Agricultural Genetic Engineering
Food not only provides us with the energy we need to carry out our lives, but it also is an art form and a comfort to many. Sitting down at the table to eat nightly, especially during holidays, gives us a chance to spend quality time with family and friends. Meanwhile, the food we are enjoying may be altered as knowledge of the genetic world increases. These revolutionary modifications could change how food tastes and appears as well as its cost and method of production. In addition, there may be ecological and moral repercussions that accompany these changes. It is crucial to provide education about genetically engineered foods to the public, who will be deeply affected by this technology and who will determine the market for these foods. One way to offer a comprehensible and nonbiased introduction to genetic engineering is through a museum exhibit
The first room in the exhibit would describe the role of DNA in genetic engineering, and explain the mechanics of the process. This room represents the cell, containing all of the basic organelles and the nucleus suspended in it. In the center, there are rows of seats for the visitors. First there is a short video, telling the audience that genetic engineering is changing the characteristics of organisms by manipulating their genes or transferring them from one organism or even from one species to another. The video provides an overview that explains how genetic engineering can alter the future of the food we eat. There is also a quick history of agricultural modification. This includes selective breeding, which is the pairing of naturally healthy and high-yielding animals and plants. Hybrids, which are crops and animals that possess a combination of desired characteristics due to the crossing of parent lines that are inbred to have one dominant trait, will also be discussed.
Next, the room darkens in preparation for the sequence showing how DNA controls the characteristics of every organism. The video shows the structure of a DNA molecule. It is a double helix containing the nucleotide bases guanine, cytosine, thymine, and adenine. As the processes of transcription and later translation are described, various components of the Cell Theater are illuminated for further visual aid.
DNA is a large molecule confined to the nucleus of the cell that contains the genes of an organism. For this reason, the reverse of the genetic code in DNA is transferred onto smaller and more mobile messenger molecules of messenger RNA (mRNA). The mRNA then departs from the nucleus and moves through the cytoplasm to organelles called ribosomes, which are where proteins are made. Translation is now shown. The mRNA determines the sequence in which amino acids are synthesized to make proteins. There are twenty amino acids and twenty corresponding forms of transfer RNA. One end of the transfer RNA (tRNA) links with the resembling coding sequence on the mRNA. The other end links with the equivalent amino acid. Through this system all genetic information is transferred from DNA to proteins. It will be explained to the audience that proteins include enzymes, which control all chemical reactions in the body, and hormones, which direct growth and reproduction. Consequently, by altering genetic code, scientists can modify the characteristics of organisms, crops, and farm animals.
The video then describes how genes can be manipulated. Scientists first must locate a single gene that controls a beneficial trait. This is a very difficult task, because there are thousands of genes and many genes work together to operate a characteristic. The gene is then cut with restrictive enzymes, cloned, and transferred to another organism. In plants, any cell can be used as a host for this gene, because a cell from any tissue can be used to grow an entire plant. In animals, the gene must be inserted into a fertilized egg and placed in a surrogate mother to be effective. There are several methods of gene transfer. The most convenient is through a soil bacterium, argobacterium tumefaciens, that infects tomatoes, potatoes, cotton, and soybeans. This bacterium attacks by inserting its own DNA. When genes are added to the bacterium, they are transferred to the plant cell along with the other DNA.
Another gene transfer method is shooting a microscopic bullet coated with DNA into a plant cell with a special particle gun. Still another method is electroporation, the process of placing plants in DNA containing fluids and applying an electric charge. The cell wall then opens for less than a second, allowing DNA to seep into the cell. Finally, genes can be transferred by microinjection (piercing an egg with a tiny needle and inserting DNA). An organism containing a gene from another organism is said to be transgenic. After the transfer is made, scientists must wait to see if it was successful. To make sure if the new genes are in the organism, marker genes are sometimes inserted along with the desired trait. One common marker gene is the resistance to the antibiotic kanamycin. Scientists are therefore able to know for certain if the transfer was successful when the organism resists the antibiotic. A simpler way to genetically engineer an organism is by altering the genes already found within it.
After learning about DNA and genetic transfer in the Cell Theater, visitors move into the second room, which primarily contains information about the uses of biotechnology in plants. The first display in the room consists of two enclosed cases containing plastic stalks of corn--one representing conventionally grown corn, and the other standing for genetically engineered corn. Some of the corn stalks that represent conventionally grown corn have the typical signs of disease, and insects can be seen on them. There is also a bag of chemical fertilizer in the display. In the other case representing genetically engineered corn, the corn stalks look healthier and do not have insects. There are more ears of corn per stalk. Also, there is no fertilizer on the transgenic plants. Beneath the corn stalks there is a board explaining the display. Genetic engineering is being used to make crops disease- and insect- resistant. Crops are also being made herbicide resistant, so that when farmers use chemicals to kill the weeds in their field, their crops will not be damaged as well. Genetic engineering can give plants the gene that allows them to fix nitrogen from the soil and air. This innovation will reduce the necessity for fertilizer, which is highly composed of nitrogen. Finally, biotechnology can increase the yield per acre of many crops.
The next exhibit in this room shows that genetic engineering may be used to grow crops in areas that have a cold climate or poor soil quality. It consists of a large, wall-mounted map of the world, with all the areas in which crops are grown lighted by bulbs behind the map. When a button is pressed, areas where it would be possible to grow genetically engineered plants will be illuminated with different colored light bulbs, increasing the total area of crop growth on the map.
Visitors can then view an oversized picture of food being packaged. Under this picture is a board explaining that transgenic foods may be more durable for shipping, ripen at a slower rate, and stay fresh longer. All of these improvements will help the food-packaging and shipping industries.
A representation of a future supermarket aisle serves as the fourth display. It will be an aisle containing vegetables, including broccoli, carrots, greens, cabbage, spinach, and asparagus. This exhibit illustrates that in the coming years, vegetables may be genetically engineered to have increased health benefits. This may occur by increasing the amount of cancer-fighting substances, known as photochemicals. Examples of this are cabbage with more sulforaphane, which prevents tumor growth, or carrots with more beta-carotene found in them. Other ideas are low-fat vegetable oils and better-tasting vegetables that would encourage people to eat more healthily.
The last exhibit in this room represents the role of microorganisms in biotechnology. It is a finely set table with a bottle of wine, a basket of breads, and wedges of cheese. By genetically engineering yeast and other microorganisms, the texture and taste of these foods may be improved.
Visitors then enter the third room in the exhibit. This portion concentrates on altering the traits of animals through biotechnology. The setting is a barn with hay strewn on the floor for an authentic touch. In the first stall there are models of cows. Here, the genetic engineering of cows for their milk is discussed. Bovine somatotropin is a growth hormone that is produced in the pituitary glands of cows. Genetically produced bovine growth hormone was introduced in 1994. When cows are injected with this hormone, their milk production can increase by up to 15 percent. Research concerning the modification of cow milk to more closely resemble the makeup of human milk is also being conducted. This milk may assist the infants of the future in their developing years. In addition, scientists are researching the use of animals' blood and milk as production sites for proteins that would be placed in medicinal drugs.
In the adjacent stalls are models of pigs and chickens. Genetic engineering may be able to create leaner pork and chickens that are disease-resistant. Beyond the barn setting is an aquarium with large fish swimming in it. It is explained here that fish may also be genetically engineered. Their desired traits include larger size and the ability to live in colder water than that of their natural habitat.
The final room in the exhibit further discusses the positive uses of genetically engineered food; however, it also includes some of the risks of the technology. The first model the visitors see in this room will be used to open the discussion of who is sponsoring biotechnology research. There is a model of a person in a lab coat looking through a microscope. Since chemical companies are now becoming involved with seed production, farmers are buying their seeds as well as pesticides and fertilizers from one company. It is possible that this type of monopoly could put profits ahead of safety measures, a situation that could be harmful to the public. Companies are also funding university research. In this system, university scientists receive payment for their research if they agree to release their discoveries only to the company that is paying them. Some feel that this is not a trustworthy system, because the public is not being informed on the findings of the scientists.
The second model is of a farmer and his son standing over a plot of earth planted with tomatoes. This model raises the question of how genetic engineering will affect the family farm. It is probable that this new way of farming will cause farms to grow and further lessen the prevalence of family-operated farms. Another source of opposition to genetic engineering comes from farmers, who practice subsistence and natural agriculture. The priority of these organic farmers is to exercise good soil- and water- conservation methods. They anticipate that herbicide-resistant crops will only increase the amount of herbicide sprayed onto fields. They are against the incorporation of a bacteria (bacillus thuringiensis) gene into crops, because they believe it will lead to insects that are resistant to this bacteria, which is routinely used as an insect repellent by organic farmers. A last ecological concern is that if crops were crossed with weeds in an effort to make a stronger variety, weeds with resistance to insects, disease, and even herbicide could be created.
In the middle of the last room there is a can of spaghetti with a label that says the tomatoes, grain, and beef used to make this product were genetically modified. The label also tells the consumer exactly what gene crossings were performed. This can of spaghetti brings up the controversy of labeling transgenic foods. While some feel it is necessary to tell consumers if their food is altered, others think it is costly and unessential. The current government policy is that labels are only required if genetic engineering substantially changes the nutritional content of the food. Labels were also required for food crossed with allergy-causing genes; however, it was later decided that these foods should be altogether banned from the market.
The fourth presentation consists of a globe with the places of serious hunger problems lighted, and pictures from these places mounted on the wall. The visitors will learn that world hunger may be able to be reduced through biotechnology, as it can increase food production through disease- and insect-resistant crops and crops that can be grown in poor soil and harsh climates. Nevertheless, for this to become a reality, advanced countries must be willing to share their technology with Third World nations, and research transgenic crops that are indigenous to these nations.
In addition to the three-dimensional models supported by textual information found in this room, there are a few computers. On these computers are educational games that can be enjoyed by both children and adults. One such game is called "The Refrigerator of the Future." Visitors can open this virtual refrigerator and click on the various foods inside of it. Each item will present an example of a possible transgenic food of the future.
Next, there is a board on the wall that is covered with pictures of plants, animals, and the Earth itself. Here, philosophical concerns are raised. Are we playing God or obstructing nature through genetic engineering? Is it morally incorrect to put human genes into plants and animals? How will vegetarians be protected from eating plants that contain animal genes in them? Finally, there is a board summarizing the benefits and risks of genetic engineering. It also gives the public the feeling that much of the future of biotechnology depends on their willingness to support or their readiness to oppose these altered foods.
The aim of this museum exhibit would be to educate the public about the ever-increasing advances in agricultural genetic engineering. It would provide a factual overview of the topic and hopefully inspire visitors to further study this matter. The exhibit would cause people to realize that imaginative uses of genetic engineering are now becoming realities that will affect the entire world as we enter the twenty-first century.
Fox, Dr. Michael W. Superpigs and Wondercorn: The Brave New World of Biotechnology...and Where It All May Lead. New York: Lyons and Burford, 1992.
Marshall, Elizabeth L. High-Tech Harvest: A Look at Genetically Engineered Foods. Danbury, CT: Franklin Watts, A Division of Grolier Publishing, 1999.
Nottingham, Stephen. Eat Your Genes: How Genetically Modified Food Is Entering Our Diet. New York: Zed Books Ltd., 1998.
More About This Resource...
Less than 1 period
Supplement a study of genetics with an activity drawn from this winning student essay.
- Send students to this online article, or print copies of the essay for them to read.
- As a class, create a list of what students believe are the biggest benefits and risks of genetically engineered food.
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