Picturing DNA
Chapter 6:
Are We What We Eat?

Introduction

Chapter 1

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 7

Epilogue

Eating is serious business for all animals, and humans are no exception. Not only do we depend on food to fuel our bodies and maintain strength, but we associate everything we eat with our first source of nourishment, our mother, and the love and warmth that was part of the package. From the association of food with nurture, we have made an art form of the need to eat, so the possibility that someone has tampered with our food stirs bedrock emotions, from fear to outrage to fury.

In the past, ordinary people risked eating bad meat or rotting vegetables because they had no choice. Emperors, with their limitless powers, used tasters, human guinea pigs who would succumb to any poisons before they reached the royal mouth.

Today's royal mouths are seldom better served than the mouths of ordinary Americans. Consumers in the United States and Europe live in a kind of cornucopia undreamed in the past. No longer are menus limited by season or geography to a single crop, be it wheat or corn, rye, barley or rice, as were the tables of our ancestors-and the bowls of many people even today. Yet fear of food poisoning lingers in our memory, and outbreaks of hysteria over contamination, whether exaggerated in the case of alar on our apples, or real in the case of Mad Cow disease, have brought angry protestors into the streets.

Yet the grains that our ancestors ate in the nineteenth century and the rices eaten today are not the same grains and rice people ate thousands of years ago. Over the eons, groups of peoples in both the new world and the old enhanced the size and flavor of their grains by selecting which seeds to fertilize with which mates, and which plants to graft together. One of the first successes in the domestication of grains was the deliberate loss of seed dispersal. Farmers needed ripe seeds to stay on the plant so they could be harvested. The mutations that they chose occurred naturally but are counterproductive for wild plants. In Darwinian terms, these mutations would have been nonadaptive in the wild, but for farmers they were exactly the right thing.

Retracing the history of corn from modern Kansas back to its ancestral home in Central America reveals a silent record of extraordinary ingenuity by peoples who lived thousands of years ago. The process of artificially selecting and improving crops proceeded slowly in the Old World and the New until the agricultural revolution of the eighteenth and nineteenth centuries. By then landowners looked to their crops as more than a way to feed themselves and their dependents; they sought to improve the quality and quantity of what they could sell for cash. Within less than a century they were remarkably successful in improving grain, as well as fruits and vegetables, through careful selection. By domesticating plants, they were speeding up what might have occurred naturally in the field over a long period of time.

By the early twentieth century, fewer and fewer farmers in Europe and North America were providing food for larger numbers of people, many of whom, born and raised in cities, had never seen a field or a cow. As farmers mechanized production, another series of innovations revolutionized the way those crops got to the table. Except for crude salting and drying-to produce the "jerky" and "hard tack" that were the staples of sailors, immigrants and explorers-there had been few innovations in extending the shelf lives of foods. The development of tin cans and freezer cars in the nineteenth century and frozen foods, rapid transportation and freeze-dried foods in the twentieth completed the break between the menu and the calendar.

The demands of a rapidly doubling human population for more food were met initially by developing new varieties of grain, fruits and vegetables. The sprinkling of pollen on the stamen of plants, as farmers had been doing since antiquity, was described scientifically in the late-seventeenth century. But the last decades of the twentieth century saw a partnership between biologists and some giant agribusinesses to improve and increase crops by genetically engineering, or as the British say, genetically modifying, plants.

These innovators had two markets in mind. They looked at the tables of the rich and saw a demand for new and exotic foods. They looked at the rapidly expanding populations in poor countries and saw a market for genetically engineered foods, medicines and vaccines. They saw what appeared to be a win-win situation. With a little help from their laboratories, leaders of agribusiness reasoned that they could satisfy the demands of the rich for gourmet food and also feed the hungry multitudes and even perhaps even cure the chronically ill, all the while securing a healthy profit. They could do well by doing good.

In the last five years of the twentieth century, with little interference from any U.S. regulatory agency, these companies planted over 20 million acres of genetically engineered crops and marketed about thirty thousand products made from the harvests. In their enthusiasm, they did not foresee the critics calling their new products Frankenfoods-unnatural life forms wrought in laboratories by wicked scientists-or the angry picketeers disrupting trade meetings on the streets of London, Seattle, Washington and Washington, DC.

Leaders of agribusiness did not seem to understand. "But people have been interfering with foods in nature as long as there have been people," they pleaded.

The protesters responded, "But nature does not snip a strip of genes from the DNA of a fish and splice it into the DNA of a tomato or strawberry to make them frost-resistant."

The protesters were right. Little in agricultural history foreshadowed the creation of transgenic plants. The new crops created by the deliberate transfer of genes from animals to plants, or from one plant to another, do not occur in nature. The promise of new kinds of foods, larger crops free from blights and food-bearing medicines is tantalizing, which why these companies made their energetic leap into genetically engineered food. But it is also terrifying, which is why so many environmentalists, biologists and ordinary people with a distrust of science and big business, into vocal opposition.

These latter saw genetically engineered foods as an even worse case of poisoning than the use of DDT, alar and other chemical pesticides that had alarmed previous generations. For too many decades, farmers had routinely sprayed their crops, leaving not only a residue of insecticides on fruits and vegetables, but also polluted ground water and soil.

The popularity of foods grown without chemical insecticides increased through the 1990s. If every farmer farmed organically, it was suggested, everyone could relax in a world free from both insecticides and genetic manipulation. But that is not an economically viable way to produce vast quantities of food for a worldwide market, nor is organic food necessarily healthier than other foods. Neither growers nor consumers could afford the losses caused by insects and blights. Agribusiness offered, instead, genetically engineered crops as a way of eliminating the need for chemical pesticides. They were not prepared for the resentments and skepticism of a public that over almost a century had built up a not unreasonable distrust of the two-headed beast that is science.

Promising benefits, science seemed to always have delivered a delayed downside: radiation burns from X-rays; fatal reactions in the 1940s to sulfa, the first "miracle" drug; cancer from living in buildings where asbestos had been installed as a means of fire prevention. The possibility that recombinant DNA could produce monster genes that would escape and destroy the world has already emerged as a common fear in the 1970s.

By the mid-1990s, however, the U.S. Department of Agriculture had established guidelines that allowed large agribusinesses like Monsanto to plant fields of genetically engineered varieties of corn, tomatoes, soybeans and squash. These crops were also monitored by the Food and Drug Administration and, in some cases, by the Environmental Protection Agency. Yet this oversight is without much enforcement, and there are no requirements that genetically engineered crops, or products made from them, carry labels indicating their origins. Individual nations in the European Community, however, have legislated that all genetically modified foods must be labeled. European consumers have since voted with their pocketbooks not to buy them, and their governments have been refusing to import American foods with genetic modifications.

A handful of multinational companies control the fields, laboratories, and distribution in modern food production, especially in the United States. But their corporate vision is in direct conflict with the emotional way most people perceive food. The companies looked to genetic engineering as an opportunity "to create a genuine science of nutrition." However, their actions, Monsanto's in particular, enraged a spectrum of opponents, including economists and political scientists as well as environmentalists and conservative biologists.

Companies like Monsanto use two techniques used to insert foreign genes into a plant's DNA. The first, developed in the 1970s, is the technique still used to alter animal DNA. A gene is attached to a bacterium that enters the plant cell's DNA. In some instances, the new gene is attached to a virus, which acts as vector-a biological term used here to describe an organism that carries another substance with it into the plant's DNA. A more common approach today is to coat the surface of microscopic metal balls, often gold, with the new DNA and blast it into the plant cells. The plant sloughs off the gold, and its cells merge the new DNA with their own genetic material.

The technology seems foolproof, but there are some plant geneticists who fear that pollen from newly engineered plants could somehow escape. The gene that make the plants resistant to certain insect pest might then spread to weeds that are related, producing a superweed that would force development of a new weed killer. This has not happened so far, according to most biologists, because it is extremely difficult to transfer a gene even in the laboratory, and nature sees to it that most exchanges don't work. But that does not mean the exercise is risk-free.

A second concern is that genetically engineered plants could kill off the larvae of insects that we welcome in our ecosystem. The only way to prevent this is to be especially careful in field trials. Although the risk is very small, everything possible has to be done to protect the environment. The apparent failure of these safeguards seemed to have been realized in the fall of 1999. An entomologist from Cornell University published a short report in which he blamed the death of eggs of the already fragile and much beloved monarch butterfly on the pollen from corn that had been genetically engineered to include Bacillus thuringiensus (Bt) in its DNA. The experiment took place in a laboratory, and was not repeated in an open field, and has never occurred in nature. Yet the monarch butterfly's population continues to diminish. The habitat in Mexico where they spend the winter is vanishing and many environmentalists and entomologists believe this may account for the phenomenon. Others still maintain that the monarchs' difficulties result from contact with genetically-engineered corn.

For decades Bt, a soil-dwelling bacterium that produces a toxin deadly to crop-destroying worms but is harmless to mammals, was sprayed on corn and other crops and hailed by organic farmers, including the anti-DDT activist Rachel Carson, as a nontoxic alternative to chemical insecticides that can linger both in the soil and on the plant. But Bt is destroyed by sunlight and washes away easily, so it was not always successful. To make it more effective on corn crops, Monsanto had spliced Bt into corn DNA.

In the past, when Bt was sprayed onto plants in the field indiscriminately, it had sometimes killed butterflies and ladybugs; in a controlled experiment in the laboratory, 44 percent of the butterfly larvae that ate milkweed leaves dusted with Bt pollen died, just as they did in the field. But when the Bt was in the plant itself, it killed a much smaller percentage of insects, only those that ate the plant. Other studies have shown that in the cornfield, the concentration of pollen diminished noticeably only a few yards away from the edge. They also noted that corn pollination is usually over before the arrival of those great clouds of monarch butterflies arrived.

A third fear voiced by environmentalists is that if Bt is used long enough and on vast enough acreage, its efficacy of Bt will be squandered as Bt-resistant pests evolve. However the story may end, the plight of the monarch butterfly has become a major battle cry in the struggle against the creation and marketing of genetically engineered foods. For all the hue and cry against Bt, it is seldom mentioned that this is not an insecticide but rather a bacterium harmless to mammals, and that it is offered as an alternative to chemicals that are poisonous to animals and whose residue on food is probably unhealthy for people as well.

A fourth issue is the threat of infusing foods with allergens that could harm an allergic person. A potential disaster was prevented in 1995 when a company inserted the genes from a brazil nut into a soybean to increase the levels of amino acids in a soy-based animal feed. The soy contained an allergen can be deadly to people who cannot tolerate Brazil nuts, and who would have had no warning if they had eaten an apparently harmless cake prepared with the genetically-engineered soy. In this instance, when the company found that the blood of its laboratory workers tested positive for Brazil-nut allergen, they kept the modified soy off the market.

Q & A with Dr. Eric Lander

Q.Do you see any difference in the potential threat to human health between eating a genetically engineered pig and eating genetically engineered corn?

Lander: I have no idea. Are you asking if it's possible to conceive of genetic modifications [to food] that would cause harm to human health?

Q: Right.

Lander: Sure. It's possible to conceive of such things.

Q: Like what kinds of things?

Lander: Well, put in a peanut toxin, something that can be lethal to some people.

Q: Yes.

Lander: It's possible. I could imagine creating genetically modified things the same way I can imagine serving a cake that had nuts in it when you didn't tell them it had nuts in it.

Q: All right. So you don't actually see much difference between what's going on with geniitcally modified animals as with genetically modified horticulture. I think mostly hormones to make the animals mature quickly.

Lander: Sure. And there's this question that was raised about whether or not the fish growth hormones would be bioactive in humans.

Q: Right.

Lander: I don't know. You've got to test it. Suppose you were putting in a hormone that was bioactive in humans. Well, then you might have to worry about it.

Q: How would you find out?

Lander: About what?

Q: If it's bioactive in humans.

Lander: Usually for these hormones you know from human studies. Typically one good way is to find out whether the human hormone is bioactive in the other organism, because if it's cross-reactive in that direction, it's usually cross-reactive in the other.

Q: All right. So it's not a complicated thing to work out.

Lander: You can also do imaging cell lines. There are a lot of things you can do. It's not that hard to do some testing like this.

Q: So, we'd like to know what they've done, right?

Lander: Exactly. Basically, you can't say as a blanket statement that any genetic modification is safe. But you can say that a very large number of genetic modifications that people have been doing up till now don't seem to be likely to cause much apparent harm. And they should be subjected to the appropriate tests.

Q: And there are appropriate tests that we know about already?

Lander: In most cases, yes.

Defenders of genetically engineered soy respond that the odds of someone actually succumbing to such a product are very small, and the benefits large. Some plant biologists, in fact, see allergens as one of the areas in which they can make a great contribution. Now that molecular biologists are beginning to understand the identity of proteins that are allergens, they can explore ways of engineering them so they do not produce reactions in people. They note that there are still deaths each year from reactions to such common drugs as aspirin and penicillin, which nonetheless remain on the market. It is a question, they say, of how many people are helped and how many harmed. But there is a difference in these cases; people who are allergic to aspirin or penicillin usually know it, and take pains to avoid the products. Transgenic foods, however, are not labeled in most parts of the United States, and buyers cannot take preventive steps.

Yet another issue raised by opponents of genetically engineered foods is their fear that the viruses used as vectors in the splicing process will make consumers ill with the viral disease. Viruses can be dangerous because they carry disease into a cell and then reproduce wildly, destroying healthy cells. Viruses that have been defanged-that is, robbed of their talent for wild replication-become an excellent delivery system for bringing new DNA to a cell. Aware of the dark potential of viruses, biologists have engineered those used as vectors to be replication-deficient. They cannot form and spread new viruses.

The opponents also raise the issue of the antibiotics that are attached as markers in the transfer of DNA from one animal to another, and have in the past been used by some plant geneticists to track the success of plant DNA transfers. Might these antibiotics move into the body of the person who eats the food, thus causing the person to build up resistance to a medicine he or she may one day need? Biologists discount this possibility, pointing out that when we eat corn, for instance, we don't absorb the corn's genes into our cells. We absorb some nourishment, and the rest passes out of our systems. One scientist pointed out: "We don't become limes or lemons when we eat limes or lemons."

Monsanto was successfully engineering new kinds of crops when it grew sensitive to the possibility that genetically engineered seeds might cross-pollinate and spread to other vegetation. To avoid the possibility, Monsanto patented a process in 1998 that triggered a toxic protein in the plant that sterilizes its seeds. This seemed a clever solution to the potential problem of runaway pollen, but the reality of selling this product to non-industrial agricultural societies where farmers routinely saved seed from one season to plant in the next goes against traditional agricultural practice.

One of Monsanto's opponents, the Rural Advancement Foundation International, called these "terminator genes" because they self-destruct, forcing farmers back to Monsanto year after year to buy fresh seed. Monsanto had been accustomed to selling seeds to farmers who depended on hybrid plants, whose seeds have to be purchased annually. The company's adventures with terminator seeds is an instance of monumentally poor judgment. Monsanto abandoned the gene before they ever had a chance to see if it was really a good idea because they had so outraged public opinion by introducing it in a part of the world where it was socially and economically repugnant.

An economist in the Poverty Research Unit at the University of Sussex told Michael Specter of The New Yorker that "electricity is a fantastic invention, but if the first two products had been the electric chair and the cow prod, I doubt that most consumers would have seen the point." The really advantageous qualities of genetically engineered foods have been swamped in the press by descriptions of the terminator technology and economic practices that ignored the plight of third-world farmers. The British economist was suggesting that the egregious missteps of Monsanto and some of its agri-biotech partners had eclipsed the real progress these same companies have made adapting agriculture to feed and cure millions of people who are too poor to worry about food allergies.

In Kenya, for example, where the sweet potato is a food staple, Monsanto helped the national Agricultural Research Institute create a sweet potato with genes to protect it against common viruses that destroy entire crops. Plant biologists at Purdue University are working on genes that allow some sweet potato plants to tolerate drought conditions. A Tuskegee University professor has developed another sweet potato with high protein levels that he hopes to distribute to farmers in Vietnam with the help of the International Service for the Acquisition of Agri-Biotech Applications, a nonprofit group that is also working to develop papaya, a fruit rich in Vitamin A, that would be resistant to viruses. Help for citizens of Uganda may be coming from a new banana that is being engineered by plant biologists at Cornell University. The banana incorporates vaccines for Hepatitis B and diarrhea and can be fed to children in a country with little refrigeration, without which traditional vaccines cannot be distributed.

But perhaps the most impressive product of genetic engineering in agriculture is golden rice, so-called because the three genes introduced into its DNA lead to creation of beta-carotene. Beta-carotene, which gives carrots their characteristic color, is a compound that arises in the genetically engineered rice and that results from the complicated interaction between three genes-in this case, two from daffodils and one from a bacterium. Our bodies convert beta-carotene into vitamin A, the lack of which causes blindness in the poorest people in that third of the world's population that depends on rice as its only staple food. The medical miracle that would follow the widespread introduction of golden rice could become the first great public-health accomplishment of the twenty-first century.

Agriculture is not the only area of controversy in the debate over genetic engineering of food. There is considerable agitation against the production of milk from cows that have been injected with bovine somatotropin, a natural hormone mass produced by genetic engineering. Bovine somatotropin allows cows to give many times the amount of milk they would otherwise produce. The use of this hormone has angered dairy farmers and animal rights activists as well as opponents of genetic engineering. The farmers see an excess of milk and milk products already on the market, and feel that the increased production is a way of pushing small dairy farmers out of business. Defenders of animal rights plead that the cows are visibly uncomfortable because their udders weigh them down; worse still, the udders are so heavy with milk that the pressure produces severe udder infections. The opponents of genetic engineering point out that these infections are treated with antibiotics, and that these antibiotics get into the milk, providing an unnecessary dose of antibiotics for milk drinkers.

The economic and ethical arguments against using bovine somatotropin are valid and worth discussion. However, the scientific argument about the negative impact of this milk on human health is misdirected because the necessity of treating these animals with antibiotics results not from genetic engineering but rather from bad animal husbandry.

Soon, not only bovine growth hormone, but genetically engineered cows, chickens, goats, sheep, pigs and fish will arrive in the supermarket. The first will probably be salmon, a farm-raised variety engineered with genes that promote growth so rapid that they are market-ready in half the time it takes normal salmon. The problems here mirror the problems with genetically engineered crops: there is probably little danger to the consumer, but unknown dangers to the environment. Farmed fish, for instance, have been known to escape into open sea from the nets that keep them isolated. At sea, where females tend to mate with the bigger males, the engineered fish could replace the normal fish through ordinary sexual reproduction.

As with agricultural crops, the production of genetically engineered fish and food animals is overseen by the Food and Drug Administration, the Department of Agriculture and the Environmental Protection Agency. But these agencies work with a mix of guidelines, which are voluntary, and regulations, which are not. Moreover, none of these agencies has enough staff to supervise those areas in which they have authority to act, and so they tend to avoid responsibility when they do not see a clear mandate.

The coalition of economists, ethicists, environmentalists and scientists opposed to genetically engineering foods have good reasons to be suspicious of giant, often global, corporations that have often overlooked the interests of consumers and struggling farmers in their search for profits. But the arrogant polices of these corporations does not mean that the genetic engineering of crops is wrong. These technologies, used judiciously, have increased the production of corn, soybeans and beets, foods that are helping to feed an increasing global population. The economic and political opposition to these technologies has economic and political solutions.

The scientific opposition deserves a different kind of attention. The question of risk is extremely important. Nothing is risk-free, of course, but the degree of risk and possible dangers have to be weighed in the light of the benefits. The threat of superweeds caused by unpredictable wind-blown pollen is small, but must be taken into account. The threat of serious allergic reactions to unlabeled genetically engineered foods is real and frightening. These are among the issues that have drawn crowds of protestors to America's streets.

The highhandedness of companies that rushed to plant millions of acres of genetically engineered foods, which was then sent to food processors and marketed without any indication of the food's contents, is already beginning to threaten the economic health of those companies. Americans are demanding labels, and some states are passing their own laws mandating identifying genetically engineered foods. At the same time, the foreign market for many U.S. foods has been cut off, especially in Europe, where public demonstrations against "GM" foods are everywhere. The European food giants Nestle and Unilever have stopped using all products containing genetically engineered ingredients, which means most American produce, not because they believe there is anything wrong with the produce, but because they do not want to face boycotts by powerful consumer groups.

After separating economic and social issues from the biomedical and technological implications of transgenic agriculture, there remains the problem of the loss of variation in crops. This has been addressed by banking old seeds when new varieties gain popularity. Seed banks are not a new idea, and there are such banks throughout the world. But it is questionable if there are enough banked seeds of any variety that could come to the rescue should there be a new plant disease like the potato blight that ravaged Ireland in the nineteenth century.

Whether transgenic foods are innocuous or not, no one should have to eat food that is unacceptable to them. Just as it would be reprehensible to pass off cookies made with sugar as sugar-free to unsuspecting diabetes, it is wrong to pass off genetically engineered foods as "natural" to those opposed to them.

Genetically engineered foods are not directly connected to the map of the Human Genome. But the techniques that have been developed as part of the sequencing process-the snipping and splicing of fragments of DNA from one living organism to another-are the same techniques whether the DNA is in crops or in medical genetics. In an effort that parallels the mapping of the human genome, biologists have begun mapping and sequencing plants. The first food plant, rice, is near completion. Of the flowering plants, Arabidopsis will probably be mapped first.

The revelations emerging from the study of plant genetics are manifold. Because plants are different from animals, but similar enough to accept animal genes into their own DNA, vaccines can be grown in plants that until recently have been grown in chickens, with greater assurance that the vaccine will be pure and not contaminated by a poultry virus. Equally important is the opportunity that maps of plant genomes will offer biologists who are interested in the way genes work. These scientists will soon be able to observe the logic of genetic communication within an organism that is not animal and so does not carry the intellectual burden of animal evolution.

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Picturing DNA by Bettyann Holtzmann Kevles & Marilyn Nissenson
Copyright © 2000 Bettyann Holtzmann Kevles & Marilyn Nissenson
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