species, which transmits dengue fever and the Zika virus. Scientists implanted a gene that prevents Aedes aegypti’s cells from functioning without the antibiotic tetracycline. When modified males mate with wild females, their offspring inherit the lethal gene and die before reaching adulthood. Unlike chemical fogging, the transgenic mosquito doesn’t harm other insect species or natural habitats.
“You’re getting rid of an invasive mosquito and using genetic engineering to relieve human suffering,” Hallerman said. “That’s pretty compelling.”