Genetically modified organisms, or GMOs, are plants and animals in which the genetic material has been artificially altered through technological means. Genetic modification is now so widespread in agriculture that most Americans consume GMO-derived food every day without even realizing it (Chrispeels, 2014). Genetically modified meats, fruits, and vegetables are made by extracting and splicing segments of DNA from different organisms together.
How GMOS are Created
The creation of GMOs requires three main components: the gene to be transferred, the organism that the gene will be transferred into, and the vector of transmission that will deliver the new gene to the host, or target, cell (HAIB, 2008). This process allows select genes from similar species, and even genes from unrelated species, to be recombined. Though the steps involved in engineering genetically modified organisms may be simple and straightforward, the process can be challenging from a technical standpoint. The gene to be transferred into the host organism has to be cut out of the original organism using restriction enzymes. Restriction enzymes act like scissors within the molecule, identifying specific nucleotide sequences and cleaving them out of the DNA strand. Restriction endonucleases (RE) are generally extracted from bacteria, and thousands of REs have been isolated for use in genetic engineering.
After the restriction enzyme has located and cut out the gene to be transferred (the trans-gene), the trans-gene is ready to be inserted into the cell of the target species using a virus as a vector of transmission. This is accomplished by removing the part of the viral genome that causes harm, while leaving the part that allows the virus to get into host cells intact. Once the trans-gene has been inserted into the vector, the vector is inserted into the host cells. When it is inside the host cell, the trans-gene combines with the genome of the host. When the host cells replicate, they create copies that contain part of the genome of the original organism.
The Purpose of Genetic Engineering
Genetically modified organisms have been produced in order to improve the quality and durability of food for human consumption. Genetically modified crops have been engineered to have greater resilience to pests and fungal and bacterial contamination, and to have greater nutritional value. Plants have also been genetically modified to have increased tolerance to herbicides. Genetic engineering of crops has had the dual advantage of creating more nutritious fruits and vegetables at a lower cost, since by reducing the amount of crops that fall to disease, the expense of farming is decreased, and the value is passed on to consumers.
For example, some crops have been genetically modified to be more resistant to insects by the incorporation of a gene from the bacterium Bacillus thuringiensis (WHO, 2015). The gene is safe for human consumption and can be conventionally used as an insecticide. Crops that have inherited this gene from genetic modification generally need lower quantities of other insecticides.
Which Foods Contain GMOs?
Many of the food products found in America's grocery stores are derived from genetically modified organisms. The GMO crops that are widely grown and consumed as food include corn, soybeans, canola (oilseed rape), and sugar beets (Chrispeels, 2014). Although there are several starchy crops on the market that are genetically modified, most stores do not sell genetically modified fruits or vegetables. However, packaged goods that contain any of the four mentioned crop groups will generally also contain GM ingredients. For example, high fructose corn syrup is a common ingredient in many prepackaged goods, and it is derived from genetically modified maize, or corn. Most sodas, cookies, cakes, and breads for sale from American vendors will have genetically modified corn as one of the ingredients. In total, approximately seventy percent of the prepackaged, frozen, and bottled foods for sale in grocery stores contain GM ingredients, and these products can vary in proportion that is GM from 1 to 100 percent (Chrispeels, 2014).
The Safety of Genetically Modified Foods
The World Health Organization considers genetically modified foods to be as safe as non-genetically modified foods (WHO, 2015). Rigorous systems of evaluation have been instituted to assess the safety risks of genetically modified foods and organisms, both to human health and to the environment. Conventional foods are not subject to the same investigation, so it can be said that GM foods are held to a higher standard of safety than non-GM foods.
The assessment of GM foods is conducted on multiple levels. First, researchers focus on the direct impact on health; second, on the potential to induce an allergic reaction; third, the stability of the transferred gene; fourth, effects on the nutritional value; and fifth, the unintended consequences, if any, of gene insertion. After the different aspects of the safety of the GM food are verified, the product is cleared for sale.
The way genetically modified foods are regulated varies from country to country (Chrispeels, 2014). In the United States, the regulation of GM foods mostly emphasizes the implementation of evaluations to ensure the safety of the foods before they enter the market. The legislation regarding the sale of GM foods is constantly evolving as more advancements are made in the technologies that are use to genetically engineer our food.
Chrispeels, M. J. (2014). Yes indeed, most Americans do eat GMOs every day!. Journal of integrative plant biology, 56(1), 4-6.
HudsonAlpha Institute for Biotechnology. (2008). “How Are GMOs Made?” Retrieved from http://archive.hudsonalpha.org/education/kits/gmod/gmos-made
Wang, K. (2012). Should we promote the widespread consumption of biotech foods. Young Scientists Journal, 5(12), 77.
World Health Organization. (2015). “Frequently asked questions on genetically modified foods.” Retrieved from http://www.who.int/foodsafety/areas_work/food-technology/faq- genetically-modified-food/en/