Genetically Modified Crops
Part 1 of 3 - 1 | 2 | 3

Koushik Seetharaman
Department of Food Science

In October of 2000, the detection of the genetically engineered StarLink corn in Tacos and several other food products caught the attention of American consumers. During the last week of February, it was reported that most of the corn seeds ready for planting this year are contaminated with StarLink corn. Farmers and federal regulators, consequently, face a dilemma about what corn to plant. Americans are also increasingly aware of protests around the world objecting to genetically modified foods, identifying them as frankenfood or as environmentally unfriendly.

These recent news items have re-ignited public debate over the technology of genetically altering crops. This and the subsequent two articles in future issues of this newsletter will attempt to address some common issues related to Genetically Modified Foods and the technology of genetic engineering. Part I will delve into the background of genetic engineering and the future of genetically altered foods; Part II will address issues related to the benefits and drawbacks of this technology; and Part III will delineate, in simple terms, the basics of how genetically modified organisms are created.

Part I: Background

Selective plant breeding is not a new concept. Casual selection of observed desirable traits by our ancestors essentially tamed wild plants and made them suitable for agriculture. In the past, if pests devastated a field of crops and a few plants stayed alive and healthy, the seeds from these healthy plants were used to generate the next crop. Thus the beneficial factors that made the plants resistant were transferred to the next generation, making the new generation of crops slightly more resistant to the same pests. Such selections have been used for over 10,000 years, since the beginning of agriculture and have resulted in significant advances for humanity with increased yields, disease resistance and, overall, greater productivity. A good example is corn; the original crop was Teosinte with very small seeds and very few seeds in each cob. Over the centuries people selected for various traits thus improving the size of the corn kernel, the number of kernels in each cob, the stronger attachment of the kernels to the cob so that it could be harvested and so on, resulting in the corn that we are familiar with today.

It has since become evident that all traits, beneficial or otherwise, are conferred to living organisms by genes. Genes are small segments of the DNA (deoxyribonucleic acid) that code for specific proteins, which in turn regulate the various traits in all living organisms. There are thousands of genes in plants that regulate the activities governing the growth, stature, color, and all other aspects of plant growth and survival. Selection through traditional breeding involved the transfer of numerous genes from one generation to the next, including the genes for the beneficial trait as well as the undesirable traits. It then took years of self-breeding and selecting to get a plant with both the normal characteristics as well as the beneficial trait desired.

The advent of genetic engineering greatly enhanced this process of transferring a beneficial trait into plants by directly transferring the gene/s responsible for the beneficial attribute. So in one generation, or one planting season, a plant can be created that is the same in all respects except the addition of the beneficial trait. Since genes in all living organisms code for similar proteins and properties, it is possible to transfer a gene from, say, one good corn variety to another corn variety or from fish to strawberry plants.

We can now define a genetically modified organism: It is any organism that has been modified by altering one or more genes by recombinant techniques. A recombinant technique is the method used to transfer a gene of interest from one organism to another. A genetically modified food therefore is any food that is produced from plants or animals that have been genetically altered using this method.

The first genetically altered plant created was a tobacco plant with resistance to antibiotics in 1983. It was almost 10 years later when the first commercial genetically altered crop, a delayed ripening tomato, "Flavr-savr", was commercially released. This was not a commercial success, however, for reasons related to production and marketing strategies. This was soon followed by the release of several crops including Roundup Ready soy and corn. Corn and soy are the two most commonly used food crops that have been genetically altered. They have been primarily altered so that the plants can resist pests, diseases or chemicals used to destroy weeds in the field. Such alterations that improve the health of the plant and potentially benefit farmers are commonly termed as input traits; that is farmers use fewer inputs to grow their crops, be it pesticide, herbicide or chemicals to prevent diseases. There are other alterations that are possible that alter the property of the oil or starch in the seeds. These are termed output traits; that is the seeds produced by the plant have altered properties either by way of improved yields, nutritional content or higher levels or quality of starch, proteins or oils.

Genetically altered foods are very prevalent, at least in the United States and the Western world. More than 60% of the foods we purchase from the supermarket today have ingredients derived from genetically modified crops. Most of these are either from corn or soybeans, which are the base for numerous ingredients manufactured for the food industry, including starch, oils, proteins and other ingredients. Despite this prevalence, a recent USDA consumer focus group survey revealed that most consumers were unaware of the use of biotechnology in foods. Furthermore, the benefits of biotechnology were viewed as skewed towards producers and manufacturers, with little benefit to the consumer. There was also skepticism related to the long-term health effects and impact on environment. It is therefore essential that we disseminate the information about the technology of genetic engineering so that we can have an informed debate on the merits and shortcomings of this technology.

Like all new technologies, the potential for applications is tremendous, although we still have to wait to accomplish these things more efficiently/economically and understand the implications of the use of such technology. Just recently scientists created a genetically altered variety of rice, termed "golden rice" with higher levels of beta-carotene, a precursor for Vitamin A. This is promising considering that rice is the staple food for more than half the population of the world which is also the highest number of people that are under- or malnourished. The future of the technology holds promise in a number of different ways;

The scope of the technology at the present time is only limited by our imagination, and its adoption must be a result of acceptance by the public at large.

Table: List of genetically modified crops and their altered traits.

Internet Information Resources

http://www.usda.gov/agencies/biotech/index.html
http://www.ift.org/resource/policy/biotechreport.shtml
http://www.scisoc.org/aacc/MEETING/Biotechsymposium00
http://www.foe.co.uk/campaigns/food_and_biotechnology/gm_food/
http://www.greenpeace.org.uk/contentlookup.cfm?SiteKeyParam=GMFoods1