Genetically Modified Organisms as a Food Source - ACS

Chapter 14

Genetically Modified Organisms as a Food Source: History, Controversy, and Hope Downloaded via CHALMERS UNIV OF TECHNOLOGY on August 25, 2019 at 18:15:24 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.

Patrick L. Daubenmire* Department of Chemistry & Biochemistry, Loyola University Chicago, Chicago, Illinois 60660, United States *E-mail: [email protected].

Chances are you have consumed a genetically modified organism (GMO) or at least the product of one. At the turn of the 21st century, more than 100 million acres of agricultural land in the United States were seeded with GMOs and over 90% of the strains of corn and soybeans planted were genetically modified. This chapter shares some brief information about the history of GMOs and discusses the controversial aspects of their use and applications.

Early Food Cultivation Maybe it is a bit ironic, but climate changes that occurred some 10,000 years ago provided the appropriate conditions for early humans to begin cultivating food. An increasing number of humans placed depleting pressures on wild food sources. This drove the need to grow food instead of finding and capturing it. The climate changes also provided conditions that led to the natural selection of traits in plants that could withstand extremes in environmental conditions, surviving in dry times and sprouting in wet times. Such changing conditions allowed for domestication, partly because humans could selectively breed for traits that improved the endurance of crops. Agriculture was born. Fast-forward to the green revolution of the 1950s and 1960s and we can see how the combination of chemical technology with high-yield crops produced more food than was thought possible. The Haber–Bosch process provided more readily available (fixed) nitrogen that plants desperately needed. Food growth boomed and many third world countries overcame food deficits. However, there were consequences, too. Hunger still persisted. Crop monocultures, which diminished species diversity, began to dominate. By attempting to ensure sufficient nutrient availability, lands were overfertilized, which led to threats not only to crops but to entire ecosystems. The question of how and how much to use the advances of science and technology to solve our food problems was laid bare. For more on the history of agriculture, please see Chapter 3 in this volume by Sarkadi, “Impact of Agriculture on Food Supply: A History.”

© 2019 American Chemical Society

Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Genetic Modification We have known for some time that inside each living cell is a guidebook known collectively as a genome. The genome is divided into short sections of chemical codes that provide instructions governing specific reactions or processes in the cell. These sections of code are the basic units of heredity, known as genes. These genes are housed in long molecular strands called DNA and dictate the traits and characteristics that are expressed in organisms. With each replication, this information gets passed on cell to cell, generation to generation. If a gene changes, traits change and the altered information is passed along to the next generations. From a crop standpoint, traits that support robust and sustainable growth are desirable. Such crops also need to contain nutrients and taste good. Our ancestors were well aware of this, too. Although they did not have the technology to genetically alter organisms, they did have the wherewithal to selectively breed crops for desired traits. This led to at least one critical food transformation, that of a measly grass with small kernels into a crop with large stalks and ears that we call corn. Thousands of years have passed, and technology has advanced to the point where we can now intentionally alter and engineer genes. Genetically modified organisms (GMOs) are the result of humans directly manipulating genes in a laboratory, generally by inserting a gene into the host organism’s genome to express a trait not normally expressed by that organism. The first genetically engineered organism, an antibioticresistant bacterium, is credited to Hebert Boyer and Stanley Cohen in 1973 (1). It was expected that more engineering would follow and the technology would expand. As with other scientific and technological opportunities, ethical quandaries quickly arose around recombinant, or altered, DNA—man’s engineered recipes for gene expression. The Asilomar Conference on Recombinant DNA convened in 1975 gathered scientists and medical doctors to set the protocols and practices for genetic modification and manipulation (2). For example, guidelines were established to create biological barriers that would limit the spread of changed genes. This often meant using a bacterium in the experimental phase that could not survive in a natural setting. The members of that conference concluded that there is significant risk in altering the DNA of one organism with that of another because there can be unknown consequences. The protocols set at that conference remain the standard for working with genetic manipulation and are still in use at the National Institutes of Health. Sustained use of protocols does not mean the ethical debates surrounding genetic modification are closed. Ongoing, advancing technology has led to refined processes and has increased accessibility and ease for making changes in genes. Ethical reflection must keep pace so that issues of benefits and risks to the welfare of organisms and ecologies are properly addressed before and during the applications of modification (3). These issues include who or what benefits from using GMOs, how GMOs are regulated, how decisions about research on GMOs are made, and who makes those decisions. Many areas for genetic modification have since emerged. GMOs are being used to provide a variety of new products and alter reactions that are greener. In medicine, altered bacteria produce insulin, which means it does not have to be harvested from bovine sources. Changes to tobacco plants promote syntheses of a variety of pharmaceutical chemicals. GMO enzymes improve the atom economy of reactions for making Lipitor, which diminishes byproducts and waste. Other organisms have been engineered to make biodegradable bioplastics. Genetically modified algae and other plants now can produce biofuels. These are just a few examples of what GMO technology has accomplished. 204 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Genetic Modification of Food Genetic engineering might make sense to provide better or more available medicines, such as insulin, or to grow special bacteria that take in oil spills or spit out biopetrol. Why, though, mess with our food? The answer is simple and rather obvious: to strengthen the life cycles and yields of our food. That is, we need to help crops grow in sometimes austere conditions or be able to better battle pests that consume them before they get to our plates. We are a population of 7 billion, likely growing to 9 billion before mid-century. Food yields and security are certainly among the critical issues in sustaining that many people. Enhancing the durability and yields of our food through genetic modification is arguably a strategy to address the needs of this population size. Scientists have worked on food modifications for a few decades. Flavr Savr tomatoes were the first GMO to be approved by the U.S. Food and Drug Administration. They became available in 1994 with slower ripening and enhanced flavor traits. They were marketed as premium produce, which caused them to be economically unviable. They faded away, but their genes did make their way into other tomato crops (4). Papaya and rice were the next organisms to be genetically modified commercially. Creating a GMO papaya plant that was resistant to the papaya ringspot virus helped successfully maintain the viability of the crop. The modified papaya became resistant to the virus and the papaya plants could thrive. By doing so, a critical economy for Hawaiian farmers was also saved (5). Another example of modifying a food to address a need was Golden Rice. In impoverished communities across the world, poor nutrition is real and deficiency in vitamin A can be high. Industries genetically engineered rice to contain beta carotene, which humans use to synthesize vitamin A in the body. The grain’s light yellow color, due to the presence of beta carotene, gave it the name Golden Rice. According to a Time Magazine headline in 2000, “This Rice Could Save a Million Kids a Year (6).” However, at the same time, the controversy about the long-term effects and impacts of using GMOs grew. This controversy brought challenges and even protests to the widespread use of Golden Rice.

The Great GMO Debate (7) I have often told my students that chemistry is a human endeavor that lies in the tension between harming and enhancing life. The technology used to genetically modify organisms does not escape that claim. Inherent good or bad does not exist in scientific or technological discoveries. That judgment ultimately comes with the human application and management of the technology. Most of the scientific community, at least from an ethical standpoint, agrees that we, at minimum, should do no harm with the applications of the technologies. Harm, though, is a difficult concept and comes with many complex variables, especially when analyzing ecosystems and communities of organisms that interact. There are usually consequences somewhere when changes are made. The question remains: are these consequences damaging and, if so, who or what is damaged? That is not just from the perspective of treatment of other human beings but also with respect to treatment of other organisms, ecosystems, and resources on this planet. GMOs have now collided with this issue. One concern is with respect to propagating resistance. Many GMOs have been engineered to be resistant to virus attacks or herbicides. When nature interacts with plants (or GMOs) with these engineered traits, these traits can be replicated and transferred to other organisms through reproduction cycles. This means an engineered trait can be passed along and possibly across species. If so, the trait gets propagated.

205 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

Our engineering does not stop nature’s pathways; rather, it engages with them. Even though we engineer in a lab, organisms in nature still mutate, adapt, and reproduce. Thus, in the late 20th and early 21st century, when organisms were discovered that were resistant to the herbicide glyphosate, other concerns about using GMOs elevated. Continuing in the 21st century, larger issues arose with the Bacillus thuringiensis toxin that had been engineered into cotton crops to ward off pests. Caterpillars were discovered that were immune to the toxin, and the toxin itself had been discovered in the blood of pregnant women and their fetuses. The debate about the utility and safety of GMOs escalated to a roaring crescendo. As a result, GMOs take their place in the tension between harming and enhancing life. Here are some other issues in the current debate. Genetic Engineering Is Not Natural Some people think that transgenic manipulation, the insertion of DNA pieces from a different species into a plant’s DNA, interferes with nature and unduly alters its processes. Some further argue that the transfer of genes in this way is beyond the role of humans in this world. The introduction of foreign DNA into a plant’s genome actually mimics natural processes. In fact, recent research discovered that bacteria—similar to those that genetic engineers use to modify corn with the B. thuringiensis gene—inserted its own bacterial DNA into sweet potatoes in South America at least 8000 years ago. The normal plant root became swollen with starch and was integrated into the diet of early Native Americans. Now, several varieties of sweet potato exist throughout the world, and it is the world’s seventh most important staple crop. It is the primary source of calories for millions of people. The exchange of DNA across species is not a rare event and most typically occurs in single-celled organisms such as bacteria. Gene transfer has also occurred between millet and rice (8, 9). GMOs Cause Health Problems Such as Allergies and Cancer There is some concern that genetic engineering will introduce dangerous compounds, such as allergens or toxins, into the food chain. Some of these compounds may be carcinogenic and could lead to tumors in those who eat the GMO. While it is possible for a new gene to express a protein that is an allergen or toxin, research scientists work with food regulators and rigorously test their creations for toxicity. For example, in 1996, a company that was trying to insert a beneficial Brazil nut gene into soybeans halted the project when it was discovered that the resulting soybeans also carried a nut allergen. While the majority of testing data is treated as proprietary information by biotech companies and not released to the public, thousands of published safety reports on GMOs have shown no evidence that the foods are more dangerous than non-GMOs. Over 10 years of scientific research has yet to find significant hazards directly connected to the use of GMOs (10, 11, 12). This, of course, does not mean that they do not exist. GMOs Cause Farmers To Over-Use Pesticides and Herbicides GMO opponents often point out that farmers growing genetically engineered crops have increased the amount of pesticides or herbicides used to protect their crops. One type of corn, for example, is genetically engineered to be resistant to a type of herbicide called glyphosate. The use of glyphosate has dramatically increased since the introduction of this type of corn. Some types of crops have been developed that actually reduce reliance on pesticides. A case in point is the B. thuringiensis corn described earlier in this chapter. The plant itself grows its own 206 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

pesticide—one that is specific to insects and does not interact with the biology of other animals—in levels much lower than that required to treat the outside surface of the plant. As for glyphosate, its increased use has led to the decrease in use of other herbicides that are more toxic (13, 14). The application of glyphosate typically calls for 360 mL/acre, or about a soda can’s worth of herbicide for about 43,500 ft2. To put this in perspective, an American football field (excluding the end zones) is 48,000 ft2. If the plant is growing its own pesticide, no additional amount needs to be applied. GMOs Create “Super Insects” and “Super Weeds” In the ecosystem surrounding a genetically modified crop, the targeted weeds, bugs, or bacteria must move, die, or evolve. If the species evolves, the genetically modified crop may have no resistance to it. Historically, we solved the problem of the evolution of a pest by finding a natural trait within the existing crop varieties and then using selective breeding to create a new, stronger hybrid. As we come to depend on a narrower set of crop varieties, we no longer have the genetic variety for such selection. Regulators in both the United States and the European Union require the cultivation of traditional crops, without engineered toxins or resistance traits, alongside genetically modified varieties. The mix is intended to prevent evolution of resistance in pests because resistance to the crop will not be a survival requirement. Scientists may need to further test how much of the nonengineered crop is enough to minimize the risk of newly resistant pests. As engineered crops become more widespread, more research needs to be done with respect to their intended and unintended impacts. Such research needs to be honest about biases which may exist and which questions may remain unanswered (15). For more on the history of agriculture, please see Chapter 9 in this volume by Sarkadi, “Effects of Fertilizer on Food Supply.” Farmers Cannot Replant Genetically Modified Seeds A claim has been made that some seed companies use what is called a “terminator gene” to prevent GMO crop seeds from being able to be replanted. There have been no crops developed that incorporate this technology. Seed companies often do, however, require agreements that prevent farmers from replanting seeds gathered from a GMO crop, ensuring future purchases of new seeds every year. Before the advent of genetic engineering, most of the corn crops grown in the United States and the European Union were commercially developed hybrids that led to a mixture of inferior corn variants with lower yields when replanted. Beginning in the 1930s, seed companies began developing high-yield hybrid corn and by 1965, 95% of the corn crops planted in the United States were hybrids requiring planting of newly purchased seeds to keep yields high. Although this trend started with corn hybrids, farmers growing other crops also began to repurchase new seeds rather than replant saved seeds. Today, even farmers not using GMOs prefer to purchase new seeds every year to ensure higher yields in their harvests. There are many arguments back and forth over the use and safety of GMOs. They have been put forth as a way to increase crop yields but advocacy groups against GMOs claim they have failed to do so (16). Because of the potential threat to human and environmental health as well as the concern that GMOs reduce plant diversity, several European nations have banned GMOs altogether. Other countries require foods with GMOs to be labeled accordingly so that consumers are informed of what they are eating and what its sources are. The United States will also enforce such a requirement beginning in 2020. Other advocacy groups that support the use of GMOs point to scientific evidence. GMOs have not been shown to be harmful and unsafe to eat (17).

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Valid claims are made on both sides, but these claims are also interwoven with advocacy, political viewpoints, and the influence of business and industry (18). In this ongoing debate, as with any application of scientific processes, astute study and ethical reasoning must continue to be jointly employed when making decisions about the use of GMOs.

Hope: Addressing World Needs The United Nations has set 17 Sustainable Development Goals to ensure the world remains a viable place for all peoples, generations, and environments (19). At least six directly relate to the growth, availability, and consumption of food. As our population climbs to 10 billion people, the issue of how to feed us will not recede. Finding solutions is tantamount to our survival. The intelligence, tools, and devices that have aided our evolution as a species cannot be ignored in the quest to keep it on this planet. Our scientific and technological developments are necessary to find these solutions. Hunger and malnutrition affect every aspect of human development and persist for various reasons including unequal access to land, to sufficient and nutritious food, and to other productive resources. Adequate food production is necessary but insufficient to ensure national nutritional security. . . So the challenge for agriculture is three-fold: to increase agricultural production, especially of nutrient-rich foods, to do so in ways which reduce inequality, and to reverse and prevent resource degradation. [Science and Technology] can play a vital role in meeting these challenges. - Zareen Pervez Bharucha (20) Although the debate rages on, the history of GMOs appears to continue as they remain likely players in forging solutions to feeding this world. They alone are not the solution, but for now, they appear to have a seat at the table. They are joined by others such as sustainable farming, agroecology principles and practices, and innovations for farmers of small lands. The cautions and pauses associated with the use of GMOs must continue to be considered. Together, we cannot lose sight of the vision of our American Chemical Society: to improve people’s lives through the transforming power of chemistry! GMOs, as debated as they as, are chemical tools we have for potentially transforming food into a sustainable resource for this planet.

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Rangel, G. From Corgis to Corn: A Brief Look at the Long History of GMO Technology, 2015. Science in the News Blog, Harvard University Graduate School for the Arts and Sciences Web site. http://sitn.hms.harvard.edu/flash/2015/from-corgis-to-corn-a-brief-look-at-the-longhistory-of-gmo-technology/ (accessed Oct 26, 2018). Berg, P.; Baltimore, D.; Brenner, S.; Roblin, R. O.; Singer, M. F. Summary Statement of the Asilomar Conference on Recombinant DNA Molecules. Proc. Natl. Acad. Sci. U.S.A 1975June. Rodriguez, E. Ethical Issues in Genome Editing for Non-Human Organisms Using CRISPR/ Cas9 System. J. Clin. Res. Bioeth. 2017, 8, 300. American Chemical Society. Chem. Eng. News 1999, 77, 27. Smyth, S. How GM Papaya Saved Hawaii’s Papaya Industry, 2015. SAIFood Web site. https://saifood.ca/gm-papaya/ (accessed Oct 26, 2018). Nash, J. M. This Rice Could Save a Million Kids a Year. Time Magazine 2000July31. 208 Orna et al.; Chemistry’s Role in Food Production and Sustainability: Past and Present ACS Symposium Series; American Chemical Society: Washington, DC, 2019.

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Much of the source material for this section comes from Fahlman, B., ed. (2017). Chemistry in Context, 9th edition. American Chemical Society. Diao, X.; Freeling, M.; Lisch, D. Horizontal Transfer of a Plant Transposon. PLoS Biol. 2005, 4, e5. Kyndt, T.; Quispe, D.; Zhai, H.; Jarret, R.; Ghislain, M.; Liu, Q.; Gheysen, G.; Kreuze, J. F. Sweet Potato: A Naturally Transgenic Food Crop. Proc. Natl. Acad. Sci. U.S.A. 2015, 112, 5844–5849. Goodman, R. E.; Vieths, S.; Sampson, H. A.; Hill, D.; Ebisawa, M.; Taylor, S. L.; van Ree, R. Allergenicity Assessment of Genetically Modified Crops—What Makes Sense? Nat. Biotechnol. 2008, 26, 73–81. Lehrer, S. B.; Bannon, G. A. Risks of Allergic Reactions to Biotech Proteins in Foods: Perception and Reality. Allergy 2005, 60, 559–564. Nicolia, A.; Manzo, A.; Veronesi, F.; Rosellini, D. An Overview of the Last 10 Years of Genetically Engineered Crop Safety Research. Crit. Rev. Biotech. 2014, 32. Benbrook, C. M. Impacts of Genetically Engineered Crops on Pesticide Use in the U.S.—the first sixteen years. Environ. Sci. Eur. 2012. Ferrell, J. A.; Witt, W. W. Comparison of Glyphosate with Other Herbicides for Weed Control in Corn (Zea mays): Efficacy and Economics. Weed Technol. 2002, 16, 701–706. Bakhsh, A.; Khabbazi, S. D.; Baloch, F. S.; Demirel, U.; Caliskan, M. E; Hatipoglu, R.; Ozcan, S.; Ozcan, H. Insect-Resistant Transgenic Crops: Retrospect and Challenges. Turk J. Agric. For. 2015, 39, 531–548. Gurian-Sherman, D. Failure to Yield: Evaluating the Performance of Genetically Engineered Crops; Union of Concerned Scientists: Cambridge, MA, April 2009. https://www.ucsusa.org/sites/ default/files/legacy/assets/documents/foodandagriculture/failure-to-yield.pdf (accessed Dec 5, 2018). National Academies of Sciences, Engineering, and Medicine. Genetically Engineered Crops: Experiences and Prospects. The National Academies Press: Washington, DC, 2016. Zhang, C.; Wohlhueter, R.; Zhang, H. Genetically Modified Foods: A Critical Review of Their Promise and Problems. Food Science and Human Wellness 2016, 5, 116–123. United Natons. Sustainable Development Goals. https://www.un.org/sustainabledevelopment/ sustainable-development-goals/ (accessed Oct 15, 2018). Bharucha, Z. P. Sustainable Food Production: Past and Present, 2013. SciDiv.net. https://www. scidev.net/global/food-security/feature/sustainable-food-production-facts-and-figures.html (accessed Dec 5, 2018).

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