The Debate over Genetically Modified Foods
The Debate over Genetically Modified Foods [pic]
Addresses:
1. SC.912.L.16.10: Evaluate the impact of biotechnology on the individual, society and the environment, including medical and ethical issues.
2. SC.912.L.16.9: Explain how and why the genetic code is universal and is common to almost all organisms.
3. Rice with built-in Vitamin A that can help prevent blindness in 100 million children suffering from Vitamin A deficiency;
4. A tomato that softens more slowly, allowing it to develop longer on the vine and keep longer on the shelf;
5. Potatoes that absorb less fat when fried, changing the ever-popular french fries from junk food into a more nutritional food;
6. Strawberry crops that can survive frost;
7. An apple with a vaccine against a virus that causes childhood pneumonia.
These are some of the benefits promised by biotechnology. The debate over its benefits and safety, however, continues. Do we really need to fear mutant weeds, killer tomatoes, and giant corn and will the benefits be delivered?
Conventional Breeding versus Genetically Modified (GM) Crops
For thousands of years farmers have used a process of selection and cross breeding to continually improve the yield and quality of crops. However, traditional breeding methods are slow, requiring intensive labor: while trying to get a desirable trait in a bred species, undesirable traits will appear and breeders must continue the process over many generations until all the undesirable traits are bred out.
In contrast, GM organisms are given one specific gene or a few genes together; therefore, the organism acquires the desired trait within a single generation. However, this technology can be unpredictable and some scientists believe it can produce potentially dangerous results unless better testing methods are developed. Nonetheless, GM plants are now grown on about 130 million acres in 13 countries, including Argentina, Canada, and Germany. In 2001, 3.6 million acres were used for GM crops in the U.S. More than 60% of all processed foods in the U.S. contain ingredients from GM soybeans, corn, or canola.1
Unlike with traditional breeding approaches where the species must be the same or very closely related, GM crops can receive genes from distant species, even bacteria and viruses. A typical example of a GM crop in the market in Australia is cotton known as Ingard™.6 Scientists inserted a naturally occurring gene from a soil bacterium known as Bacillus thuringiensis into the cotton which renders the cotton resistant to the heliothis caterpillar, a major threat to the cotton industry. In this example, an appropriate and selected gene was inserted into the cotton from a bacteria rather than being inherited from a similar species as in traditional breeding approaches.10
Benefits: one side of the debate
Economical
GM supporters tell farmers that they stand to reap enormous profits from growing GM crops. Initially, the cost is high but money is saved over time in lower production costs, fewer pest problems, reduced use of pesticides, and better yields. To produce GM crops, modern biotechnology is used which requires highly skilled people and sophisticated and expensive equipment which increases the cost of the seed.7
Herbicide/Pesticide-resistant crops
So what other advantages do GM crops hold for farmers? GM crops can be produced to be herbicide resistant. This means that farmers could spray these crops with herbicide and kill the weeds, without affecting the crop. In effect, the amount of herbicide used in one season would be reduced, with a subsequent reduction in costs for farmers and consumers. For Ingard™ cotton, pest resistance was built into the cotton, hence reducing and even removing the need for pesticides, which are not only expensive but, more importantly, harmful to the environment.
Environmentally Hardy
Biotechnology companies are even experimenting with crops that can be genetically modified to be drought and salt-tolerant or less reliant on fertilizer, opening up new areas to be farmed and leading to increased productivity.
Better quality animal products
Even animals can be genetically modified to be leaner, grow faster, and need less food. They could be modified to have special characteristics, such as greater milk production in cows. These modifications again lead to improved productivity for farmers and ultimately lower costs for the consumer. Modified crops could perhaps prevent outbreaks such as foot and mouth disease, which has devastated many farmers and local economies. No such products have been released to date; however, some are under consideration for release. For example, GM salmon, capable of growing almost 30 times faster than natural salmon, may soon be approved by the FDA (Food and Drug Administration) in the U.S. for release into open waters without a single study on the impact on human health or the environment.5
The following are some examples of food plants that are undergoing field trials:10
8. apples that resist insect attack
9. bananas free of viruses and worm parasites
10. coffee with a lower caffeine content
11. cabbage that resists caterpillar attacks
12. melons that have a longer shelf life
13. sunflowers that produce oil with lower saturated fat
Risks: the other side of the debate
Environmental damage
One problem with GM crops is that there is little known about what effect they will have in, say, 20 years time. The genetic structure of any living organism is complex and GM crop tests focus on short-term effects. Not all the effects of introducing a foreign gene into the intricate genetic structure of an organism can be tested.
Then there is always the possibility that we may not be able to destroy GM crops once they spread into the environment. In Europe, for example, a strain of sugar beet that was genetically modified to be resistant to a particular herbicide has inadvertently acquired the genes to resist another.7 This was discovered when farmers attempted to destroy the crop in Britain, France and the Netherlands, where it was being tested, and 0.5% of the crop survived.7 More noxious herbicides had to be used to remove the remainder of the weeds. What if this herbicide resistance passed on to weeds?
Risk to food web
A further complication is that the pesticide produced in the crop may unintentionally harm creatures. In Britain, a native farm bird, the Skylark, was indirectly affected by the introduction of GM sugar beets designed to resist herbicides. In planting this crop, the weeds were reduced substantially. However, since the birds rely on the seeds of this weed in autumn and winter, researchers expect that up to 80% of the Skylark population would have to find other means of finding food.4
GM crops may also pose a health risk to native animals that eat them. The animals may be poisoned by the built-in pesticides. Tests in the U.S. showed that 44% of caterpillars of the monarch butterfly died when fed large amounts of pollen from GM corn.8 Relatedly, what happens when pests develop resistance to the pesticides used?
Cross-pollination
Cross-pollination is a concern for both GM crops and conventional breeding, especially with the more serious weeds that are closely related to the crops. With careful management this may be avoided. For example, there is a type of maize that will not breed with other strains and scientists are hoping that it could help to prevent cross-pollination.3 Genetic modification to herbicide resistant crops could insert the gene that prevents the problem. The number of herbicide-tolerant weeds has increased over the years from a single report in 1978 to the 188 herbicide-tolerant weed types in 42 countries reported in 1997.6 They are an ever-increasing problem. Will genes from GM plants spread to other plants, creating superweeds and superbugs we won’t be able to control?
GM mix-ups
Humans can inadvertently eat foods that contain GM products meant as animal feed, i.e., crops modified for increased productivity in animals. This happened in the U.S., where traces of a StarLink GM crop, restricted for use only in feed, were found in taco shells.2 Apparently no one became ill but other such occurrences may lead to health problems.
Allergies and toxins
Very little scientific information exists about the risk of GM food on human health. One major report by Dr. Arpad Pusztai, published on this web site, explains how GM foods could trigger new allergies and contain toxins that may be harmful.9 However, a document published by the World Health Organization11 shows no adverse events to date.
Disease
Another concern is disease. Since some crops are modified using the DNA from viruses and bacteria, will we see new diseases emerge? What about the GM crops that have antibiotic-resistant marker genes? Marker genes are used by scientists to determine whether their genetic modification of an organism was successful. Will these antibiotic-resistant genes be transferred to microorganisms that cause disease? We already have a problem with ineffective antibiotics. How then will we develop new drugs to fight these new superbugs?
Conclusion
Proponents of GM crops claim that advantages may be many, such as:
14. improved storage and nutritional quality
15. pest and disease resistance
16. selective herbicide tolerance
17. tolerance of water, temperature and saline extremes
18. improved animal welfare
19. higher yields and quality to feed an ever increasing global population
While it is not possible to make general statements on the safety of all GM foods, to date, no adverse health effects caused by products approved for sale have been documented.11 Although there is now broad scientific consensus that GE crops on the market are safe to eat12, some scientists and advocacy groups such as Greenpeace and World Wildlife Fund call for additional and more rigorous testing before marketing genetically engineered food. Living organisms are complex and tampering with their genes may have unintended effects.
(This article was heavily edited and altered for clarity and utility with the CIS Model by Troy Suarez. Please refer to the original article for reference . This article has a 1400L).
Kerryn Sakko is an undergraduate student at Adelaide University, Australia, studying for a double degree in chemical engineering, mathematics and computer science. In 2001, she represented Australia, with 19 other students from around the country, at the APEC Youth Science Forum held in Singapore. © 2002, American Institute of Biological Sciences.
References
20. Ackerman, Jennifer. 2002. “Food: How Safe? How Altered?” National Geographic, May issue.
21. Boyce, Nell. 2000. “Taco Trouble.” New Scientist: Vol. 169, No. 2259, 7 October.
22. Boyce, Nell. 2000. “A Breed Apart.” New Scientist: Vol. 168, No. 2261, 21 October.
23. Firbank, Les E. and Frank Forcella. 2000. “Genetically Modified Crops and Farmland Biodiversity. Science: Vol. 289, No. 5484, 1 Sept.
24. Friends of the Earth. 2002. “Petition to President Bush: Don’t Turn Your Back!”
25. Gene Technology Information Service provided by Biotechnology Australia in partnership with the University of Melbourne
26. Gene Technology in Australia website. . Accessed 6/02.
27. Biotechnology Australia website. . Accessed 6/02.
28. Pusztai, Arpad. June 2001. “GM foods: Are they a risk to animal/human health?” . Accessed 6/02.
29. National Centre for Biotechnology Education website. . Accessed 6/02.
30. 20 questions on genetically modified foods. World Health Organization. Accessed 8/12.
31. NRC. (2004). Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. National Academies Press.
32. Le Curieux-Belfond O., Vandelac L., Caron J., Seralini G.E. (2009). "Factors to consider before production and commercialization of aquatic genetically modified organisms: the case of transgenic salmon". Env. Sci. Policy 12 (2): 170–189
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CIS Unit
The Debate over Genetically Modified Foods
(9th and 10th grade Biology)
33. SC.912.L.16.10: Evaluate the impact of biotechnology on the individual, society and the environment, including medical and ethical issues.
34. SC.912.L.16.9 Explain how and why the genetic code is universal and is common to almost all organisms.
CIS Lesson
The Debate over Genetically Modified Foods
35. Hook Engage:
36. Question #1
Predict the risks and benefits of using genetically modified organisms.
37. Pass out article
38. Define vocabulary
39.
40. Deficiency
41. Biotechnology
42. Conventional
43. Acquires
44. Renders
45. Sophisticated
46. Herbicide
47. Pesticide
48. Saturated
49. Intricate
50. Inadvertently
51. Noxious
52. Cross-pollination
53. Maize
54. Proponents
55. Text-marking
R = Risk of Genetically Modified Organisms
B = Benefits of Genetically Modified Organisms
56. Question #2
What are the risks and benefits of using genetically modified organisms?
57. Note-taking: What are the greatest challenges to those wishing to ban GMOs?
58. Vote
According to what you read in the text(s), which is the greatest challenge to those wishing to ban GMOs?
| |Individual |Group |Recount Individual |
|Monetary benefits | | | |
|Health benefits | | | |
|Inconclusive research with lots of | | | |
|unknowns | | | |
|Food demand/shortages around the world| | | |
59. An individual representing each position presents a persuasive argument in favor of their position. A recount is conducted to allow student to change their vote.
60. Question #3
You are a politician running for office and you must take a stand either for or against the use of GMOs. Construct a letter detailing your position to your constituency. Lay out your position with a thesis statement that is supported with evidence from the provided text. Feel free to bring in additional research from other sources (be sure to cite those sources; 4 to 5 paragraphs).
The Debate over Genetically Modified Foods
Vocabulary
61. Deficiency: A lack or shortage
62. Biotechnology: The exploitation of biological processes for industrial and other purposes
63. Conventional: what is generally done or believed.
64. Acquires: to get or obtain
65. Renders: to make
66. Sophisticated: high degree of complexity
67. Herbicide: chemical that kills weeds
68. Pesticide: chemical that kills pests
69. Saturated: can hold no more
70. Intricate: very complicated and detailed
71. Inadvertently: without knowing or intention
72. Noxious: harmful or poisonous
73. Cross-pollination: transfer of pollen from one flower to another
74. Maize: corn
75. Proponents: supporters
Directed Note-Taking
Directions: Record notes containing the most important information relevant to the guiding question.
|Page/ |Notes |Monetary |Health |In-conclusive |Food demand / |
|Paragraph# | |benefits |benefits |research |shortages |
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Collaborative Work:
After completing your chart, be prepared to compare your notes with others.
Question Generator
Directions: Go back through the text and find words, phrases or statements that create questions in your mind. Discuss these questions in your group, and then document your group’s questions below.
|Page/ |Notes |Monetary |Health benefits |In-conclusive |Food demand / |
|Paragraph# | |benefits | |research |shortages |
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Collaborative Work:
After completing your chart, be prepared to compare your notes with others.
Directions: Write your answer to the question using information you learned in this unit. Be sure to use information from the text to justify your answer. Be sure to use complete sentences and correct punctuation and grammar.
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