Genetic crops are feared, but traditional breeding presents risks of its own

People opposed to genetically engineered foods call them Frankenfoods. Tinkering with nature, that label implies, can produce dangerous monsters. <br><br>But many scientists note that farmers have tinkered

Tuesday, April 11th 2000, 12:00 am

By: News On 6

People opposed to genetically engineered foods call them Frankenfoods. Tinkering with nature, that label implies, can produce dangerous monsters.

But many scientists note that farmers have tinkered with nature for thousands of years to try to improve crops. Genetic engineering, these scientists say, adds more precision to the age-old crop breeding method of trial and error.

Emotions run high in this latest fight over food.

Activists have damaged laboratories and test fields. Scientists who think genetically engineered crops could allay food shortages in undeveloped nations are frustrated that their work may be stifled before it reaches its full potential.

Last week, a report issued by the National Academy of Sciences concluded that there is no evidence that genetically engineered plants on the market today pose health risks to people, and aren't any more likely to harm the environment than conventionally bred crops. The report also urged the federal regulatory agencies that oversee genetically engineered plants to do a better job of coordinating their work.

The new report is not likely to end the debate - even before it was issued, an environmental group had scheduled a news conference to question the panel's objectivity and the report's conclusions.

"Genetic engineering is a new major step in life sciences," said Marshall Martin, an agricultural economist at Purdue University in West Lafayette, Ind. "It's normal for people to question whether this is safe."

But lost in the debate, food and crop specialists note, is that many of the concerns voiced over genetically engineered crops also apply to new crops bred through conventional means. And traditionally bred crops are not reviewed by any federal agencies before hitting the market.

New crops, no matter how they are bred, have the potential for unacceptable levels of toxins, said Fred Gould, a professor of entomology at North Carolina State University and a member of the committee that compiled last week's report. Conventionally bred as well as genetically engineered crops have the potential to spread their disease resistance to nearby weeds, or to serve as breeding grounds for insects that can outwit the crops' defenses.

"We've seen problems in conventionally bred plants," Dr. Gould said, although such problems are very rare.

Using conventional techniques, breeders try to mix the best traits from different varieties of plants. A breed of potato with resistance to a parasitic worm, for instance, might be mated with another breed that produces particularly high yields. A breeder would then check the offspring from that mating to find one that had inherited both the parasite resistance and the high yield. In this way, new genetic combinations, never before seen in nature, are created.

Genetic engineering, scientists argue, is similar. Scientists create new genetic varieties not by mating two breeds of plants, but by inserting particular genetic traits using advanced laboratory techniques. The new genetic trait can come from the same plant species, or from a completely different organism, such as a bacterium. Several seed companies, for instance, have inserted a bacterial gene - one that produces a chemical that is toxic to caterpillars - into crops such as potato and corn. Caterpillars that eat the crops die.

One fear with genetically engineered plants has been that pollen containing the bacterial gene might fall on a nearby weed, producing a "superweed" that is also resistant to the caterpillars, letting the weed flourish. Also, the insects may evolve resistance to the toxin, making them unstoppable.

Dr. Gould said the same concerns could apply to crops bred by conventional means.

Although conventionally bred crops won't contain bacterial genes, they can contain natural plant genes that confer resistance. Those traits could also be transferred to nearby weeds, he said. And insects, in theory, could also evolve resistance to the plants' natural defenses.

"Some naturally bred plants have a single resistance gene," Dr. Gould said. "It could happen just as easily as with genetically engineered plants."

In addition to environmental concerns, critics have suggested that foods from genetically engineered plants could pose health hazards to people.

In response to public concerns, the U.S. Food and Drug Administration instituted a policy in 1992 in which manufacturers could voluntarily consult with the FDA to ensure both genetically engineered plants and new varieties bred through conventional means were safe. FDA scientist Jeannette Glew said the agency believes that data on all genetically engineered foods have been submitted through this procedure.

Twenty-five percent of corn acres, and more than 50 percent of soy acres, were seeded with genetically engineered varieties this year, according to the U.S. Department of Agriculture.

Although the FDA review procedure was designed to ensure safety of both conventionally bred and genetically engineered plants, data only on genetically engineered plants have been submitted.
Ms. Glew stressed that there is no reason to fear crops bred through conventional means.

"Most of these foods have been raised for hundreds of years," she said. "They don't raise many concerns."

But, she noted, more may be known about genetically engineered crops than some conventionally bred ones.

No federal system exists to test conventionally bred crops before they appear on supermarket shelves. That responsibility has traditionally been in the hands of breeders, said Robert Plaisted, a professor of plant breeding at Cornell University in Ithaca, N.Y.

For instance, Dr. Plaisted and his colleagues have been developing a strain of potato from a parent that had unacceptable levels of alkaloids, chemicals that can be toxic. The potato hasn't been released, Dr. Plaisted said, because it's still not ready for industrial use. If it is released, he said, a description of its alkaloid content will be published in a scientific journal on potatoes.

In theory, however, he said, anyone can put a potato with high levels of alkaloids on the market. The FDA has the authority only to take problem foods off the market, but not to check them before they go on the market.

While genetic engineering of foods is under high scrutiny, the new report on safety released last week noted that conventional breeding has changed considerably in recent years, and also deserves more research.

Still, Dr. Gould stressed that there is no reason to be concerned about conventionally bred plants.

"Vegetables are good for you," he said. "What we're saying is we could make them better if we did more research."

As for genetically engineered foods, Dr. Gould said, they should be tested because there are an infinite number of possible new genetic combinations that can be created.

"As we advance, we could do a lot of things and build plants in a lot of ways," he said. "We have computer hackers; I hope we don't have gene hackers. We're just saying be careful."

And Dr. Plaisted noted that genetic engineering will not replace conventional breeding, which can combine many beneficial genes at once in new ways.

"It's a wonderful tool to add a single trait to a variety," he said. "But [genetic engineers] . . . are dependent on the continuous release of new varieties grown in conventional ways."