How do GM foods work? Genes are the instructions that give organisms their characteristics. These instructions are stored in each cell of every living organism in a long string-like molecule called DNA. The full set of instructions is called a genome. All organisms have genomes of varying sizes; for instance the human genome has an estimated 60-100,000 genes; most plants have about 20,000; the nematode worm (a microscopic creature) has about 18,000; and the single-celled Escherichia coli bacterium has just over 4,000.
Our knowledge of genetics allows the identification of individual genes, and often understanding of their specific properties. The technique of genetic modification (also known as genetic engineering, and genetic manipulation) allows those individual genes to be cut out of the genome of one organism and pasted into the genome of another.
Deoxyribonucleic acid (DNA) is the genetic material of all plants, animals and bacteria and of many viruses. It is made up of just four building blocks called nucleotides (or bases) - Adenine (A), Cytosine (C), Guanine (G), and Thymine (T). It is the linear sequence of these bases that contains the genetic information. Rather like Morse code, only instead of two elements (dots and dashes) the DNA code has four - A, C, G, T. DNA usually exists as two separate strands, twisted together in the well known double helix pattern. The genetic difference between species, and organisms within a species, lies in the different ordering or sequence of these bases and the genes that they form.
In the first genetic modification experiments, which took place in the mid 1970s, synthetic human genes were combined with genes from a bacterium. Many apprehensions of possible dangers were raised at this time. They were carefully addressed by the scientific community (in particular at a noted conference in Asilomar), and none of these conjectured problems have actually arisen. Later that decade, researchers learned how to insert genes into fungi and yeast. In the 1980s, they found ways of putting foreign genes into the cells of plants and some animals. In the 1990s, the first experiments to insert new genes into human cells and tissues were developed.
In principle, genetic modification allows researchers to move genes between all living creatures. In practice, so far it has only been made to work in a few animal, plant, and microbial species � usually organisms that humans have used for many years in agriculture, food manufacture, and industry.
What is perhaps most surprising about genetic modification methods is that they work at all. How is it possible that genes from one organism can be processed by an unrelated organism? The answer lies in the fact that DNA has the same basic characteristics in all organisms. Because all DNA is composed of the same basic ingredients, a gene pasted from, for example, a simple organism like a virus can in principle function in the same way in a more complex organism like a plant. Modern computer databases containing huge amounts of sequence data from large-scale genome projects are making the task of identifying genes with particular desired characteristics (e.g. the gene that codes for production of vitamin C in citrus fruit) far easier than in the past. Once identified and isolated, gene sequences can be cut and pasted into bacteria, which then manufacture multiple copies of the genes. This enables, for example, the production of essential medicines like insulin to be produced from GM bacteria rather than from animals. Such insulin is produced in a cleaner, more controllable environment than was previously the case. Other sequences are often introduced at this stage, for instance, selective marker genes conferring resistance to one or more antibiotics are often linked to the trait genes to allow researchers to pick out only those bacteria that have successfully received the new gene sequences. Extra regulatory sequences may also be added at this stage, to control the gene's expression i.e. whether it should function only in certain parts of the new host, or `switch on' at a certain stage of its development.
Once the gene is complete within the `carrier', it needs to be inserted into the new host. For GM plants and animals, this stage is complicated by the need to introduce the genes into all the cells in the organism. This can be achieved by inserting the prepared genes into a single cell of the new host. This single cell can then be cultured into a whole organism in which all the cells contain a copy of the introduced gene (the process works similarly if a gene is removed instead of added). A number of methods are used to insert genes into cells. Bacteria and yeasts are often encouraged with chemical and electrical treatments, and disarmed viruses can be used to carry genes into animal, plant and human cells. There are also direct ways of taking genes into cells: by injecting them with very fine needles or by forcing them in aboard tiny metallic bullets. Amazingly, these techniques do not damage the cells.
The introduction of GM crops may be the only way to provide food for future generations. When asked if genetically enhanced crops will allow us to end famine, Nobel-Prize winner Norman Borlaug said that �With the technology that we now have available, and with the research information that�s in the pipeline and in the process of being finalized to move into production, we have the know-how to produce the food that will be needed to feed the population of 8.3 billion people that will exist in the world in 2025.� Famine has been an altogether too familiar problem in the past, and with populations on the rise, there is no other current solution. Since the introduction of GM crops, some disastrous famines of the past have been avoided. According to �Human Geography� the seventh edition, India became self-sufficient in grain production by the 1980�s, and Asia saw a two-thirds increase in rice production between 1970 and 1995. This increase is due mostly to the introduction and evolution of �artificial� rice strands like IR8, which is a cross between a Chinese dwarf variety, and an Indonesian variety that produces a larger grain �head,� and therefore more food per grain. Further modifications produced IR36, which incorporates other advantages of GM to obtain rice that is larger, can produce more crops per year, and is genetically resistant to 15 different pests. There are other crops that may benefit from genetic engineering, and there are other ways that GM crops can have a positive affect.
Another benefit to many GM crops is the increase in nutritional value of the foods that we currently eat. Just as the introduction of Iodine to table salt in the US has led to a significant decrease in the number of Rickets cases every year, genetic additives to current foods my increase the standard of living of millions of people. According to the U.N., as of 2000, there are nearly 800 million people around the world that are undernourished. Around 400 million women of childbearing age are iron deficient, which means that their babies are exposed to various birth defects. It also states that approximately 100 million children suffer from vitamin A deficiency, a leading cause of blindness. The development of �Golden Rice,� a genetically modified rice grain is fortified with beta-carotene, which the body can convert into vitamin A, additional iron, and a daffodil gene that provides vitamin K.
One of the major problems facing farmers throughout the US and the world are agricultural pests. Spraying pesticides and herbicides can pollute ground water, affect local flora and fauna, and have other adverse affects on the environment. GM crops offer a pest resistant plant that doesn�t need the constant spraying of pesticides over month long periods. Bacillus thuringiensis (Bt) genes for insecticidal proteins, herbicidal tolerance, and virus resistant crops have been incorporated into corn, cotton, soybeans, squash, cucumbers, and papaya. According to �Genetically Engineered Foods,� 45 percent of farmers in 1998 reported higher yields of Bt corn compared to conventional corn, and nearly 26 percent reported a decrease in pesticide use. This will also help to prevent the pests from being able to build a tolerance to pesticides, by genetically incorporating insecticides, instead of repetitive spraying that leaves just the stronger more resistant species alive.
The last major benefit of GM crops is a byproduct of the other benefits. By increasing the yield of each crop, increasing the nutritional value of the crops, decreasing the amount of diseases or ailments attributed to malnutrition, decreasing the amount of necessary pesticides or herbicides, and therefore alleviating the need for environment clean-up costs can lessen the economic pressure on a country to provide food for its people. Provided that the government uses the economic resources gained by GM crops to increase the quality of living for the residents of that country, the rewards would far outweigh the drawbacks.
The possibilities of GM crops are limitless, and further testing and scientific inquiry is needed to gain the advantages to be gained from GM foods. GM foods can produce higher yields than organic crops, they are safer than organic foods in that organic fertilizers are breeding grounds for E. coli and there are no cases of GM foods causing an illness in humans. GM foods provide more nutritional value per capita, decreasing malnutrition related illnesses and afflictions. GM crops also require less pesticides and herbicides, meaning a lower cost and cleaner crop than organic crops. GM crops will also alleviate some of the economic pressure on a country to provide food for its citizens. New possibilities are constantly arising as well. The incorporation of hepatitis B virus vaccinations into banana plants, and cancer fighting agents added to tomatoes and strawberries may provide medical benefits. Decreasing the amount of saturated fatty acids in foods and oils can benefit the health of millions of people. There is even work being done to remove the allergy provoking proteins from peanuts and rice, possibly saving thousands of lives per year. There are always drawbacks to every change, but the benefits of GM crops not only outweigh the drawbacks, they negate them completely. We can either allow GM crops to be utilized, or millions of people can starve every year.