THAT’S THE WAY THE COOKIE CRUMBLES (10 page)

Some of the flavor compounds in soft drinks are susceptible to oxidation. Manufacturers counter this effect by adding antioxidants such as ascorbic acid (vitamin C). Preservatives such as sodium or potassium benzoate ensure that microbes do not contaminate the drink, and approved artificial colors or caramel will increase eye appeal. In rare cases, some of these colors — particularly yellow #5 and yellow #6 — can cause allergic reactions.

Some people object to these additives, but there are far better reasons for not gorging on soft drinks than the fact that they may contain brominated vegetable oils or food dyes. We don’t need the extra sugar or caffeine. We do need the calcium in milk and the antioxidants in fruit juices, and soft drinks often displace these beverages from the diet. But we do not have to shun soft drinks totally. After all, they do add a little much-needed fun to our lives. Let’s just try not to have too much fun.

“Wow! Look at my DNA!” the exuberant little boy cried as he pulled the threadlike strands out of the test tube. Soon, other excited voices chimed in as about two dozen children and a sprinkling of adults began to play with their own genetic material. We were all seated around tables in a laboratory at the American Museum of Natural History in New York City, having been attracted by signs pointing towards “The Gene Scene.” Our experiment started with everyone swirling salt water in their mouths for thirty seconds or so to collect some of the cells that our cheeks continuously slough off. Our guide then asked us to spit the solution into a little cup (cries of “Yuck!” filled the room) and then transfer it to a test tube containing some detergent.

A couple of minutes of gentle shaking allowed the detergent to break down the cell membranes and liberate the DNA molecules, which formed a precipitate when a little alcohol was added. Next, we dipped a stirring rod into our test tubes and pulled out long filaments of DNA. As the session drew to a close, the guide asked the children present what they had learned. They provided some pretty good answers, but the one that really stuck in my mind came from the little boy who had cried out so enthusiastically when he first glimpsed his DNA. He said he’d learned that when he grew up he wanted to study biotechnology and become a genetic engineer. Quite a refreshing comment, given that so many people these days look warily on this area of science. We can generally attribute this reaction to confusion over what biotechnology is really about.

Simply put, biotechnology is the provision of useful products and services from biological processes. It does not necessarily involve scientists in white lab coats hovering over petri dishes. In fact, biotechnology goes back thousands of years. It probably began the first time someone used yeast to convert sugars and starches to alcohol. Yeast is a little living machine that takes in food and produces excrement. But don’t pooh-pooh that excrement. Many humans like it. It’s called alcohol. Molds are also neat little machines that produce a variety of by-products. When the ancient Egyptians applied moldy bread to wounds as a poultice, they were exploiting biotechnology. The mold probably churned out penicillin — which, of course, the ancients did not recognize as such — and it helped heal the wound.

No one was able to elucidate how these microbes convert raw materials into finished products until relatively recent times. The pivotal moment came in 1953, when Francis Crick and James Watson unraveled the molecular structure of DNA, the molecule that controls the inner workings of the living cell. The instructions for everything that a cell does are encoded in genes, which are specific fragments of DNA. Basically, genes tell the cell what proteins to produce. Proteins are needed as structural material and as enzymes, the catalysts that control all reactions in a cell. Once we clearly understood DNA’s role, it became obvious that if we could modify its structure, then we could alter the proteins it produced. By the 1970s, such manipulation — known as genetic engineering — had become a possibility. Scientists could transfer genes from one organism to another or even build them from fundamental components using the “Gene Machine” (invented by former McGill University chemistry professor Kelvin Ogilvie).

We are now beginning to see some of the practical results of this genetic tinkering. For example, cheese makers require an enzyme called chymosin to separate curds from whey. The traditional source is the stomach lining of calves, but we have now isolated the fragment of DNA, the gene, that tells the cell to produce this enzyme. We can incorporate it into the DNA of a yeast, which will then dutifully crank out chymosin. This has made cheese production more efficient, and it has also allowed for the manufacture of cheese that has no meat components — a factor that is desirable to those who conform to certain religious dietary restrictions, such as kashruth. Much more dramatic is the potential for treating people who suffer from specific immune system deficiencies due to a malfunctioning gene. Already, in one case, doctors have extracted a patient’s bone marrow, replaced the malfunctioning gene, and infused the marrow back into the bone. The patient now produces cells with normal genes.

These days, we use bacteria to which the human insulin gene has been transferred to crank out insulin for diabetics. Scientists have also engineered bacteria to produce TPA (tissue plasminogen activator), which has saved countless lives. Physicians commonly administer it to patients who have suffered heart attacks to dissolve blood clots. Unfortunately, bacterial fermentation cannot meet the need for TPA, and the drug costs thousands of dollars a gram. Researchers have recently succeeded in introducing the gene that codes for TPA into the DNA of a goat, with the result that the animal produces TPA that can be isolated from its milk. In this process, known as “pharming,” one goat can make as much TPA as a one-thousand-liter bioreactor.

Biotechnology may even prevent heart attacks from occurring in the first place. The little Italian hamlet of Limone Sur Grada has become famous because its inhabitants are free of heart disease, despite their high blood cholesterol levels. They have inherited a gene that codes for apolipoprotein A1, a special protein that scavenges cholesterol from the bloodstream. Injections of a genetically engineered form of this protein have dramatically reduced the clogging of coronary arteries in rabbits, a treatment that may eventually be viable for humans as well.

One day, perhaps, our young biotechnologist-to-be will work on this problem. But the day I encountered him, he was content to scrutinize a display about lysozyme, a natural milk enzyme with antimicrobial properties. We can use genetic engineering techniques to increase the levels of this enzyme in milk, thereby reducing udder infections and the need to dose infected animals with antibiotics. As the little guy wandered off, I noted that he stuffed his DNA sample into the back pocket of his jeans. Jeans that may have been dyed with indigo produced by recombinant DNA and made of cotton genetically engineered to repel insects without the need for pesticides. Of course, not everyone shares my optimistic view of biotechnology. And, certainly, there are some controversial issues involved. So read on and we’ll explore these.

The ancient Greeks did not have a good grasp of genetics. A giraffe, they thought, was a cross between a camel and a leopard, and an ostrich was the result of a camel mating with a sparrow. A tough task for the bird, one would think. Why did they hold such beliefs? Because, in the absence of facts, their imaginations took over. And they still prevail. A recent survey showed that a third of all Europeans believe that only genetically engineered tomatoes contain genes. Otherwise, the fruits are “gene-free,” and, presumably, “risk-free.”

Researchers undertake such surveys to gauge public reactions to genetically modified foods. It’s probably the hottest potato to crop up in the area of food safety since pasteurization was introduced in the early 1900s. Activists back then advised people to spurn the new process because it destroyed the nutritional qualities of the milk, and they even described the horrors that could arise from consuming “dead bacteria.” But the truth is that live bacteria were the ones they should have been worrying about. Of course, there are still holdouts who promote raw milk. They can have it.

Today’s bogeyman is not pasteurization but genetic modification. Just about everyone has an opinion on the subject, but much too often people base their opinions on hearsay and emotion rather than on scientific data. Consumers speak of “Frankenfoods,” and activists attack and destroy experimental fields planted with modified crops while at the same time they clamor for more research into the effects of such crops.

I am not going to suggest that there aren’t some contentious issues surrounding genetic modification. There are, just as there are with any new technology. And I’m certainly not going to say that scientists can absolutely guarantee that there are no pitfalls involved in the genetic modification of foods. Nobody can offer such a guarantee. Indeed, those who demand unqualified assurance about the safety of genetically modified foods are just plain naïve. We don’t make such demands concerning other aspects of life. We don’t refuse to fly unless someone assures us that the plane will not crash; that would be absurd. We fly because we know that the benefits outweigh the risks. This is how we have to look at genetically modified foods as well.

Before delving further into the issues, we must acquire some understanding of what genetically modified foods are all about.

Although the term “genetic modification” conjures up images of high-tech laboratories, humans have actually been modifying the genetic makeup of foods since time immemorial. If early farmers had not sprinkled pollen from one type of corn on another, we would still be looking at fifteen kernels per ear. If wheat had not cross-pollinated with some wild grasses, we’d have to contend with lower crop yields and more fungal damage. Without crossbreeding, we’d have no nectarines, seedless grapes, tangelos, or Mackintosh apples. We wouldn’t even have grapefruit. This fruit first appeared in the eighteenth century, a result of the long-term crossbreeding of various citrus fruits. In each of these cases, genes from different species intermingled to bring out new, desirable traits. But this kind of genetic manipulation takes a long time, and it can sometimes foster undesirable traits.

Then, in 1974, scientists made a breakthrough. For the first time, they isolated and copied genes — those little segments of DNA molecules, found in the nucleus of every cell, that direct an organism to carry out its myriad functions. In other words, they cloned them. This created the potential for inserting genes into the DNA of a target cell. Here the genes would be incorporated into the cell’s genetic machinery and direct the cell to carry out some desired function. The scope of possibilities seemed almost unlimited. We could now guide plants to synthesize the insecticidal proteins or enzymes critical for the formation of natural anticancer substances.

Technically, plant genetic engineering is a complex business. The most common method makes use of a soil bacterium called
agrobacterium tumefaciens
. This bacterium contains rings of DNA, called plasmids, which we can remove and open up using specific enzymes. We can now add a segment of DNA from another species — that is, a gene; next, using another set of enzymes, we incorporate it into the plasmid; finally, we reintroduce it into the bacterium. This, in turn, we place in a solution along with a leaf from the plant that is to receive the gene. Here the bacterium infects the plant and transfers DNA from the altered plasmid into the plant’s chromosomes. Chromosomes are the strands of DNA located in a cell’s nucleus that are responsible for an organism’s genetic makeup; they reproduce as a cell divides. The plant then grows with the new gene incorporated into its DNA, ready to express its desired trait.

This, then, is the technology that biotech companies are pursuing. And let’s understand that just because something is good for Monsanto, Novartis, AstraZeneca, or any other company involved in biotechnology, it isn’t necessarily bad for the public. But if you listen to the alarmists, you may form the impression that these companies are trying to foist poisons on us purely for the sake of profit. Naturally, there is a buck to be made. But profits come with the production of good and useful products. No company wants to undermine its existence by marketing dangerous substances. The industry has commissioned a great deal of research into genetic modification and its safety aspects. And we are seeing the practical benefits.

Genetic modification of crops to afford protection against certain insects is already well established.
Bacillus thuringiensis
is a natural soil bacterium that produces a protein, commonly referred to as Bt, which is toxic to many caterpillars. We can transfer the gene that codes for this protein into a plant cell’s nucleus, and the plant will then thrive, even in the face of an insect infestation. Growers need to use fewer insecticides. In the U.S., four out of every ten pounds of insecticides used go to protect cotton, but farmers are already reporting that they have reduced their insecticide use by several million pounds annually. Canadian farmers who grow canola engineered to be resistant to the herbicide glyphosate (Roundup) report reduced chemical use. Farmers also till less often, which means less water pollution and less erosion. In China, Bt cotton is a big success story; more than two million farmers cultivate it. Production costs have dropped by twenty-eight percent, and the farmers’ average annual income has increased. Use of toxic pesticides such as organophosphates has plummeted by eighty percent, and reported cases of pesticide poisoning among cotton farmers have decreased from twenty-two percent to five percent. Sounds good. So why are protesters dumping transgenic soybeans on the doorstep of Tony Blair, the British prime minister?

One of the concerns they raise is over insertion of a gene that makes a plant resistant to the antibiotic kanamycin. Scientists will sometimes incorporate this gene along with a set of desired genes as a marker to indicate whether they have successfully implanted the desired genes. If the plant is unaffected when placed in an antibiotic solution, then it is properly expressing the new genes. The question is whether these antibiotic-resistant genes are transferred to animals and to humans, decreasing the effectiveness of antibiotic drug treatments. (Actually, the antibiotics in question are not important for human use.)

Another worry is that pollen from genetically engineered plants may cross with wild plants, producing “superweeds.” This has not surfaced as a problem yet, but pollen from genetically modified canola has spread more extensively than we had predicted. Farmers in western Canada who had no intention of growing modified canola now find that their fields are contaminated with it. Insects may develop resistance to Bt protein, giving rise to “superinsects,” although experiments have shown that when we sow Bt-producing plants along with regular plants, we dramatically reduce such resistance. Of course, insects can develop resistance to any type of insecticide. Pollen from Bt corn may travel to other plants and produce unexpected effects. Cornell University researchers discovered in pilot studies that by sprinkling pollen from Bt corn onto the leaves of the milkweed plant they could kill the caterpillars of the Monarch butterfly, which dine exclusively on these leaves. But field trials have not corroborated these findings. Allergens may be inadvertently introduced. What are the consequences of introducing an antifreeze gene from the Arctic flounder into tomatoes to enhance frost tolerance? Will it present a problem for people with fish allergies if this technology is ever realized?

Many of the potential problems, such as the allergy issue, that are now being vocalized by opponents of genetic modification were, in fact, addressed long ago by the industry. Researchers have been testing for allergens in modified foods since the inception of the technology. In one case, the addition of a Brazil nut gene to soybeans in order to increase the quality of the protein in animal feed resulted in the transfer of an allergen. In other words, someone with a Brazil nut allergy could have reacted to eating the genetically modified soybeans. But researchers picked up the problem in routine testing, and the soybeans, which had only been destined for animal feed anyway, were never marketed.

This is quite a different approach from the one we take towards foods that have not been genetically modified. We don’t ban peanuts, or strawberries, or fish because some people are allergic to these foods. And these allergies are far more prevalent than the theoretical allergies to modified foods. Indeed, we may be able to modify peanuts genetically in order to eliminate the protein that is responsible for allergies.

Opponents of genetic modification suggest that we should be satisfied with the normal process of crossbreeding plants to produce improved varieties. But where is the guarantee that this procedure doesn’t introduce undesired chemicals? Appropriate crossbreeding can, for example, yield plants that are more resistant to insects. And why don’t insects attack these plants? Because they contain more natural toxins than other plants. Nobody knows the human consequences of eating these natural pesticides. Why are the activists not demanding that all hybrid plants — or, indeed, that all plant foods — be tested for natural toxins?

Let me allow for the possibility that genetically altered foods present an as-yet-unidentified risk. One can always conjure up some theoretical catastrophe. But let’s compare this to the very real benefits that genetic modification can offer. Combating malnutrition, for one. When people think of malnutrition, they usually think of starving children. But that is not the only kind of malnutrition out there. In fact, the most common kind of malnutrition in the world is iron deficiency. This can cause intellectual impairment, suppressed immunity, and complications in pregnancy. Millions suffer from iron-deficiency anemia. Most of them subsist on rice, a grain that contains very little iron, and the body cannot absorb the iron it does contain because of the presence of substances called phytates. These compounds bind iron in the digestive tract and substantially prevent it from being transported across the intestinal wall into the bloodstream.

Genetic modification has yielded a variety of rice that contains more iron. Scientists accomplished this by inserting a gene isolated from the French bean into the DNA of the rice. This particular gene codes for the synthesis of a protein called ferritin, which is an iron-storage protein. In other words, the new rice can take in more iron from the soil. Furthermore, scientists also added another gene — this time from a fungus — which codes for an enzyme that breaks down phytates, making iron more readily available.

Populations that subsist on rice also suffer from vitamin A deficiency. That’s because rice is very low in beta-carotene, the body’s precursor for vitamin A. Deficiency of this vitamin is a major cause of blindness in the developing world; estimates indicate that some 250 million children have vitamin A levels low enough to cause impaired vision. Lack of vitamin A also predisposes a person to various cancers and skin problems.

Researchers addressed this problem by introducing into rice four genes that code for the proteins that enhance beta-carotene synthesis: two from daffodils, and two from a bacterium. The rice they created was yellow, clearly demonstrating that it was now fortified with beta-carotene. Experiments are under way to cross the iron-rich rice with the beta-carotene-rich rice to produce a super-rice that will alleviate nutritional problems affecting billions of people.

We face many other fascinating possibilities. How about genetically modifying foods to contain higher levels of cancer-fighting compounds, such as sulphoraphane, found in broccoli? Or developing fresh fruits and vegetables with improved shelf lives? Or crops that will flourish in salty soil? What about tomatoes that not only taste better but also contain more anticarcinogenic lycopene? Seed oils with a healthier profile of fats are a possibility. So are crops that are more resistant to frost. We can use genetically modified potatoes to produce proteins that can serve as vaccines against human disease. All of these are real possibilities. Granted, we’re not likely to see these benefits tomorrow, or next week, or even next year. The Wright brothers’ first flight provides an appropriate analogy. The spectacle of their rickety airplane bouncing along for a couple of hundred meters was not very impressive, but anyone who saw it, and possessed a little imagination, realized that it was only a matter of time before the airplane would revolutionize travel. People had to witness it in action before they could accept it; then, over time, the details could be worked out. So it is with genetic modification.