An Exploration of Genetically Modified Zea mays, its Production, and Effects. John Fierst. Abstract

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1 An Exploration of Genetically Modified Zea mays, its Production, and Effects John Fierst Abstract This paper will examine the procedure for creating a genetically modified corn plant, its uses in both farming and in food products, its nutritional and health effects, and its social implications. A genetically modified organism is an organism that contains a transgene, which was taken up by the organism after a series of procedures involving modern recombinant DNA technology. This genetic modification in Z. mays typically includes a Bt gene that provides resistance to insects, as well as a gene or genes that provide resistance to herbicides. Genetic modification of a crop can be very beneficial, often resulting in higher yields and less use of pesticide and herbicide. Genetically modified crops, including Z. mays, are now widely used not only in the United States, but also around the world. Many livestock feeds are made from genetically modified corn, and its nutritional viability is essentially the same as its nongenetically modified counterpart. The general scientific consensus is that genetically modified crops and food products pose no hazard to human health, although there are examples of studies that suggest otherwise. There are a number of social implications that the existence of genetically modified crops bring about, including doubt and a perception of risk in the general public of consuming food that has been genetically modified; there has been debate about product labelling, with some consumers demanding that genetically modified food products be labelled. Modern recombinant DNA biotechnology has already proven its benefits to our society, and it can be expected that continued use of biotechnology such as genetic modification will hold great promise for bettering mankind.

2 John Fierst Dr. John Watson Biology Capstone, BIOL-K490 8 May 2014 An Exploration of Genetically Modified Zea mays, its Production, and Effects Introduction Genetically modified foods have become commonplace on today s grocery store shelves. Many people see genetically modified or GMO and immediately think that these foods pose a health risk to them. What is a genetically modified organism, or GMO? A genetically modified organism is an organism that contains a transgene, or a gene from a different organism or from an artificial source. This genetic modification is part of modern recombinant DNA technology. (Griffiths) One organism that is commonly genetically modified is Zea mays, also known as corn or maize. Corn is an important crop in the United States, and as its origin is the Americas, it grows abundantly. As the demand for food production continues to grow all around the world, ways to improve the yield of corn have been sought; one of those ways is through the creation of a genetically modified Z. mays crop. This paper will examine the procedure for creating a genetically modified corn plant, applications of genetic modification in Z. mays, this crop s uses in both farming and in food products, its nutritional and health effects, and its social implications. Creation of Genetically Modified Corn The creation of a genetically modified organism begins not in that organism itself, but rather in the cells of the organism that will supply the transgene or in the research lab where a

3 completely new gene can be engineered. The transgene is the gene that will be integrated into the genome of the soon-to-be genetically modified maize. There are a number of reasons why transferring a gene from one organism to another or creating a new gene would be beneficial. In the case of agriculture, a gene may provide resistance to an herbicide or resistance to a predatory insect or worm. Another use of recombinant DNA technology is gene therapy, or the introduction of a functional gene into the genome of an individual who lacks a functional allele of an essential gene. By using recombinant DNA technology for any of these reasons, both directly in human applications and through applications in other species, improvements in today s society can be achieved. Once the transgene is isolated, it is cut out of the strand of DNA by the use of restriction enzymes. A restriction enzyme is a protein that cuts the strand of DNA at a recognized sequence of base pairs. A number of useful restriction enzymes commonly used for research purposes are isolated from bacteria, such as EcoRI. The isolated transgene is then also inserted into a plasmid through the use of restriction enzymes. A plasmid is a circular ring of DNA that is used as a vector for gene transfer. Once the plasmid contains the gene of interest, it is placed in a dish with the cells of the organism that will uptake them; this uptake occurs because of a procedure that makes the cell membrane slightly permeable. This now permeable membrane will allow the gene of interest to enter into the organism s cells and be expressed. A visual summary of this process is depicted below.

4 (Griffiths, Anthony. Encyclopedia Britannica.) It is interesting to note that the process of genetic modification for Z. mays is many times not started with the corn plant itself. Rather, model organisms are often used during the preliminary stages of testing to explore whether or not a transgene works. Model organisms like the small flowering plant Arabidopsis thaliana or the tobacco plant allow research teams to test their genetic modification in a plant that is often cheaper and grows faster than Z. mays itself. (Castiglioni, et. al.) Bt corn and Insect Resistance The process of genetic modification has been explained, so next an application of this procedure will be outlined. Genetically modified corn typically has a gene for herbicide resistance and for pest or insect resistance. One very common type of maize is Bt corn which contains a gene that makes it resistant to many types of caterpillars. The Bt gene is named after

5 Bacillus thuringiensis, a bacterium that thrives not only in the soil but also on the surfaces of crop leaves and produces a genetic product that kills plant-eating worms; this genetic product essentially acts as the plant s own insecticide. There are roughly 600 strains of B. thuringiensis, and each strain s gene product is a different endotoxin that targets a different species of harmful insect or pest. (Castiglioni, et. al.) Multiple types of these genes can be introduced into the genome of Z. mays as described above, which then makes it resistant to many insects. (University of California San Diego, In the early 2000s, concern arose over Bt corn s insecticidal effects on not only the cropeating worms and caterpillars that it targeted, but on other harmless species of insects. Because Bt corn releases its genetic product into the localized environment around it, other organisms besides the corn itself and the crop-destroying insects it comes in contact with could be affected. After the introduction of Bt corn, some studies had shown that the monarch butterfly was adversely affected by the Bt corn s production of insecticide because this species of butterfly was closely related to the insects being killed by the Bt corn s insecticide. Further studies done confirmed that the monarch butterfly was not exposed to levels of the Bt corn s genetic product in high enough concentrations for it to produce significantly harmful effects on the monarch butterfly. (Peairs, The cspb Gene and Drought Resistance A typical maize crop may use nearly half a million gallons of water each season. Drought is an abiotic environmental adversity that can wreak havoc on a maize crop that requires so much water. Many corn farmers will experience at least one drought over the course of their time as farmers, and because of this, another example of an up and coming genetic modification is a gene for drought resistance. According to the BioTrack Product Database, Monsanto has

6 recently released a strain of maize that is drought resistant. This maize has the cspb gene, which was isolated from a bacterium, and it is marketed as DroughtGard TM Maize. (Organisation for Economic Cooperation and Development, %C3%98-4) The cspb gene is noted as the cold shock protein B gene, and this gene actually produces an RNA chaperone protein in bacteria during times that the bacterium is exposed to cold temperatures. Experimentation done with cspb-modified maize showed that the presence of this gene reduced kernel abortion in the plant during periods of induced drought brought on right before anthesis, or plant flowering. Not only was kernel abortion significantly reduced, but increases in rates of photosynthesis and chlorophyll levels were recorded in the leaves of the maize as well. It is important to note that the introduction of this gene into the Z. mays genome does not mean that the maize crop can be grown with little water over the entire course of its life. In fact, it must be regularly watered the same way that any other type of maize crop is watered. The key in Monsanto s engineering is that the presence of this gene would allow the maize crop to be hardy against a shock, which in this case is the shock of a period of drought. (Castiglioni, et. al.) Drought resistant genetic technologies are particularly promising because there is no second organism with which to contend; many lines of insect-resistant crops are showing signs of insect resistance. When the caterpillar or worm is no longer killed by the genetically modified corn, researchers must begin the process of creating a new transgene over again. Since drought is not another living organism, it can be said that drought resistant varieties of corn will likely need little modification in the future.

7 Agricultural Use In the year 2010, 86% of Z. mays grown in the United States was genetically modified. (National Agricultural Statistics Service) Over 20 countries grow genetically modified maize currently. Many organizations and countries have demonstrated the great benefits of cultivating genetically modified crops; one study showed that the amount of pesticide used with genetically modified maize was significantly reduced when compared to standard, non-genetically modified maize. (R.H. Phipps) Many questions were raised over the use of genetically modified feed for livestock. One review article published on the nutritional validity of genetically modified feed stated that the results available to date are reassuring and reveal no significant differences in the safety and nutritional value of feedstuffs containing material derived from the so-called 1st generation of genetically modified plants (those with unchanged gross composition) in comparison with non- GM varieties. (Gerhard Flachowsky) This same study broke down the genetically modified feed and the non-gm variety of feed and compared them for nutritional quality. The resulting data showed insignificant differences in nutritional quality. For example, the crude protein amount in isogenic maize was 120 grams per kilogram, and the crude protein amount in herbicide tolerant maize was 119 grams per kilogram. The following table was taken from this study:

8 (Gerhard Flachowsky, Animal nutrition with feeds from genetically modified plants.) Flachowsky s study also found that some genetically modified crops even proved to be more robust than their unmodified counterparts. The genetically modified soybeans used in feed contained over 15% more crude protein than the regular soybean meal. Flachowsky also notes in his research that transgenic DNA accounts for a negligible percentage ( %) of total DNA ingested and subsequently digested by the cattle. In his studies, any DNA that was ingested by the cattle was degraded before it could come in contact with Peyer s patches, which are areas of gut-associated lymphoid tissue found in the intestines. Thus, no transgenic DNA, or any genetic material, could be taken up by the cattle. (Gerhard Flachowsky) Health Effects on Humans Unfortunately, many false perceptions on the safety of genetically modified crops and food have permeated American society. The general consensus in the scientific community is that genetically modified crops pose no threat to the health or well-being of any humans. In fact,

9 genetically modified crops must undergo a very rigorous and intensive series of testing and analyses before they may be approved to go on the market for human consumption. (American Association for the Advancement of Science) Supporting these claims is a literature review done assessing 24 different long-term and multigenerational scientific studies on the health risks of diets with genetically modified foods, which found that none of these studies suggested genetically modified foods had any negative impacts on the health of humans. This literature review also echoed the work of Gerhard Flachowsky as it found that there was no nutritional imbalance between regular maize and genetically modified insect-resistant maize used agriculturally in feed for cattle. (Chelsea Snell, et. al.) On the other hand, a study published analyzed the effects of three different types of genetically modified corn (MON 810, MON 863, and NK 603) on rats. The NK 603 variety is resistant to the herbicide Roundup; MON 810 and MON 863 are Bt varieties which make them resistant to insects. Roughly 60 biological factors were tested, and the study concluded that the genetically modified corn varieties tested induce a state of hepatorenal toxicity. (Joel Spiroux de Vendomois) Even though this review of research was published by the National Institutes of Health, it is very imperative to note that Spiroux de Vendomois research has largely been discredited. Despite the overwhelming body of evidence to support the safety of genetically modified foods effects on animals, including humans, ongoing public concern will continue to fuel more research to provide the most definitive and conclusive answer to the health effects of genetically modified Z. mays.

10 Societal Implications A number of studies have been done that depict the views and opinions of the general public on food biotechnology, products that are genetically modified, and animals that were given genetically modified feed. One such study concluded that a majority of perceptions of risk largely were centered around the idea that certain perceived qualities of risk such as how much choice was able to be exercised over the use of a biotechnology, what was the benefit compared to the risk, and the anxiety about potential negative impacts on health and the environment. (Hunt) The author of this study, Lesley Hunt, noted that a solution to this uncertainty about genetically modified foods is to encourage people to not only act as consumers but act as participants in the ongoing process that is food biotechnology. Consumers who are scientifically aware and able to voice their thoughts are more likely to feel less uncertain about genetically modified crops. (Hunt) Has the introduction of genetically modified foods brought about legal controversy before the government? The answer is a resounding yes. A number of consumers have publically expressed concern over not knowing which food items they purchase contain genetic modifications. A statement from the American Association for the Advancement of Science released in 2012 indicated that a mandate on the labelling of genetically modified foods could mislead and falsely alarm consumers. (American Association for the Advancement of Science, This same statement notes that other prominent organizations, such as the American Medical Association, World Health Organization, and the

11 U.S. National Academy of Sciences, all conclude that the consumption of genetically modified foods poses no hazard to the health of humans. Three governmental entities oversee the regulation and issues surrounding genetically modified organisms; they are the Environmental Protection Agency, the United States Department of Agriculture, and the Food and Drug Administration. Often hidden from public limelight is the debate over patenting genes, as well as how these controversies interact with each of the aforementioned governmental entities. In 2013, the federal Supreme Court ruled that human genes cannot be patented, but crop seeds engineered in research laboratories can be patented. For example, farmers who attempt to develop a new seed from Monsanto s patented seeds may not do so without paying a fee to Monsanto. (Liptak) Future Directions and Conclusion Genetic modification of organisms holds significant promise for future endeavors; the technology is now available for genetic modification of essentially any organism. Z. mays is not the only major crop that is widely grown as a GMO; genetically modified soybeans, papayas, and cotton are all found in different regions across the world. Each contain a unique set of transgenes that best benefit each crop s specific needs. Although genetically modified crops are common, problems in the future will inevitably occur. Already, insect and pest resistance against the genetic product has been reported in research reports. Research endeavors in this field will be ongoing as the need to engineer new genes to which insects and pests will not be resistant persists for generations to come. Despite the incredibly strong scientific evidence that genetically modified Z. mays poses no threat to human health, ongoing studies will continue to further support the safety of genetically modified crops. More education and attempts to inform society about the safety of

12 genetically modified foods are needed to demonstrate to the general public that these food products are no cause for alarm. Unfortunately, many myths circulate about genetically modified foods, and if this fear is allowed to continually penetrate society, consumers will be falsely burdened with misinformation. As more people accept the reality of the benefits of genetically modifying crops, the less divisive this issue will become in society. The continued use of biotechnology has demonstrated its true promise for bettering our society through the safe modification of crops; the ongoing use of genetically modified crops is just one of many ways that modern recombinant DNA technology is being applied for benefit of mankind.

13 Works Cited American Association for the Advancement of Science. AAAS Board of Directors: Legally Mandating GM Food Labels Could Mislead and Falsely Alarm Consumers. 25 October April < Chelsea Snell, Aude Bernheim, Jean-Baptiste Berge, Marcel Kuntz, Gerard Pascal, Alain Paris, Agnes E Ricroch. "Assessment of the health impact of GM plant diets in long-term and multigenerational animal feeding trials: a literature review." Gerhard Flachowsky, Andrew Chesson, Karen Aulrich. "Animal nutrition with feeds from genetically modified plants." Archvies of Animal Nutrition February Griffiths, Anthony. "Recombinant DNA Technology." Encyclopedia Britannica 16 May Hunt, Lesley. "Factors determining the public understanding of GM technologies." AgBioTechNet Joel Spiroux de Vendomois, Francois Roullier, Dominique Cellier, Gilles-Eric Seralini. "A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health." International Journal of Biological Sciences (2009): Liptak, Adam. Supreme Court Supports Monsanto in Seed-Replication Case. The New York Times. 13 May < National Agricultural Statistics Service. Acreage. Washington, DC, 30 June 2010.

14 Organisation for Economic Co-operation and Development (OECD). BioTrack Product Database. n.d. 4 April < 8746%C3%98-4>. Paolo Castiglioni, Dave Warner, Robert J. Bensen, Don C. Anstrom, Jay Harrison, Martin Stoecker, Mark Abad, Ganesh Kumar. "Bacterial RNA Chaperones Confer Abiotic Stress Tolerance in Plants and Improved Grain Yield in Maize under Water-Limited Conditions." Plant Physiology 147 (2008): Peairs, F.B. "Colorado State University Extension." September Bt Corn: Health and the Environment. < R.H. Phipps, J.R. Park. "Environmental Benefits of Genetically Modified Crops: Global and European Perspectives on Their Ability to Reduce Pesticide Use." Journal of Animal and Feed Sciences (2002): University of California San Diego. History of Bt. n.d <