Even on a high, dry plateau in central Oregon, it’s hard not to find a riot of grass. Farmers grow Kentucky bluegrass for the seed, and lining irrigation canals are wild varieties of rabbit’s foot and water bent, along with stubby lawn grasses that, grown thick, would make an excellent putting green.
And recently, a new variety has joined the scene: feral, genetically engineered bentgrass.
Early this past decade, the Oregon Department of Agriculture conducted a field trial just north of the town of Madras, planting 400 acres of bentgrass engineered by the Scotts Co. to resist the popular weedkiller Roundup. Scotts hoped the bentgrass, if approved, would be a financial bonanza, allowing golf courses to douse their fairways with herbicide, mimicking what has become standard practice at farms growing Roundup Ready corn and soybean countrywide.
|AquaBounty’s bioengineered Atlantic salmon, above, grows twice as fast as its similarly aged conventional counterpart. The growth is stimulated by a chinook salmon growth gene, activated by a DNA “switch” from the eel-like ocean pout. Courtesy of AquaBounty.
Problems quickly became apparent. Unlike domesticated crops, which farmers must reseed each year and carefully tend, the bentgrass could thrive and persist in the wild. Only one major planting occurred, in 2002; the fields were fumigated after a year. But over the next half decade, the grass spread far across the plateau, its pollen scattered in the breeze, said Carol Mallory-Smith, head of Oregon State University’s weed science program, who studied the migration.
While the grass is environmentally benign, it has proved impossible to eradicate.
“If we went out there right now,” Mallory-Smith said, “[it’s] still out there.”
DNA splicing is nothing new. Nearly all of the cotton, corn and soy grown in the United States carry bacterial genes for pest or weedkiller resistance. Few companies, however, have sought to sell bioengineered plants and animals that can survive and even thrive without human tending. Firms feared a backlash should their creations escape, wary they could spread irreversibly like Scotts’ bentgrass.
That resistance is creeping away.
Most prominently, AquaBounty Technologies is nearing approval of its fast-growing salmon that, if cleared by the Food and Drug Administration, would be the first genetically engineered animal on supermarket shelves (Greenwire, Sept. 21). Unlike the engineered cows and pigs that will follow it, AquaBounty’s salmon remains a fundamentally wild creature, albeit with a massive appetite. And it is just the beginning of genetic engineering’s spread to the wilderness.
Scientists have developed several other fast-growing fish, including trout and carp, and traits like improved nutrition are coming. One biotech firm backed by International Paper Co., ArborGen LLC, has trials of cold-tolerant eucalyptus trees scattered across the Southeast. And biofuel startups are developing biotech prairie grasses that grow fast and full in degraded soil, sparing food prices while surviving for years with little human intervention.
Another decade in the future, the changes get more complex. Companies are developing genetically engineered algae to consume carbon dioxide and sweat oil products, but barring a massive binge in greenhouse construction, the algae, designed to grow aggressively, will be cultivated in open ponds (ClimateWire, July 22). And while they may not be developed in wild plants, firms are close to growing commercial pharmaceutical components in farm crops.
This bioengineering surge is forcing regulators to encounter ecological challenges far knottier than in the past: how to avoid a repeat of the Oregon grass escape; how to judge, in the lab, the environmental risk posed by wild escapees and their genes; and, most fundamentally, how and whether to stop these plants and animals from pursuing nature’s ultimate imperative — reproduction — in the wild.
“These are wilder species that are difficult to study,” said Allison Snow, an ecologist at Ohio State University. The first generation of domesticated crops were hard enough, she said, but “it’s more challenging when you have long-lived trees and grasses, and when you have fish and algae. … As we get into more and more species with more and more traits, there are going to be many more challenges.”
Just like in nature, not all genetically engineered life is created equal. Off the farm, several modified plants and animals, their traits obviously benign, are widely sold. Glowing zebrafish armed with jellyfish genes swim in U.S. pet stores. Hawaii’s papaya trees are engineered to resist a devastating virus. Similarly, one effort to restore the American chestnut tree depends on splicing in genes to resist blight.
But then there are traits, like cold resistance or speedy growth, that could allow escaped organisms to beat out their wild counterparts in the struggle for food, sunlight and sex. These tweaks could counter the conventional wisdom among scientists that genetic engineering cripples life’s ability to survive in the wild. And companies like ArborGen and Aquabounty have realized that, facing these fears, they must find a way to make their creations as sterile as mules.
ArborGen has been growing freeze-tolerant, sterile eucalyptus at a trial in Sebring, Fla., for several years. Earlier this year, the Agriculture Department allowed most of the company's experimental plantations across the Southeast to reach flowering age. Courtesy of ArborGen.
“There are ways we could build in mechanisms to prevent and inhibit gene flow into the environment,” Kausch said. “How severe does it need to be? I don’t know. You could build in redundancies and fail-safes if necessary.”
Scientists have received little general guidance from regulatory agencies on what will be required for their wild creations. Until a few years ago, the U.S. Department of Agriculture tended to view all proposed plants in the same light, scientists say, and the agency still has not indicated whether it will require bioengineered trees or grasses to be sterile, and, if so, how strictly they define sterility.
“This is a challenge that has not been addressed,” Kausch said. If the government wants zero tolerance, imposing rules that no pollen can escape, “then draw that line in the sand and let the technology people develop what’s necessary,” he said.
In many ways, FDA and USDA are still improving their ability to evaluate environmental risks
from next-generation biotech. FDA has quietly launched a pilot program to overhaul its animal biotech program, hiring new scientists for the task. And this year USDA reorganized its biotech division, creating a dedicated team to assess environmental risks, requesting $5.8 million for the upgrade.
FDA has pushed AquaBounty to add several layers of containment to its proposed salmon, including sterility controls. Most scientists agree these efforts are thorough. But the agency, in pushing these provisions, has so far allowed the company to ignore analyzing what would happen to the waters around its facilities in Prince Edward Island and Panama should fertile salmon escape.
“FDA and the company, AquaBounty, are presumptive,” said Yonathan Zohar, head of the University of Maryland’s marine biotechnology department. “They make assumptions. They say, because it’s Prince Edward Island, the eggs will not be able to survive. Because it’s Panama, the fish will not be able to survive. … I would like this to be done experimentally.”
Unlike bioengineered trees or grasses, which would have to be grown in open fields to achieve any sort of commercial viability, companies tinkering with fish have several confinement advantages. The fish can be grown at inland facilities, as AquaBounty has proposed, which will spare oceans the pollution and escape problems caused by typical pen-based fish farms. And the salmon embryos, after conception, can be shocked into sterility with high efficiency.
But like plant biology, the techniques used to induce fish sterility are never 100 percent. Life is tricky, and often it finds a way to survive, said Tillmann Benfey, a fish biologist at the University of New Brunswick and one of the world’s leading experts on aquaculture controls.
“In biology, nothing is perfect, especially when trying to get around sexual maturation,” Benfey said. “It’s really what evolution is all about.”
‘Fish are … very plastic’
The government knows that sterility controls are a looming issue. Six years ago, the National Academy of Sciences released a study on bioconfinement science. Most of the technologies being developed were in their infancy, many mere ideas, it said. And while the research has rolled on since then, bioconfinement remains an untested field, with all degrees of uncertainty and hypothetical methods.
The best-known techniques for imposing sterility come not from manipulating genes, but entire chromosomes, the protein-DNA complexes that hold genes. Most animals carry two sets, one from each parent. If, by biological chance, a mammal ends up with three full chromosome sets, it is unlikely to be born. Mammals are rigid like that.
Fish, however, are a different story.
“Fish are unusual vertebrates in that they’re very plastic,” said John Buchanan, AquaBounty’s scientific director. For example, female fish flooded in testosterone will develop as males, though they only carry female genes, a process AquaBounty uses to produce all-female stocks. And fish that carry three chromosome sets — called triploids — are able to function much like more stress-prone varieties of their normal peers, except in one way: They can’t reproduce.
No one is quite sure exactly how the fish survive with three chromosome sets, or how it arrests sexual development.
“The mechanism of sterility has never been studied very well,” said Serge Doroshov, a fish biology professor at the University of California, Davis. But it works, with particular success in salmon; carp, though, can reproduce despite an added chromosomal burden.
Sapphire Energy is one of several startups tapping algae to produce biofuels indistinguishable from oil. The company's trial ponds in New Mexico contain only conventional algae, but the firm plans to cultivate bioengineered algae in the future. Courtesy of Sapphire Energy.
Over the years, aquaculture specialists have discovered ways to use shocks of high pressure to arrest the development of fish eggs just after fertilization, before they have shed their mother’s extra chromosome. It is commonly used on trout stocks for sport fishing and has become a well-developed, if not foolproof, technique, said Benfey, whose work on triploids guided AquaBounty.
For its FDA application, AquaBounty has promised more than 95 percent of its bioengineered eggs will be triploid. It is a high rate, probably the best that can be done with current technology in a commercial setting, Benfey said. But it also means each shipment will also carry fertile females.
“That’s the story in biology,” Benfey said. “Nothing is 100 percent.”
Benfey’s phrase is a familiar refrain. The inability for one system to ever promise full containment means that, if regulators have any hope of controlling wild bioengineered organisms, multiple systems will need to be in place, said Ohio State’s Snow, who was an author on the National Academy report.
“If you’re going to even come close, you’re going to have a lot of redundant mechanisms,” Snow said.
Bioengineered salmon are actually in a promising place because of the need for redundancy, according to AquaBounty’s Buchanan. The firm will sell only females to inland fish farms with strict physical separation from natural waters. The company does not have to worry about the wind, about pollination.
“We’re in a better place than crops,” Buchanan said.