GMOs: Applications and Controversy

Introduction

Genetically modified organisms, or GMOs, are a hot topic in societal health and diet. Are genetically modified (GM) foods safe to eat? Ethical to produce? What does it even mean to be a GMO? Genetic engineering includes molecular techniques that target the genome of an organism and alter it in some way. This could mean turning off genes, enhancing the activity of genes, or introducing new genes to the genome—genes that could be from the same species or a completely different species as the organism. The goal of this modification to the genome is to create an organism that expresses a desired trait. This genetically altered organism will be considered a GMO, and this article will cover the ways and reasons these GMOs have typically been modified.

Genetic engineering (GE) is a tool impacting millions of lives. GMOs impact the families and societies that eat them, the farmers that cultivate them, and the scientists who design them. This article will demystify GMOs and answer common burning questions about them.

What are genetic engineering (GE) techniques? How do they work?

How GE generally works is that a gene from one organism is delivered to the cells of another organism using a vector, such as a plasmid or virus (Kisseadoo, 2024). While animals may be genetically modified, the GMOs discussed in this article will focus primarily on transgenic plants. When transformation through vectors is not possible, scientists may also use methods such as “particle bombardment, microinjection, and electroporation” (Kisseadoo, 2024). GE is dependent on getting DNA past the cell wall of the plant so it can be used by the cell, and the cell expressing the new gene how the scientist intended. Some other GE techniques include “Zinc Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs), and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas system” (Aziz et al., 2022). CRISPR, a relatively new technique, is unique in that it does not require the introduced genetic material to be from unrelated species (Teferra, 2021).

Why make GMOs?

Growing crops comes with a list of possible problems: crop disease, insect pests, weeds, natural disasters, difficult climate, spoilage, and more. An example of how GE could prevent crop depredation by insects provided by Dr. Kisseadoo in his article “Agricultural Applications Of Genetic Engineering” was the garden pea: by introducing genes that “prevent the digestion of starch by two insect pests, the cowpea weevil and Azuki bean weevil” that originated from common bean plants, garden peas could also express this gene to ward off pests (Kisseadoo 2024). The first GM crop to be Food and Drug Administration (FDA) approved was the Flavr Sav tomato, which was modified to decrease the production of the enzyme polygalacturonase, effectively delaying spoilage and extending the shelf life for the tomatoes (Aziz et al., 2022).

GMOs have allowed for greater food production, which is valuable for humanity’s growing population. Modification of plants to grow in harsher environments means communities that never had the opportunity to grow the crops for themselves due to conditions that were possibly too hot, too cold, too dry, too moist, etc. now can (Kissadoo 2024). Furthermore, the introduction of genes related to the production of particular vitamins or nutrients to GM food has also allowed communities otherwise deprived of these vitamins and nutrients to become healthy. For example, the genetic modification of rice to enable the production of beta-carotenes provided communities the vitamin A needed to prevent blindness in children (Teferra, 2021).

Are there alternatives to GMOs?

Strategies alternative to genetic engineering include selective breeding and artificial selection; strategies that still affect the gene content of resulting organisms. These strategies involve recognizing individuals of a species with desired traits and attempting to breed the individuals to produce offspring that possess the desired traits (Aziz et al., 2022). The downside of these traditional strategies is that they do not possess the same level of specificity that modifying organisms using molecular tools allows. While GE allows scientists to select specific genes to target or introduce to genomes, selective breeding offers no control over whether unwanted genes are passed to offspring alongside desired genes (Datta, 2013). An article from the journal Agriculture & Food Security provides an example of the consequences of this: “Potato varieties developed using traditional breeding produce excessive amounts of naturally occurring glycoalkaloids. These glycoalkaloids cause alkaloid poisoning leading to gastrointestinal, circulatory, neurological and dermatological problems” (Datta, 2013). Additionally, sometimes genetic engineering is the only available solution to problems threatening crop cultivation, which is, for example, the case with treatment of the papaya ringspot virus in papayas (Datta, 2013).

Are GMOs safe for humans? How about the environment?

It is possible for GM food to contain allergens. An article from Frontiers in Science describes how an attempt to make soybeans more nutritious involved the transference of methionine-rich 2S albumin to transgenic soybeans from a Brazil nut, a food known to cause allergic reactions, and which consequently led to the soybean presenting a risk as an allergenic food as well (Aziz et al., 2022). Another well-cited example is “Starlink” maize, which was modified to include a gene that would improve insect resistance, but this gene also increased the allergenicity of the crop (Zhang et al., 2016). The solution to worries of allergenicity is to conduct biosafety testing on every GM product before it ever enters the market— for example, by investigating the effect of the GM product in mouse models first. Fortunately, allergen data is available and can be referenced before drawing genes from foods that commonly are responsible for allergic reactions and introducing GM products that contain these genes to the public (Bawa & Anilakumar, 2012). Genetically engineered food is still relatively new and requires long-term investigation of its health effects on humans, but thankfully, “To date there is no solid evidence that GM crops approved in the US and other countries have harmed humans or animals that had consumed them” (Aziz et al., 2022).

One might also be concerned about what pleiotropic effects modification to crop genomes could have. To put this in other words, you may worry that the modification of a gene will impact the expression of physical traits unrelated to the trait of interest, but which happen to be linked to the same gene as the trait of interest. Unfortunately, these effects are difficult to study because, as Zhang et al. put it, “Connecting the causative dots presupposes an intimate understanding of the biochemical and regulatory pathways – which may be beyond current comprehension” (Zhang et al., 2016). Pleiotropic effects are worth considering for most crops, whether the crop was produced through traditional breeding methods or genetic engineering.

The development of antibiotic resistance in human gut bacteria is a concern voiced by scientists, though it is an event of low occurrence; the thought behind this worry is that antibiotic resistance genes found in GM plants might be transferred to human gut bacteria through horizontal gene transfer (Aziz et al., 2022). Ideally, bacteria would not be resistant to our antibiotics, particularly pathogenic bacteria, which is why this worry exists. In a similar vein, there exist concerns that herbicide and pest resistance genes in GM crops might promote the evolution of superweeds and pests that are able to overcome these barriers (Bawa & Anilakumar, 2012). This would then require the usage of increased doses of herbicides and insecticides on crops. There is also the fear of “genetic pollution”, or the pollen of GM crops spreading to non-GM crops and leading to a decrease in biodiversity; by knowing how far pollen will travel, however, this fear can be managed by careful spacing of GM fields away from non-GM crops to minimize unintended gene flow (Aziz et al., 2022).

With all of this in mind, GM products can also be seen as a more sustainable form of agriculture. Dr. Raman notes that “while increasing global yield by 22%, GM crops reduced pesticide (active ingredient) usage by 37% and environmental impact (insecticide and herbicide use) by 18%” (Raman, 2017). By minimizing the application of chemicals applied to crops, GM crops help minimize the harmful off-target effects caused by these chemicals.

I’m still afraid of GMOs being used unethically…

While GMOs are generally safe for humans and the environment, it is worthwhile to consider implications of patenting GM seeds, and how these patents may be used unethically. Companies that design seeds that achieve a particular trait can patent this design to obtain credit and authority over its distribution. Aziz et al. note that “The patent rights provide monopoly power to the seed companies, which require the farmers to purchase the seeds from the patent owners during each year of plantation” (Aziz et al., 2022). The development of “terminator seeds” that produce infertile crops with infertile pollen is a situation that may lead some to deem the treatment of GM seeds as the intellectual property of the GM seed producers as unethical; keep in mind however, that, “There are also very few farmers that depend on second-generation seeds. Hence, the introduction of sterile seeds does not affect the farmer's seed choice” (Aziz et al., 2022).

Fear and misconceptions about GMOs have led to cases of extreme regulation of GMOs by governments. As Aziz et al. put it: “Specifically, the majority of European and Middle Eastern countries have imposed full or partial limitations on the commercialization of GM crops. Regulatory approval for the commercialization of GM crops is hampered by poor communication and awareness brought about by consumer mistrust” (Aziz et al., 2022). While monitoring or regulating can help ensure GE technology is being used with public health and the environment's best interests in mind and with no unintended consequences, strict banning of GMOs is unnecessary and an impractical choice for “protecting” public health. If your fear is that this technology will be used unethically or cause serious harm, know that governments have this fear too— but theirs is a fear born from lack of communication with the scientific community. You, at the very least, have read this article.

Conclusion

Genetic engineering in agriculture allows humans to overcome problems that would take years of selective breeding and cost many more lives if the technology were not available. Public perception of GMOs is one of fear, skepticism, and worry, and something that should be addressed by both the scientific community, governments, and the general public. Scientists and companies should ask whether they are using GE ethically and what unwanted consequences their products could bring. Governments should assess whether banning GM foods is a productive action to protect public health. The general public should question their assumptions, clarify their worries, and reflect whether specific genetic modifications —for example, modifications for crop disease resistance vs. modifications for flavor or nutrient content— align or betray their interests as consumers.

The field of genetic engineering is still being expanded upon, for as an article from Frontiers in Plant Science states, “applications of GMOs are diverse and include drugs in food, bananas that produce human vaccines against infectious diseases such as Hepatitis B (Kumar et al. 2005), metabolically engineered fish that mature more quickly, fruit and nut trees that yield years earlier, foods no longer containing properties associated with common intolerances, and plants that produce new biodegradable plastics with unique properties” (Aziz et al., 2022). Genetic engineering may reach heights human society never anticipated— and will therefore continue to invite controversy and debate. The responsible action is to minimize off-target effects and ensure this technology is being used safely.

Sources Cited

Aziz, M. A., Brini, F., Rouached, H., & Masmoudi, K. (2022). Genetically Engineered Crops For Sustainably Enhanced Food Production Systems. Frontiers in Plant Science, 13, 1027828. https://doi.org/10.3389/fpls.2022.1027828

Bawa, A. S., & Anilakumar, K. R. (2012). Genetically Modified Foods: Safety, Risks And Public Concerns—A Review. Journal of Food Science and Technology, 50(6), 1035–1046. https://doi.org/10.1007/s13197-012-0899-1

Datta, A. (2013). Genetic Engineering For Improving Quality And Productivity Of Crops. Agriculture & Food Security, 2(1). https://doi.org/10.1186/2048-7010-2-15

Kisseadoo, S. (2024). Agricultural Applications of Genetic Engineering. EBSCO. https://www.ebsco.com/research-starters/agriculture-and-agribusiness/agricultural-applications-genetic-engineering

Raman, R. (2017). The Impact Of Genetically Modified (Gm) Crops In Modern Agriculture: A Review. GM Crops & Food, 8(4), 195–208. https://doi.org/10.1080/21645698.2017.1413522

Teferra, T. F. (2021). Should We Still Worry About The Safety Of Gmo Foods? Why And Why Not? A Review. Food Science & Nutrition, 9(9), 5324–5331. https://doi.org/10.1002/fsn3.2499

Zhang, C., Wohlhueter, R., & Zhang, H. (2016). Genetically Modified Foods: A Critical Review Of Their Promise And Problems. Food Science and Human Wellness, 5(3), 116–123. https://doi.org/10.1016/j.fshw.2016.04.002