Biotechnology: DNA On The Dinner Table 

Geoffrey Cowley / NEWSWEEK Jan01

It was just the sort of mishap that anti-biotech activists are always warning us about. In late September, tests revealed that genetically altered corn—a variety intended for livestock, not for human consumption—had found its way into millions of Kraft taco shells.

The company recalled the tortillas, federal agencies reviewed the incident and the media spent weeks covering it. Yet when American consumers were asked about the scare, no one seemed worried about sprouting extra arms. The main concern was that restricting the new corn to farm animals might push up the price of a taco. “If no one’s getting sick, and no one’s dead,” one happy nosher told The New York Times, “I’m OK with it.”

Europeans were less sanguine last spring when Aventis CropScience disclosed that some genetically modified rapeseed had got mixed with conventional seed in shipments that reached several countries. U.S. regulators had deemed the seeds safe for release into the environment, and American fields were full of them. But on learning of the mix-up, the governments of France, Germany, Luxembourg, Sweden and the United Kingdom all ordered the resulting crops dug up and destroyed (Britain alone cleared more than 11,000 acres). Even then, citizens worried that mutant plants might have pollinated neighboring fields. The problem, according to French President Jacques Chirac’s office, is that “the majority of genetically modified products are too new for us to know exactly what the risks might eventually be.”

DEEP SUSPICIONS

 Biotechnology is transforming the world’s food supply, or at least America’s. U.S. growers had already planted 76 million acres of genetically modified (GM) crops as of 1999, and the number is rising fast. Experts predict that U.S. farms will harbor more GM crops than conventional ones by the year 2020, and that virtually all nonwild plants will be genetically modified by the end of the century. But as Europeans settle into the new century, they remain deeply suspicious of the whole trend. “Food security” has become a near obsession in France, ranking second only to unemployment as a public concern. And though British Prime Minister Tony Blair has actively promoted biotech farming, British growers are loath to produce food for which there is no local market. Is such stiff resistance warranted? Does GM farming pose real risks to health or the environment? No one denies that it could have downsides as well as advantages. But the evidence suggests that “Frankenfood” is less dangerous than most people realize. As University of North Carolina biologist C. Neal Stewart puts it, the fears have “escalated beyond scientific rationality.”

Farmers have spent centuries crossbreeding crops—i.e., altering their DNA—to make them produce food that is heartier or tastier or more abundant. Modern genetic science simply speeds that process. Because they pinpoint the genes governing particular traits, bioengineers work with far greater precision than traditional plant breeders. And because genes are all made of the same stuff, useful ones can often be transferred between unrelated species. Isolate the gene that lets a soil-dwelling microbe make a natural pesticide—toxic to insects but harmless to people and other animals—and you can transfer it into food crops, enabling them to fight off bugs. Outfit a rice plant with the gene that lets dandelions produce vitamin A, and you may get a more nutritious grain. This form of agriculture is less than two decades old, but it has already spawned more than a dozen new crops. Most of today’s GM plants are indistinguishable from conventional ones, except that they’re more resilient and less disruptive to the environment. But innovations now in the works could directly affect health and nutrition worldwide.

Why bother injecting foreign genes into plants that are already perfectly edible? The original motivation was simply to help them survive. Insects and infections claim roughly a fourth of the world’s crops each year, and the toxic chemicals we throw at them pose major threats to soil and water quality. Scientists have known for decades that a microbe called Bacillus thuringiensis, or Bt, makes proteins that kill crop-eating insects without harming plants, animals or people. Unfortunately, one of the qualities that makes Bt toxins environmentally friendly also limits their usefulness: when sprayed on crops, they’re quickly broken down by the sun and washed away by rain. One of biotechnology’s first triumphs was to isolate Bt’s pesticide genes and transfer them into cotton plants, making the plants’ own tissues poisonous to pests. Bt-enhanced cotton seeds reached the market in 1996, cutting pesticide use by some 2 million pounds the following year. Bioengineers have since spliced Bt genes into corn, soy and potato plants—and none of the altered crops is known to have harmed anyone’s health.

ARMED PRODUCE

Researchers have made similar inroads against crop-killing viruses and bacteria, but they’ve used a different technique. Instead of poisoning the parasites, they endow crops with one or more of the parasites’ genes, in effect immunizing them. The first sign this might work came in 1986, when microbiologist Roger Beachy outfitted tomato plants with a gene from the tobacco mosaic virus. The virus is normally lethal to tomatoes, but Beachy’s GM plants were unfazed by it. Since then, researchers have used the same principle to arm squash, potato, cantaloupe and papaya against various pathogens. Other researchers have created crops that tolerate herbicides, enabling farmers to spray mild weedkillers during the growing season instead of sterilizing their fields between plantings. Still others are developing crops that will withstand drought or extreme temperatures.

These innovations have been felt mainly by growers, but the next generation of GM crops could directly affect consumers both rich and poor. With luck, nutritionally enhanced rice will soon provide much-needed iron and vitamin A to underfed children in Africa, Asia and Latin America. New strains of cassava, a staple throughout much of the developing world, will harbor fewer of the cyanide-producing cells that make the root such an impractical food source. In the developed world, farm-raised salmon will grow to seven pounds in 18 months—half the time a conventional fish requires. GM potatoes will absorb less oil when they’re fried, and the oil itself will be richer in healthful monounsaturated fatty acids. Only 24 percent of the fat in a conventional soybean is mono-unsaturated, but DuPont has raised the proportion to 80 percent in a bean recently approved for U.S. marketing. Researchers are also racing to grow foods that will vaccinate kids against various infectious diseases.

No one denies that all this gene shuffling could have risks as well as benefits, but researchers have yet to identify extreme or unmanageable hazards. One common concern is that proteins capable of triggering allergic reactions will show up in foods that don’t normally contain them. This isn’t a small issue when you consider that one person in 50 (5 million in the United States alone) suffers from food allergies. “If a gene is moved from a common allergen like a peanut into something like a tomato, where no one expects it to be, that’s a potential threat,” says Dr. Hugh Sampson of New York’s Mount Sinai School of Medicine. During the mid-1990s, a company called Pioneer Hi-Bred spliced a gene from Brazil nuts into soybeans to improve the soy’s nutritional value. But when scientists placed the soy’s new proteins in blood samples from people with nut allergies, they saw clear reactions and the company pulled the product from development. Fortunately, 90 percent of all food allergies are caused by a handful of proteins found in nuts, wheat, milk, eggs and seafood. In the unlikely event that the U.S. Food and Drug Administration approved a GM food containing known allergens, the agency would demand label warnings. Though unknown allergens could conceivably slip through the system, researchers would spot many of them with laboratory tests before they reached the market.

ECOLOGICALLY FRIENDLY?

Consumer safety aside, some skeptics worry that GM crops will prove less ecologically friendly than they seem. One concern is that insects will develop resistance to Bt’s natural pesticides as we spread them through the environment. Growers can slow that process by maintaining non-Bt fields, which keep susceptible insects in the mating game, but nothing can stop it completely. A second worry is that weeds will gain the survival advantages of GM crops. Suppose, for example, that the wind carries pollen from an herbicide-resistant sunflower to a weedy relative. The weed’s offspring might acquire the gene for herbicide resistance, making them (and their progeny) as resilient as the crop. “We’re discovering that crops and weeds don’t have strong barriers between them,” says Ohio State University biologist Allison Snow. ”[Cross-pollination] is far more common than we thought.” Still another possible risk is that crops designed to repel pests will prove toxic to other species as well. In one lab study, researchers found that monarch butterfly larvae suffered increased mortality when forced to eat large amounts of pollen from Bt corn. But studies performed under more realistic conditions haven’t shown that effect.

All these issues will need to be followed closely as we modify plants for our own ends. “This is new technology with which we have had limited experience,” says Gordon Conway, president of the Rockefeller Foundation and a strong proponent of the new agriculture. “While we gain experience, we need to move cautiously.” But moving cautiously is different from standing still. The revolution has already begun. And though we may encounter resistant pests, weedy hybrids, sick butterflies and allergic consumers before it’s over, it’s worth remembering that none of those problems is unique to biotech farming. GM crops are not fundamentally different from conventional ones. They simply exhibit more of the qualities that make conventional crops valuable. GM food may not reach many European tables next year. But as the promise of the new technology is realized, its allure will be harder and harder to resist.

With Erika Check in New York, Scott Johnson in Paris and Shehnaz Suterwalla in London.