Genetic Engineering

Genetic Engineering By Nathan Smith

Four-legged chickens with no wings; goats whose milk contains the silk of spiders; “Round-Up Ready” soybeans; seedless watermelon; “sweet, silver queen” corn

—whatever happened to “all-natural?” How does seedless produce reproduce itself? Why do so many unnatural products hold such a staggering presence in our food supply? How is it that the very disease-causing bacteria against which humans fight are now producing the medicines with which we fight them? All of this and much more can be explained by genetic engineering. Genetic engineering is the manipulation of an organism’s genetic information by introducing or eliminating specific genes. Other terms often used for genetic engineering (GE) are genetic alteration (GA) and genetic modification (GM).

After reading this report, the reader should be aware of the different processes of GE, have a basic understanding of gene splicing, and have been given a glimpse into how GE has had an impact on the food supply of the United States.

There are several different processes used to genetically engineer a subject. The oldest, most reliable method is called selective breeding. An example of this would be when one breeds a female horse with a male donkey to get a mule. This has been practiced for thousands of years and is considered common knowledge to many. Another type of GE is called hybridization, which is very similar to selective breeding. The difference between the two is this: selective breeding chooses two subjects with overall desired traits; hybridization focuses on one desired trait that is present in both subjects.

The result of hybridization may be an ear of silver queen corn, just about the sweetest corn around. A third type of GE is called gene splicing. This is the most advanced, yet the most complicated, process used to genetically alter an organism. Gene splicing occurs when a gene from one organism is transplanted, or spliced, into the DNA of another organism. A gene is simply a small section of the DNA strand. Using complex proteins, scientists can cut the gene out of the DNA and splice it into new DNA by cutting the new DNA with proteins. The gene being transferred has all of the needed information to perform certain functions. When this is incorporated into the DNA of another organism, the new DNA will begin to function accordingly. Gene splicing has a potentially bright future, but it is presently the most unpredictable, and, therefore, the most controversial process of GE.

An added gene affects the genes on either side of it in the DNA strand. If the gene is spliced into a different position, then it will have a completely different effect on the organism’s abilities and functions. No one really knows what the outcome of any experiment will be. They may successfully achieve the desired effect, but there is no telling what undesirable traits are waiting to be unleashed.

Cloning is a type of GE. The difference is that cloning involves the complete transfer of a cell nucleus as opposed to a single gene. Another type of GM is called a transformation. It could be defined as the uptaking of DNA by an organism.

Transformations are gene transplants on a very elementary level. In fact, some transformations can take place naturally. One example of this involves Escherichia coli, or E.coli. E.coli bacteria will pick up any DNA molecules they happen across. They transport the DNA molecule—also called a plasmid—into the nucleus of their cell. If there is enough similarity between their DNA and the plasmid, then they will incorporate it into their own DNA and reproduce. All of the offspring then contain the GM DNA. This is seen in nature when a harmless type of E.coli comes across the remains of pathogenic E.coli. The living bacteria uptake the plasmid of the dead E.coli and recombine its DNA to contain the pathogenic traits of the deceased E.coli. The living

E.coli bacteria is now a pathogenic strain capable of causing disease in animals and humans.

I was given the chance to carry out a genetic engineering experiment myself. I performed a transformation on E.coli, similar to the one described above. Except in my experiment, I gave the bacteria two new traits: resistance to ampicillin, an antibiotic, and bioluminescence, the ability to glow in the dark. By following the laboratory procedure, the following occurred. The E.coli bacteria was put into two separate test tubes containing a solution of calcium chloride at a low temperature. I then mixed in the plasmid DNA containing the desired traits. I only put the plasmid into one tube of solution so as to have two separate lab results. The next several steps involved cooling the test tubes, then heat shocking them in warm water and returning them to the ice. After all of this, I transferred the bacteria to Petri dishes containing ampicillin. If the experiment was successful, E.coli would grow on one dish and not on the other. This would show me that the E.coli had successfully reconstituted its DNA to include resistance to ampicillin. On top of that, it should glow in the dark.

After allowing it to incubate at 25°C for only 24 hours, the new bacteria containing the recombinant DNA began to grow. It was obviously resisting the antibiotic, and when examined in a dark room, its bioluminescence was very evident. The experiment was a great success as well as a wonderful learning experience for me. I now see that I really didn’t genetically engineer the E.coli, but rather I set it up to genetically engineer itself. All it needed were the right conditions with some plasmid DNA and it handled the rest.

Genetic engineering is widely used in America’s food supply. Researchers have come up with the following facts and statistics. First, the United States is just about the only country that has not established any bans, restrictions, laws or regulations on genetically altered foods. No company is required to inform the consumer of the presence of GM ingredients. Second, around 90 million acres of U.S. farmland is growing GM crops. This constitutes nearly ¼ the total farmland in our country. Third, 30% of all U.S. dairy cows are fed genetically engineered grains and injected with genetically engineered hormones. And fourth, 50-60% of processed foods in the US contain genetically altered ingredients.

What does this mean? It means that when you shops in your average grocery store, 75% of what you buy is genetically altered in some way. Do you find this hard to believe? Here is a short list of some American food companies that currently use genetically engineered foods: Frito, Kellogg’s, Kraft, McDonald’s, Nabisco, Nestle,

Pillsbury, etc. Another brief list I will mention is only some of the altered foods on the market:

Corn Candies Eggs Chips Chocolate Papayas Cookies Peanut butter Margarines Gum Baby food Beer Breads Potatoes Wine Cereals Soups Fruit juices Alcohol Sauces Sugar Pastas Tomatoes Enzymes Salad dressings Milk Vitamin C Vanilla Butter Ice cream Cheeses Yogurt Most meats Again, that was only a brief list of what is already on the market. Here is a glimpse of what may be on its way:

Rice Catfish Peppers Strawberries Broccoli Bananas Lettuce Sunflower seeds Trout Barley Grapes Peas Pineapples Cauliflower Chestnuts Beets Wheat Apples Cucumbers Salmon Carrots Melons Sweet potatoes Walnuts

To sum up everything I have learned, genetic engineering is an ever-growing field of study with some amazing potential, especially in the medical field. However, without any control over it, GE could prove to be very disastrous to plants, animals, even humans.

We must realize with what a powerful force we are dealing and proceed with great caution. To carelessly manipulate the code of life that has been instilled in us would be an extremely senseless thing to do; with time and patience, though, I’m sure we can figure out the best uses for genetic engineering. Sources

Processes of Genetic Engineering http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid-761557775

Transformations of E.coli

Transformations; Dr. Maria Rapoza & Dr. Helen Kreuzer.

Genetically Modified Facts & Foods www.country-spice.com/webpages/healthreports/gmofoods.htm