Gus Stevenson

It has been more than 10,000 years since human beings have made the connection between putting a seed in the ground and plants that grow food. Since the discovery of agriculture, human beings have been trying to find ways of improving plants so that they can better meet our needs. The processes of crop improvement have come a long way. We are now able to genetically modify plants. This means that we are actually able to alter the genes of the plant to create a stronger, healthier, more resilient plant. But what kinds of crops are commonly involved in genetic modification, are they fit for human consumption, and what are the dangers of tampering with the delicate balance of nature?

Crop improvement is about as old as agriculture itself. In order for farmers to grow enough food for their families, tribes, and nations, they had to find new techniques to maintain and increase production. One way was the use of fertilizers. Fertilizers have long been used to feed rich nutrients to the plants (leRiche 32). Conversely, herbicides have been used to rid the ground of weeds that would strangle the plant's roots. Unfortunately, herbicides may also harm the plant itself. As many other creatures besides humans rely on plants for food, pesticides are now used to keep insects from munching on the year's harvest.

Methods of preserving and storing food were also an important part of maintaining the harvest. In many parts of the world, food was, and in some places still is, stored in woven baskets (leRiche 51). Insect damage is a major problem. In many parts of Asia and Africa, insects and rodents destroy one-third to one-half of the grain (leRiche 51). People have been using preservative methods, a necessity to keeping stored foods from rotting or being eaten by insects, for thousands of years (leRiche 52). The early Romans used ice and snow to preserve perishable foods (leRiche 51). Other peoples sliced apples and hung them to dry in the sun. Grapes, figs, apricots, and many other fruits were also dried to be preserved (leRiche 51). Mustard, now used as a condiment, was once used as a preservative (leRiche 52). However, the largest steps toward understanding inheritance, and eventually how to genetically engineer plants, didn't come until the mid-1800s, when an Austrian monk named Gregor Mendel conducted private experiments with pea plants (Genetic 6).

While Mendel was tending his garden, he began to notice something very strange. Some of is pea plants were green, while others were yellow. He began cross-breeding the plants, and found that some plants would become green, even if both plants were yellow, and vice versa (Genetic 6). He studied some 5,000 plants in this manner, and eventually deduced that hereditary information is stored in units, which are now called genes (Genetic 6). However, Mendel wasn't the first to cross-breed plants. For nearly 2,000 years, cultivators have been crossing two selected plants to produce offspring with the desired traits of both parents (Genetic 5). However, since they did not have any knowledge of inheritance or genetics, this process was hit or miss.

Mendel's work has become invaluable to the study of inheritance in plants, as well as all other creatures. Through Mendel's work, we have been able to discover the "building blocks" for almost everything on this planet. Each gene is a piece of information contained in what has come to be known as deoxyribonucleic acid, or DNA. DNA is a molecule that contains sugar, phosphate, and four bases: adenine, guanine, thymine, and cytosine; or A, G, T, and C (Genetic 15). The strands of DNA are translated by ribonucleic acid, and then use that information to build proteins (Genetic 15).

The science of genetics has come a long way since the time of Mendel. We are now able to actually take a single gene from one organism and implant it into the DNA sequence of another. This is accomplished through a process known as "gene-splicing." For example, a scientist can remove a gene from a fish, and place it into a tomato (Teitel 7). The genetic traits that are taken from one organism and inserted into another may include resilience to herbicides, disease, and pests; a yield of larger fruit, or a change of the color or height of the plant. In theory, vitamins, minerals, and even medicine not normally associated with that particular plant can be inserted into the plant's DNA.

Essentially, the theory behind gene-splicing is pretty straightforward. A gene from one organism is removed, isolated, and "pasted" into the DNA of another organism (Teitel 7). In practice, however, it is far from simple. The desired gene from the first organism must be located among the 5 million or so genes in the cell nucleus (Genetic 18). Then, the genetic engineer uses a restriction enzyme to isolate the gene (Genetic 18). This enzyme recognizes the specific gene and "snips" it out of the DNA sequence (Genetic 18).

Once isolated, the gene must be cloned and inserted into the host cell (Genetic 18). Both are accomplished using a vector to duplicate the gene and transport it into the plant genome (Genetic 21). Bacterium or viruses are commonly used as vectors (Teitel 8). Viruses are often used because they attack host cells and slip right into the cell’s DNA (Teitel 8). Genetic engineers attach a piece of DNA to the virus, then insert the vector into the new organism, so it can infect the cells of that organism, and thus deliver the new DNA fragment into the DNA of that organism (Teitel 8).

When bacteria is used, it is done by way of a plasmid--a tiny, circular piece of bacterial DNA (Genetic 19). The foreign gene is inserted into the plasmid, and as the plasmid replicates inside the bacterial cell, it copies the foreign gene along with its own gene allotment (Genetic 19). The gene is then removed from the bacteria cell and introduced into the plant cell. In order to distinguish normal cells from genetically engineered ones, scientists use antibiotic-resistant genes to mark the vectors. "The cells are then doused with antibiotics, and the cells that have incorporated the foreign DNA and the resistance genes from the vector grow, while those that haven’t been modified die" (Teitel 9).

What this means is that scientists are now able to produce genetic combinations that would have been impossible in nature. Fish genes can be spliced into tomatoes, bacterium genes in corn, and human genes in tobacco (Teitel 9). This knowledge has undoubtedly changed the face of agriculture forever. About 60 percent of our processed foods now have some genetically engineered ingredients in them ("What's" 19). In fact, a handful of large corporations have even put patents on food plants, giving them specific control over that food (Teitel 2). "Not individual sacks of wheat or grain, but entire varieties of plants are now corporate products" (Teitel 4). In some cases, entire species are owned (Teitel 4). It gives new meaning to the word "monopoly" when one imagines large corporations actually owning major portions of the world's food supply.

Furthermore, there seems to be no benefit to the consumer as to whether or not the food they are eating was altered or not. It doesn't look or taste better, cost less, or have better nutrition (Teitel 2). In fact, it is almost impossible to distinguish a genetically engineered plant from an ordinary one without looking at the plant's DNA (Teitel 2). In order to make the distinction, people give them different names. In Europe, they are called "GMO food." In the United States, the term "genfood" is used (Teitel 2).

There has been a lot of controversy associated with the genetic engineering of food. Many people question the safety of such products. Some even call them "frankenfoods". According to Malin, at this point, there is no proof as to whether of not these foods are completely safe to eat. She says, "One-quarter of our farm fields are now filled with genetically engineered crops-including more than 35% of all corn, almost 55% of all soybeans, nearly half of all cotton, and a growing array of fruits and vegetables. Some of that ends up in our salads, oils, side dishes, and snacks" (122). Clearly it is a concern to many people that "frankenfoods" are becoming a considerable part of their diet.

There are several concerns about how safe these products are for human consumption. One such concern is whether or not these foods will contain hidden allergy-inducing ingredients. People with food allergies know for the most part what foods they need to avoid. However, as genes from plants get implanted into other plants, that line might be blurred. For example, the seed company Pioneer Hi-Bred International tried implanting some Brazil nut genes into soybeans to boost their nutritional value. However, they cancelled the project after some human volunteers had strong allergic reactions to the beans (Malin 123).

Another concern is whether or not engineered foods increase resistance to antibiotics. When genes are transferred from one organism to another, a "marker" gene is included. "This helps them identify and select the cells that have successfully taken up the gene of interest, but also confers antibiotic resistance" (Malin 124). Some scientists argue that this worry is miniscule when compared to overuse of antibiotics by doctors and livestock farmers. "These resistance genes are already very widespread in naturally occurring bacteria. What little would be added by cloning is like adding a cup of water to the ocean," says Abigail Saylers, Ph.D., professor of microbiology at the University of Illinois in Urbana (Malin 124).

There is also a concern as to whether or not genetically engineering food will change its nutritional value. Marc Lappe, a health policy expert and director of the Center for Ethics and Toxins in Gualala, CA, tested some soybeans that were resistant to a herbicide called "Roundup." She found that these soybeans contained 20 percent fewer phytoestrogens, which may be beneficial in fighting osteoporosis and heart disease, than ordinary soybeans (Malin 125). However, Lappe admits that more testing needs to be done before we can anticipate any drastic changes in nutritional value (Malin 125).

Whether or not engineered foods can be toxic is yet another concern. In a study in which rats were fed engineered potatoes, the rats showed signs of intestinal changes (Malin 125). The researchers who conducted the study suggested that the genetic material used to make the plants more resilient to pests might have caused the rat's intestines to thicken, but say that they "hesitate before using such words as 'poisonous' or 'toxic' "(Malin 125). Some studies have concluded that the implanting of a gene from one organism into another may have unpredictable consequences. "They have this model in which they're putting in, with laser precision, one or two new genes, and this is going to change just one or two traits. Otherwise this organism will be just like any other crop out there," says John Fagan, Ph.D., a molecular biologist and former genetic engineer (Malin 127). But he is quick to point out that "living things are very complex and that all of the components interact. So when you change one gene, you change a whole slew of other things as well-and you can neither predict those changes, nor can you control them" (Malin 127).In 1992, the FDA decided not to regulate engineering of crops.

"In fact, the FDA considers it not substantially different from the kind of conventional crop breeding that farmers have been doing for centuries (Malin 122)." They don't require safety testing or labeling of these products. A few exceptions to this are when the food's nutritional value is significantly altered or when it contains a known food allergen. For the most part, it is up to the food manufacturers to make sure their products are safe (Malin 122).

Despite the fact that agriculture has been around for thousands of years, we are only now beginning to understand what it is that determines the traits of each plant. Moreover, we are learning how to alter those traits to better meet our own needs. Many people are concerned about what kind of consequences this "genetic tinkering" may have on the safety of our food. Despite these concerns, more and more of our food is being genetically altered, and the true benefits or consequences of that may not be known for many years to come.

Genetic Engineering of Plants. Washington DC: National Academy P, 1984.

LeRiche, W. Harding. A Chemical Feast. Ontario: Methuen Publications, 1992.

Malin, Andrea. "Are You Eating Test Tube Food?" Prevention May 2000: 122-132.

Teitel, Martin, Ph.D. and Kimberly A. Wilson. Genetically Engineered Food: Changing the Nature of Nature. Rochester, Vermont: Park Street P, 1999.

"What's Really In Your Food?" Prevention May 2000: 19