Genetically Modified Foods

Applying scientific knowledge to engineer a better crop is not a new idea. We began doing so on a large scale around World War II. Crops were systematically bred and selected to improve yields. Chemical fertilizers, pesticides, and herbicides further increased agricultural productivity. This was the Green Revolution (Byravan).

Traditional breeding, as used in the Green Revolution, is a slow and tedious process. To transfer a trait, the breeder must first find a closely related species with the trait. In addition to taking time, finding the desired trait in a related species greatly limits the library of traits. With the trait located, the breeder then crosses and re-crosses the two species, selecting the best progeny to be the parents of the next generation (“More than one way to alter a plant,” “Traditional Plant Breeding”).

Recent scientific advances allowed scientists to directly transfer a segment of DNA between any two organisms (and the protein for which the DNA codes, and hence a trait). Just as with breeding, the first step of genetic modification is finding the desired trait in nature. The trait, however, can be from any organism’s genome because the genetic code is universal. Once the transgene is isolated, it is spliced to a promoter (a regulatory DNA segment) so that it will be expressed in plant cells. The gene and promoter are duplicated in bacteria then inserted into a cell culture. The cells are grown up into plants, and the ones showing the trait without any abnormalities are selected (“More than one way to alter a plant,” “Genetic engineering”). Using this technology to create a better crop is sometimes called the Second Green Revolution (Byravan).

There are two widespread genetic modifications: herbicide tolerance and insect resistance. Insect resistant crops carry a gene from the bacteria bacillus thuringiensis which produces the Bt toxin, a protein with insecticidal properties. This modification is commonly called Bt, after the bacteria. Herbicide tolerant crops are resistant to glyphosate, more commonly known as Roundup. They are often referred to by Monsanto’s brand name: Roundup Ready. (Monsanto is the leading manufacture of genetically modified crops as well as Roundup.) These two genetic enhancements are common in all the major crops: corn, soybeans, canola, and cotton (Mellon, “Genetically Modified Crops Marketed in the United States ”).

 

Nobody opposes food grown on traditionally bred crops and genetic engineering seems like a natural extension of breeding. Why then does it matter whether the gene was transferred through pollen or inserted by scientists? It is not the method of transfer that is worrisome; it is the genes that are transferred.

The Center for Food Safety demonstrates that, at the most basic level, people are afraid of the strange combinations of DNA scientists brew up. The central argument is as follows: scientists have created “potatoes with bacteria genes, ‘super pigs’ with human growth genes, fish with cattle growth genes. . . . At an alarming rate, these creations are now being patented and released into the environment. Currently, up to 40 percent of U.S. corn is genetically engineered as is 80 percent of soybeans.” Note that the rare Frankenstein alterations are followed by the two most commonly modified crops. Although the juxtaposition is misleading, it is an effective method of scaring people into opposing genetic modification. To add to the reader’s natural suspicion of eating tomatoes containing flounder genes, the article includes a list of the dangers: “Human health effects can include higher risks of toxcitiy, allergenicity, antibiotic resistance, immune-suppression, and cancer.” The article is also full of negative imagery: it describes genetically modified foods as “looming” and as having “invaded our grocery stores and our kitchen pantries.” The article is surprisingly forceful, for one that does not present a single solid piece of evidence.

Since we want to reach a rational conclusion, examining rhetoric will not help. Only carefully studying, evaluating, and weighing the risks and benefits will lead to a valid conclusion. The risks include toxicity and allergic reactions, the emergence of resistant pests, and the spread of the transgenes. We will gauge the dangers by looking at the arguments of activists and scientists then examine the benefits.

The concern over allergic reaction has a biological basis. Researchers have found similar regions proteins coded for by inserted genes and known allergens: “Two-thirds of the thirty-three aligned transgenic proteins displayed identical stretches of at least six contiguous amino acids with allergenic proteins” (Kleter et al, “Results”). Because small but specific amino acid sequences cause allergies, a six amino acid match relevant (Kleter et al, “Background”). One should remember that Kleter’s research shows that allergic reactions are possible, not that they are certain.

The Soil Association, an activist group, lists allergies as one of the many dangers of genetically modified food. The Association gives some evidence: they cite a study done by Padgette that finds a certain type of genetically modified soy has 27% more of “an allergen trypsin inhibitor” (2). No explanation of the study is given so the reader cannot interpret the results. The reader probably assumes that 27% more people are allergic to this unnamed type of soy, which is likely incorrect. The other piece of evidence is that fifty people had allergic reactions when food was contaminated with StarLink corn in 2000 (2). We do not know the severity of the reactions or the number of people who ate contaminated food. Therefore, no conclusions can be drawn from this data.

Regardless of how Soil Association spins the evidence, there have been no major incidents involving allergies and genetically modified foods. According to Sujatha Byravan, a biologist working for The Council for Responsible Genetics, we have not seen an increase in allergies as genetically modified food becomes more prevalent. Byravan also argued that, based on our lack of evidence for allergies, we cannot conclude that genetically modified food is safe.

Safety would not be an issue if we had a better testing method. Our current method is that of substantial equivalence. According to a research paper on the topic, substantial equivalency relies on finding and studying every difference between the genetically modified plant and the original. Identifying every single difference is nearly impossible; there is always a chance that the key difference will be overlooked (Konig et al, 1078). Activists are eager to add that substantial equivalency ignores the interactions between protein differences since they are studied separately (Byravan).

It turns out that substantial equivalence is the best testing method we have. Traditionally, the potential toxin is tested by theoretical analysis, in vitro analysis, and animal studies (Konig et al, 1054). In vitro analysis tests for toxicity in a cell culture. The technique is fast and cheap but “extrapolation from in vitro tests to in vivo situations is often challenging” (Konig et al, 1054), meaning the results do not necessarily scale to a whole organism. In animal studies, animals are given a dosage large enough to cause noticeable harm. The adverse effects are then extrapolated down to a more normal dosage. This method fails because animals can only eat so much; they cannot be fed “large multiples” of the expected human exposure. No adverse effects are observed at lower doses in animals but this does not mean there are none (Konig et al, 1055). It appears that we lack an accurate and complete method of testing the safety of foods. Substantial equivalence is incomplete; traditional tests are not sensitive enough.

Some are worried by the lack of regulation of genetically modified crops. They need only pass three regulatory bodies: the FDA, EPA, and USDA. The FDA (Food and Drug Administration) certifies the safety of the crop based on data provided by the company. No independent testing is required. The EPA (Environmental Protection Agency) only has jurisdiction over crops that produce pesticides, such as Bt corn. The USDA (United States Department of Agriculture) is concerned with the crop not being a “pest plant” (Mellon, “ U.S. approach to the regulation of biotechnology products”).

The other major concern with genetically modified crops is environmental harm, primarily horizontal transfer: the transfer of the inserted gene to other organisms. Horizontal transfer can occur when a genetically modified plant pollinates a closely related wild plant. The wild plant with the transgene gains an advantage over those without it, causing natural selection to increase the proportion of plants with the transgene. According to the Union of Concerned Scientists, studies have shown that the Bt gene readily moves from Bt sunflower crops to wild sunflowers and gives them a selective edge. The same happens for virus resistant squash plants (Mellon, “Research on environmental risks”). People often worry that the transfer of herbicide tolerance genes will create herbicide resistant “super weeds.”

It turns out that the increase in herbicide resistant weeds due to simple selective pressures rather than gene transfer. In the past few years, there has been an increase in Roundup resistant weeds. There use to be only one known glyposate resistant weed, and it was in Australia. Now there are several. To solve the problem, farmers are mixing more potent herbicides with Roundup (Mellon, “Resistant pests”).

No new Bt resistant pests have been found so far. Perhaps this is due to mandatory insect resistance management. Farmers are required to plant refuges of non-Bt crops near Bt crops to lessen the selective pressure on insects to become Bt resistant. The refuges will only delay the emergence of Bt resistant pests (Mellon, “Resistant pests”).

Most of the few groups that favor genetic modification are either funded or copyrighted by Monsanto, the major seed manufacturer. Their one-sided view of the issue is naturally a direct result of Monsanto’s stake in the public image of genetically modified food. An example of such a group is The Council for Biotechnology Information. In their “about us” section, they clearly state their motive: “Our research tells us that the more people learn about biotechnology, the more they will welcome it into the marketplace.” It is true that knowledge about genetic engineering eliminates the natural skepticism of something one doesn’t understand. The Council for Biotechnology Information, however, is referring to a different kind of information: “biotech products…offer more nutritious and better tasting food, we all stand to benefit directly.” They mean to promote every advantage of genetic modification, even those that are questionable. Genetic engineering is not about taste and nutrition; it is about productivity and profit.

Gene Transfer

The majority of the arguments made by the group are unconvincing. On the topic of horizontal transfer, the group tries to sidestep the problems. Instead of acknowledging the problem, they state that “the release of genetically enhanced genes is as likely to occur as with conventional varieties” (“Biotechnology and Genetic Diversity”). Since not many people are fooled, the Council tries to argue that horizontal transfer does not cause harm. They handle the defense on a case-by-case basis and only chose the cases that support their argument. For corn, they claim that there is no closely related wild corn into which the enhanced genes can move (“Biotechnology and Genetic Diversity”). There is, however, wild corn in Mexico (Byravan). For mold resistance in sunflowers, they argue that the transfer “will have little effect on the evolutionary dynamics of wild sunflower populations” because wild sunflowers are already mold resistant. For Roundup Ready crops, they assert that gene transfer to wild plants outside the fields will have no effect: “A gene for herbicide tolerance…isn’t likely to confer an advantage to a plant in the wild because herbicides won’t be encountered there” (“Biotechnology and Genetic Diversity”).

Conservative Tillage

The most believable benefit to using Roundup Ready crops is the elimination of the need to plow. Plowing is a form of weed control. If weed can be controlled chemically, the farmer does not need to plow. This agricultural practice is known a conservative tillage. Conservative tillage improves soil quality and reduces erosion. Side benefits include creating a habitat for wild animals and saving fuel (“Conservative Tillage”). These benefits will only last as long as there are very few herbicide resistant weeds (Byravan).

Roundup Safety

The use of large quantities of Roundup to control weeds raises the issue of the safety of Roundup. Monsanto, the manufacture of Roundup, naturally claims it is completely nontoxic. They support their claim with a list of quotations from the EPA, WHO, and two research papers. Some examples are as follows: “It has been concluded that there is minimal risk to small mammals from the application of glyphosate products” (“Authoritative sources for glyphosate information,” “Ecological Risk Assessment”), “…the Roundup formulation is considered to be practically nontoxic” (“Authoritative sources,” “Safety Evaluation and Risk Assessment”), “Exposure to workers and other applicators generally is not expected to pose undue risks” (“Authoritative sources,” “EPA”).

There is an article in The Journal of Pesticide Reform that directly conflicts with Monsanto’s “Authoritative sources.” Aside from finding that glyphosate itself has adverse effects, the paper also reveals that the so-called inert ingredients in Roundup are toxic. The inert ingredients are added to the herbicide to aid application and do not need to be listed (Cox, 3-6).

Monsanto had a response posted on its website. It called the journal a magazine and accused the author of citing “published studies to give the impression of veracity and impartiality.” She was also accused of misleading the reader by not explaining that “acutely toxic” does not mean “very toxic” (“Glyphosate and Journal of Pesticide Reform Articles”).

Cox’s article dealt with very high doses of Roundup but Monsanto did not emphasize this in its defense. The closest the company comes is as follows: Cox implies “that effects seen at very high doses could also occur at any lower dose. Ms. Cox generally ignores the essential dose-response information” (“Glyphosate and Journal”). It appears that Roundup is relatively nontoxic at low doses. Naturally, the ill effects increase with dosage.

 

Conclusion

 

If we step back from the details and look at the motivations, the situation makes sense. Monsanto has a strong motivation to promote genetically modified food but does not focus on average people since they do not make policies or decide which crops to grow. Since the average person does not benefit from genetically modified food, he has no reason to support it. He has no motivation to take his time to advocate genetically modified food. Other people want to do what they believe is right so they oppose genetic modification. This explains the abundance of opposition and the lack of independent support.

When I asked Sujantha Byravan about the theory, she said it was her primary reason for opposing genetic modifications. She asked, “Why should I support genetically modified food?” and went on to explain how technology should benefit the people at least a little bit. Genetically modified food only benefits Monsanto and large farmers. It will not end world hunger as it supposedly will because there is already enough food. In fact there is too much. The problems are war and poverty (Byravan).

Many people become too involved thinking about horizontal transfer and allergens and fail to see how simple the conclusion is. If we weigh the risks and benefits, we find that the logical choice is to oppose genetically modified foods. Often opposing a new technology is called anti-science. It does not hinder science because genetically modified foods do not advance our knowledge or understanding of science.

Bibliography

 

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