Feature

Genetic Engineering- the future of Food and medicine

Zakaria Ahmed

The world population continues to increase at an explosive rate, our arable land is deteriorating, fresh water is becoming scarce and increasing environmental stresses will consistently pose serious threats to global agricultural production and food security in future years. Bioengineering or genetic engineering refers to new methods of plant breeding that permit scientists to improve food crops by introducing a copy of a gene for a specific trait (e.g., fruit softening). Genetically engineered foods are produced from crops whose genetic makeup has been altered through a process called recombinant DNA or gene splicing, to give the plant a desirable trait. Genetically engineered foods are also known as biotech, bioengineered or genetically modified; although "genetically modified" can also refer to foods from plants altered through other breeding methods. Scientists and farmers have been genetically modifying plants for hundreds of years. Hybrid corn and tangelos, for example, are the result of genetic modification through traditional methods of plant breeding and the many varieties of apples we eat today were produced through genetic modification. Using traditional genetic modification methods, such as cross-fertilization, scientists can produce a desired trait, such as a hardier plant. But in doing so, they mix thousands of genes from several plants, requiring many attempts over many years to weed out the unwanted traits that occur. Newer methods of genetic modification, in the form of genetic engineering, are more precise, predictable and faster. By controlling the insertion of one or two genes into a plant, scientists can give it a specific new characteristic without transferring undesirable traits.

Genetically modified foods
Tomatoes, potatoes, squash, corn and soybeans have been genetically altered through the emerging science of biotechnology. For example, scientists have developed a variety of rice capable of synthesizing beta-carotene, a precursor to vitamin A, by inserting genes from a soil bacterium and two genes from a daffodil. Although it is the staple food for half of the world's population, rice is a poor source of many essential nutrients and contains no vitamin A. The genetically engineered rice someday could help millions of people worldwide who suffer from vitamin A deficiency- a condition that leads to blindness in quarter million children annually in Southeast Asia. Scientists can also use the same procedure of inserting genes and a promoter to create biotech wheat, corn and other cereal plants that can withstand harsh conditions.

The first genetically engineered whole product- a tomato -went on the market in 1994. The Grocery Manufacturers of America estimates that between 70-75 percent of all processed foods available in U.S. grocery stores may contain ingredients from genetically engineered plants. Breads, cereal, frozen pizzas and soda are just a few of them. Soybean oil, cottonseed oil and corn syrup are ingredients used extensively in processed foods. The first generation of genetically engineered crops was developed primarily to benefit the growers. Plants were created to resist pests and diseases and to tolerate herbicides used to kill weeds. Scientists see the next generation of genetically engineered products benefiting the consumers directly. They are adding nutrients to foods to help prevent diseases, reducing allergens and toxins, and making foods tastier.

Using the tools of biotechnology, researchers are working to reduce the bitterness in citrus fruits, reduce saturated fats in cooking oils, produce more flavorful tomatoes, and even lessen the gassiness caused by beans. Grains, fruits and vegetables that contain more nutrients and potatoes that absorb less oil when made into chips and French fries are also in the development pipeline.

Scientists have inserted into corn a gene from the bacterium Bacillus thurigiensis, usually referred to as BT. The gene makes a protein lethal to certain caterpillars that destroy corn plants. This form of insect control has two advantages: it reduces the need for chemical pesticides, and the BT protein, which is present in the plant in very low concentrations, has no effect on humans. Another common strategy is inserting a gene that makes the plant resistant to a particular herbicide. The herbicide normally poisons an enzyme essential for plant survival. Other forms of this normal plant enzyme have been identified that are unaffected by the herbicide. Putting the gene for this resistant form of the enzyme into the plant protects it from the herbicide. That allows farmers to treat a field with the herbicide to kill the weeds without harming the crop. The new form of the enzyme poses no food safety issues because it is virtually identical to nontoxic enzymes naturally present in the plant. In addition, the resistant enzyme is present at very low levels and it is as easily digested as the normal plant enzyme.

The discovery that deoxyribonucleic acid (DNA) was a sort of biological "software" in the mid-1950s set the stage for today's bioengineered foods, pharmaceuticals, transgenic animals and gene therapy. DNA molecules contain the genetic information necessary for life. This information is contained in four chemical bases: adenine, cytosine, guanine and thymine. Specific chunks of DNA that carry the codes necessary for the production of a specific protein are called genes. These proteins contribute to the expression of a specific trait by stimulating biochemical reactions or by acting as structural or storage units of a cell. The fact that DNA is a genetic building block in all organisms makes it possible to insert a gene or genes into plants instead of relying on cross-pollination. The inserted gene, called a trans gene, may come from an unrelated plant or even from bacteria, viruses or animals.

Medicinal value of Bioengineered food
Biotechnology also has the potential of creating major advances in medicine. Plants may become miniature "factories" for pharmaceuticals through genetic engineering. Scientists are growing plants that produce antibodies to help fight cancer, heart disease and tooth decay. And researchers are experimenting with growing fruits and vegetables that contain vaccines for measles, hepatitis B, Norwalk virus, diarrhea, cholera and more. These edible vaccines could be pureed into an applesauce-like consistency and fed to children and adults alike. They could be produced in larger quantities and at less expense than current vaccines.

The debate over genetically engineered plants
The debate over genetically engineered plants began almost as soon as scientists learned to directly alter the genes in plants in the early 1980s. Opposition to bioengineered foods has been especially strong in Europe and Japan. Concerns include ethical issues related to potential long-term health effects of eating bioengineered foods and potential environmental risks. Some worry about the possibility of introducing new allergens into foods such as those found in peanuts, wheat and soy. Others worry about the potential effects that altered crop species may have on wildlife and other plants. All of the proteins that have been placed into foods through the tools of biotechnology that are on the market are nontoxic, rapidly digestible, and do not have the characteristics of proteins known to cause allergies. However, many researchers say the ability of biotechnology to isolate and introduce a specific gene or just a few genes makes outcomes more predictable, including the ability to predict risks. DNA is present in all foods and its ingestion is not associated with human illness. Some have noted that sticking a new piece of DNA into the plant's chromosome can disrupt the function of other genes, crippling the plant's growth or altering the level of nutrients or toxins. These kinds of effects can happen with any type of plant breeding--traditional or biotech. If the plant looks normal and grows normally, if the food tastes right and has the expected levels of nutrients and toxins, and if the new protein put into food has been shown to be safe, then there are no safety issues. Supporters say that biotechnology is a tool that allows scientists and farmers to reduce damage from pesticides, boost crop yields, and improve flavor, texture and nutritional content.

Bioengineered foods will not solve all of the world's nutritional and agricultural problems. However, the techniques used to develop them will play an important role in boosting food production, improving nutrition, and reducing the needs for herbicides and pesticides. It is important to know that bioengineering does not make a food inherently different from conventionally produced food and the technology does not make the food more likely to cause allergies.

Writer is Assistant Professor, Department of Microbiology, Primeasia University