Genetically modified food

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Genetically modified (GM) foods are foods derived from genetically modified organisms. The DNA of genetically modified organisms has been modified through genetic engineering, unlike similar food organisms developed through the conventional genetic modification of selective breeding (plant breeding and animal breeding) or mutation breeding. GM foods were first put on the market in the early 1990s. Typically, genetically modified foods are transgenic plant products: soybean, corn, canola, and cotton seed oil, but animal products have been developed. For example, in 2006 a pig engineered to produce omega-3 fatty acids through the expression of a roundworm gene was controversially[1][2] produced.[3] Researchers have also developed a genetically-modified breed of pigs that are able to absorb plant phosphorus more efficiently, and as a consequence the phosphorus content of their manure is reduced by as much as 60%. [4]

Critics have objected to GM foods on several grounds, including perceived safety issues,[5] ecological concerns, and economic concerns raised by the fact that these organisms are subject to intellectual property law.

Contents

[edit] Method

Main articles: Genetic engineering and Genetic transformation

Genetic engineering begins with the identification and isolation of a gene which expresses a desirable trait, with the aid of restriction enzymes. Then a recipient plant or animal is selected, and the gene is inserted and incorporated into its genome through a vector such as agrobacterium, through a gene gun shooting an elemental particle covered in plasmid DNA, electroporation, or a virus. Once part of the recipient, the newly inserted gene becomes part of the genome of the recipient and is regulated in the same way as its other genes.

The advantage of genetic engineering, as illustrated in the next section, is that genes can be introduced that do not occur in the germplasm of the target species and its closely related wild relatives.

[edit] Development

The first commercially grown genetically modified whole food crop was a tomato (called FlavrSavr), which was modified to ripen more slowly by Californian company Calgene.[6] Calgene took the initiative to obtain FDA approval for its release in 1994 without any special labeling, although legally no such approval was required.[7] It was welcomed by consumers who purchased the fruit at a substantial premium over the price of regular tomatoes. However, production problems[6] and competition from a conventionally bred, longer shelf-life variety prevented the product from becoming profitable. A variant of the Flavr Savr was used by Zeneca to produce tomato paste which was sold in Europe during the summer of 1996.[8] The labeling and pricing were designed as a marketing experiment, which proved, at the time, that European consumers would accept genetically engineered foods.

Currently, there are a number of food species in which a genetically modified version exists.

Food Properties of the genetically modified variety Modification Percent in UK Percent in world
Soybeans Resistant to glyphosate or glufosinate herbicides Herbicide resistant gene taken from bacteria inserted into soybean 89% TBA
Corn, field Resistant to glyphosate or glufosinate herbicides, Insect resistance - using Bt proteins some previously used as pesticides in organic crop production.

Vitamin-enriched corn derived from South African white corn variety M37W has bright orange kernels, with 169x increase in beta carotene, 6x the vitamin C and 2x folate.[9]

 New genes added/transferred into plant genome. 60% TBA
Cotton (cottonseed oil) Pest-resistant cotton B.t. crystal protein gene added/transferred into plant genome 83% TBA
Hawaiian Papaya Variety is resistant to the Papaya ringspot virus.[10] New gene added/transferred into plant genome +50% TBA
Tomatoes Variety in which the production of the enzyme polygalacturonase (PG) is suppressed, retarding fruit softening after harvesting.[11] A reverse copy (an antisense gene) of the gene responsible for the production of PG enzyme added into plant genome Taken off the market due to commercial failure. None
Potatoes Amflora variety produces starch composed almost exclusively of the amylopectin component of starch.[12] The gene for granule bound starch synthase (GBSS) (the key enzyme for the synthesis of amylose) was switched off by inserting antisense copy of the GBSS gene. Amflora will be produced solely under contract farming conditions and not made available on the general market. TBA
Rapeseed (Canola) Resistance to herbicides (glyphosate or glufosinate), High laurate canola[13] New genes added/transferred into plant genome 75% TBA
Sugar cane Resistance to certain pesticides, High-sucrose cane. New genes added/transferred into plant genome TBA TBA
Sugar beet Resistance to glyphosate, glufosinate herbicides New genes added/transferred into plant genome TBA TBA
Sweet corn Produces its own bioinsecticide (B.t. toxin) Gene from the bacteria Bacillus thuringiensis added to the plant. TBA TBA
Rice Genetically modified to contain high amounts of Vitamin A (beta-carotene) "Golden rice" Three new genes implanted: two from daffodils and the third from a bacterium TBA TBA

In addition, various genetically engineered micro-organisms are routinely used as sources of enzymes for the manufacture of a wide variety of processed foods. These include alpha-amylase from bacteria, which converts starch to simple sugars, chymosin from bacteria or fungi that clots milk protein for cheese making, and pectinesterase from fungi which improves fruit juice clarity.[14]

[edit] Growing GM crops

Between 1997 and 2005, the total surface area of land cultivated with GMOs had increased by a factor of 50, from 17,000 km2 (4.2 million acres) to 900,000 km2 (222 million acres).

Although most GM crops are grown in North America, in recent years there has been rapid growth in the area sown in developing countries. For instance in 2005 the largest increase in crop area planted to GM crops (soybeans) was in Brazil (94,000 km2 in 2005 versus 50,000 km2 in 2004.)[15] There has also been rapid and continuing expansion of GM cotton varieties in India since 2002. (Cotton is a major source of vegetable cooking oil and animal feed.) It is predicted that in 2008/9 32,000 km2 of GM cotton will be harvested in India (up more than 100 percent from the previous season). Indian national average cotton yields of GM cotton were seven times lower in 2002, because the parental cotton plant used in the genetic engineered variant was not well suited to the climate of India and failed. The publicity given to transgenic trait Bt insect resistance has encouraged the adoption of better performing hybrid cotton varieties, and the Bt trait has substantially reduced losses to insect predation. Though controversial and often disputed, economic and environmental benefits of GM cotton in India to the individual farmer have been documented.[16][17]

In 2003, countries that grew 99% of the global transgenic crops were the United States (63%), Argentina (21%), Canada (6%), Brazil (4%), China (4%), and South Africa (1%).[18] The Grocery Manufacturers of America estimate that 75% of all processed foods in the U.S. contain a GM ingredient[19] . In particular, Bt corn, which produces the pesticide within the plant itself, is widely grown, as are soybeans genetically designed to tolerate glyphosate herbicides. These constitute "input-traits" are aimed to financially benefit the producers, have indirect environmental benefits and marginal cost benefits to consumers.

In the US, by 2006 89% of the planted area of soybeans, 83% of cotton, and 61% maize were genetically modified varieties. Genetically modified soybeans carried herbicide-tolerant traits only, but maize and cotton carried both herbicide tolerance and insect protection traits (the latter largely the Bacillus thuringiensis Bt insecticidal protein). In the period 2002 to 2006, there were significant increases in the area planted to Bt protected cotton and maize, and herbicide tolerant maize also increased in sown area.[20]

[edit] Crop yields

Several studies supported by organic growers have claimed that genetically modified varieties of plants do not produce higher crop yields than normal plants.[21]

One study by Charles Benbrook, Chief Scientist of the Organic Center, found that genetically engineered Roundup Ready soybeans do not increase yields (Bendrook, 1999). The report reviewed over 8,200 university trials in 1998 and found that Roundup Ready soybeans yielded 7-10% less than similar natural varieties. In addition, the same study found that farmers used 5-10 times more herbicide (Roundup) on Roundup Ready soybeans than on conventional ones.[22]

[edit] Coexistence and traceability

The United States and Canada do not require labeling of genetically modifed foods.[23] However in certain other regions, such as the European Union, Japan, Malaysia and Australia, governments have required labeling so consumers can exercise choice between foods that have genetically modified, conventional or organic origins.[24][25] This requires a labeling system as well as the reliable separation of GM and non-GM organisms at production level and throughout the whole processing chain.[24][25] Research suggests that this may prove impossible.[citation needed]

For traceability, the OECD has introduced a "unique identifier" which is given to any GMO when it is approved. This unique identifier must be forwarded at every stage of processing.[citation needed] Many countries have established labeling regulations and guidelines on coexistence and traceability. Research projects such as Co-Extra, SIGMEA and Transcontainer are aimed at investigating improved methods for ensuring coexistence and providing stakeholders the tools required for the implementation of coexistence and traceability.[citation needed]

[edit] Detection

Testing on GMOs in food and feed is routinely done using molecular techniques like DNA microarrays or qPCR. These tests can be based on screening genetic elements (like p35S, tNos, pat, or bar) or event-specific markers for the official GMOs (like Mon810, Bt11, or GT73). The array-based method combines multiplex PCR and array technology to screen samples for different potential GMOs [26], combining different approaches (screening elements, plant-specific markers, and event-specific markers).

The qPCR is used to detect specific GMO events by usage of specific primers for screening elements or event-specific markers. Controls are necessary to avoid false positive or false negative results. For example, a test for CaMV is used to avoid a false positive in the event of a virus-contaminated sample.

[edit] Controversy

Main article: GM food controversy

Some scientists[27] argue that there is more than enough food in the world and that the hunger crisis is caused by problems in food distribution and politics, not production, so people should not be offered food that may carry any degree of risk.[28][29] This argument assumes that genetically modified foods present risks not present in traditional foodstuffs, which are demonstrably not free of risk. Recently some critics have changed their minds on the issue with respect to the need for additional food supplies.[30]

In 1998 Rowett Research Institute scientist Árpád Pusztai reported that consumption of potatoes genetically modified to contain lectin had adverse intestinal effects on rats.[31] Pusztai eventually published a paper, co-authored by Stanley Ewen, in the journal, The Lancet. The paper claimed to show that rats fed on potatoes genetically modified with the snowdrop lectin had unusual changes to their gut tissue when compared with rats fed on non modified potatoes.[31][32] However, the experiment has been criticised on the grounds that the unmodified potatoes were not a fair control diet.[33]

[edit] Economic and political effects

Adoption of genetically-engineered crops in the United States.[34]
  • Many proponents of genetic engineered crops claim they lower pesticide usage and have brought higher yields and profitability to many farmers, including those in developing nations.[35] This view is supported by the widespread adoption of genetically-engineered crops by farmers in regions where they are available (see figure). A few genetic engineering licenses allow farmers in less economically developed countries to save seeds for next year's planting.[citation needed]
  • In August 2003, Zambia cut off the flow of Genetically Modified Food (mostly maize) from UN's World Food Programme. This left a famine-stricken population without food aid.
  • In December 2005 the Zambian government changed its mind in the face of further famine and allowed the importation of GM maize.[36] However, the Zambian Minister for Agriculture Mundia Sikatana has insisted that the ban on genetically modified maize remains, saying "We do not want GM (genetically modified) foods and our hope is that all of us can continue to produce non-GM foods."[37][38]
  • In April 2004 Hugo Chávez announced a total ban on genetically modified seeds in Venezuela.[39]
  • In January 2005, the Hungarian government announced a ban on importing and planting of genetic modified maize seeds, which was subsequently authorized by the EU.[40]
  • On August 18, 2006, American exports of rice to Europe were interrupted when much of the U.S. crop was confirmed to be contaminated with unapproved engineered genes, possibly due to accidental cross-pollination with conventional crops.[41]

[edit] Intellectual property

Traditionally, farmers in all nations saved their own seed from year to year. Allowing farmers to follow this practice with genetically modified seed would result in seed developers losing the ability to profit from their breeding work. Therefore, genetically-modified seed are subject to licensing by their developers in contracts that are written to prevent farmers from following this traditional practice.[42] Many objections to genetically modified food crops are based on this change.

Main article: Monsanto Canada Inc. v. Schmeiser

Enforcement of patents on genetically modified plants is often contentious, especially because of gene flow. In 1998, 95-98 percent of about 10 km2 planted with canola by Canadian farmer Percy Schmeiser were found to contain Monsanto's patented Roundup Ready gene although Schmeiser had never purchased seed from Monsanto.[43] The initial source of the plants was undetermined, and could have been through either gene flow or intentional theft. However, the overwhelming predominance of the trait implied that Schmeiser must have intentionally selected for it. The court determined that Schmeiser had saved seed from areas on and adjacent to his property where Roundup had been sprayed, such as ditches and near power poles.[44]

Although unable to prove direct theft, Monsanto sued Schmeiser for piracy since he knowingly grew Roundup Ready plants without paying royalties(Ibid). The case made it to the Canadian Supreme Court, which in 2004 ruled 5 to 4 in Monsanto’s favor.[43][44] The dissenting judges focused primarily on the fact that Monsanto's patents covered only the gene itself and glyphosate resistant cells, and failed to cover transgenic plants in their entirety. All of the judges agreed that Schmeiser would not have to pay any damages since he had not benefited from his use of the genetically modified seed.

In response to criticism, Monsanto Canada's Director of Public Affairs stated that "It is not, nor has it ever been Monsanto Canada's policy to enforce its patent on Roundup Ready crops when they are present on a farmer's field by accident...Only when there has been a knowing and deliberate violation of its patent rights will Monsanto act."[45]

[edit] Future developments

Future envisaged applications of GMOs are diverse and include drugs in food, bananas that produce human vaccines against infectious diseases such as Hepatitis B,[46] 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 plastics with unique properties.[47] While their practicality or efficacy in commercial production has yet to be fully tested, the next decade may see exponential increases in GM product development as researchers gain increasing access to genomic resources that are applicable to organisms beyond the scope of individual projects. Safety testing of these products will also, at the same time, be necessary to ensure that the perceived benefits will indeed outweigh the perceived and hidden costs of development. Plant scientists, backed by results of modern comprehensive profiling of crop composition, point out that crops modified using GM techniques are less likely to have unintended changes than are conventionally bred crops.[48][49]

[edit] Health Risks

In the United States, the FDA Center for Food Safety and Applied Nutrition must approve the nutritional characteristics of GMO foods on the basis of comparability to conventionally-produced foods. The table below shows the foods that had received FDA approval as of 2002.[50]

[edit] Gene transfer

As of January 2009 there has only been one human feeding study conducted on genetically modified foods. The study involved seven human volunteers who had their large intestines removed. These volunteers were to eat GM soy to see if the DNA of the GM soy transferred to the human gut bacteria. Researchers identified that three of the seven volunteers had transgenes from GM soy transferred into their gut bacteria, though none of the gene transfers occurred during the course of the study. In volunteers with complete digestive tracts, no recombinant DNA was found.[51] Anti-GM campaigner Jeffrey M. Smith commented on the results by stating:

"This transgene was stable inside the bacteria and appeared to produce herbicide-tolerant protein... In the only human feeding study ever conducted on GM crops, long standing assumptions that genes would not transfer to human gut bacteria were overturned. The findings should prompt immediate comprehensive follow-up tests to determine the implications for health among both the general population and at-risk groups."[52]

[edit] Allergies

In the mid 1990's Pioneer Hi-Bred tested the allergenicity of a transgenic soybean that expressed a Brazil nut seed storage protein in hope that the seeds would have increased levels of the amino acid methionine. The tests (radioallergosorbent testing, immunoblotting, and skin-prick testing) showed that individuals allergic to Brazil nuts were also allergic to the new GM soybean.[53] Pioneer has indicated that it will not develop commercial cultivars containing Brazil nut protein because the protein is likely to be an allergen.[54]

[edit] See also

[edit] References

  1. ^ Kang JX et al. (2007). "Why the omega-3 should go to market". Nature Biotechnology 25 (5): 505–506. doi:10.1038/nbt0507-505. http://www.nature.com/nbt/journal/v25/n5/full/nbt0507-505.html. Retrieved on 2009-03-29. 
  2. ^ Fiester, A. (2006). "Why the omega-3 piggy should not go to market". Nature Biotechnology 24: 1472–1473. doi:10.1038/nbt1206-1472. http://repository.upenn.edu/cgi/viewcontent.cgi?article=1053&context=bioethics_papers. Retrieved on 2009-03-29. 
  3. ^ Lai L et al. (2006). "Generation of cloned transgenic pigs rich in omega-3 fatty acids". Nature Biotechnology 24 (4): 435�436. doi:10.1038/nbt1198. http://pmbcii.psy.cmu.edu/evans/2006_Lia.pdf. Retrieved on 2009-03-29. 
  4. ^ Guelph Transgenic Pig Research Program: EnviropigTM an environmentally friendly breed of pigs that utilizes plant phosphorus efficiently. November 04, 2005.
  5. ^ NRC. (2004). Safety of Genetically Engineered Foods: Approaches to Assessing Unintended Health Effects. National Academies Press. Free full text.
  6. ^ a b Martineau, Belinda (2001). First Fruit: The Creation of the Flavr Savr Tomato and the Birth of Biotech Foods. McGraw-Hill. pp. 269. ISBN 978-0071360562. 
  7. ^ FDA Consumer Letter (September 1994): First Biotech Tomato Marketed
  8. ^ GEO-PIE Project - Cornell University[1]
  9. ^ Shaista Naqvi, et al. Transgenic multivitamin corn through biofortification of endosperm with three vitamins representing three distinct metabolic pathways PNAS April 27, 2009.
  10. ^ [http://www.ctahr.hawaii.edu/oc/freepubs/pdf/NPH-1.pdf Richard M. Manshardt ‘UH Rainbow’ Papaya: A High-Quality Hybrid with Genetically Engineered Disease Resistance. Cooperative Extension Service/CTAHR, University of Hawaii at Manoa.]
  11. ^ [http://www.foodsafety.gov/~lrd/biotechn.html U.S. Food and Drug Administration Center for Food Safety and Applied Nutrition, Biotechnology of Food. FDA Backgrounder: May 18, 1994.]
  12. ^ Amflora - A star(ch) is born: Amylose and Amylopectin - two sides to one potato.
  13. ^ Rapeseed (canola) has been genetically engineered to modify its oil content with a gene encoding a "12:0 thioesterase" (TE) enzyme from the California bay plant (Umbellularia californica) to increase medium length fatty acids, see: [2]
  14. ^ File:Http://www.geo-pie.cornell.edu/crops/enzymes.html GE Enzymes and Microorganisms
  15. ^ Need a more specific citation for this data than the ISAAA homepage.
  16. ^ Economic Impact of Genetically Modified Cotton in India
  17. ^ Comparing the Performance of Official and Unofficial Genetically Modified Cotton in India
  18. ^ Genetically Modified Foods and Organisms
  19. ^ Genetic Engineering: The Future of Foods?
  20. ^ Adoption of Genetically Engineered Crops in the U.S. USDA ERS July 14, 2006
  21. ^ Press Releases 2008
  22. ^ Organic Farming can Feed The World!
  23. ^ Trade barriers seen in EU label for bio-engineered ingredients. (Regulatory and Policy Trends). Business and the Environment 13.11 (Nov 2002): p14(1).
  24. ^ a b northwestern.edu Northwestern Journal of Technology and Intellectual Property Paper on: "Consumer Protection" Consumer Strategies and the European Market in Genetically Modified Foods Quote: The recent Trans Atlantic Consumer Dialogue (TACD) Statement on the WTO decision makes this clear: "clearly consumers' preference for non-GM food is the true engine of the market collapse for American crops." and For instance, Evenson notes that the politicization of GMOs is not merely a question of labeling as information, but unlabeled GM products as catalysts in the "globalization backlash."
  25. ^ a b CBC Identifying genetically modified products. Quote: Yet as seen in this report from CBC's Marketplace, no such labeling law exists in Canada despite numerous surveys indicating up to 90 per cent of Canadians want mandatory labeling of GM food. Canada's leading national consumer group does not support mandatory labeling. It appeared to reverse its stance on December 3, 2003: http://www.consumer.ca/1626
  26. ^ [3]
  27. ^ Raney, Terri, and Prahbu Pingali. "Sowing A Gene Revolution." Scientific American September 2007. 11 September 2008 < http://www.sciam.com/article.cfm?id=sowing-a-gene-revolution>.
  28. ^ Lappe FM, Collins J, Rosset P, and Esparza LFrances Moore Lappé ; Joseph Collins; Peter Rosset. With Luis Esparza. (1998). World Hunger: Twelve Myths. Grove Press. pp. 224. ISBN 978-0802135919. 
  29. ^ Boucher Dedited by Douglas H. Boucher. (1999). The Paradox of Plenty: Hunger in a Bountiful World. Food First. pp. 342. ISBN 978-0935028713. 
  30. ^ Valley, Paul. Strange fruit: Could genetically modified foods offer a solution to the world's food crisis? The Independent, 18 April 2009.
  31. ^ a b James Randerson interviews biologist Arpad Pusztai | Education | The Guardian
  32. ^ http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T1B-3XYFJJ5-H&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=bcb8fc698259a4c41bc16bee8bc629c3
  33. ^ Ewen SW, Pusztai A (October 1999). "Effect of diets containing genetically modified potatoes expressing Galanthus nivalis lectin on rat small intestine". Lancet 354 (9187): 1353–4. doi:10.1016/S0140-6736(98)05860-7. PMID 10533866. 
  34. ^ http://www.ers.usda.gov/Data/BiotechCrops/ US Department of Agriculture, Economic Research Service. Adoption of Genetically Engineered Crops in the U.S. July 2, 2008
  35. ^ Economic Impact of Transgenic Crops in Developing Countries
  36. ^ Zambia Allows Its People To Eat
  37. ^ The Peninsula On-line: Qatar's leading English Daily
  38. ^ World Environment News - Planet Ark
  39. ^ Venezuela: Chavez Dumps Monsanto - Social and Economic Policy - Global Policy Forum
  40. ^ Home
  41. ^ Agriculture Department Probes Rice Flap: NPR
  42. ^ United States General Accounting Office, Report to the Chairman, Subcommittee on Risk Management, Research, and Specialty Crops, Committee on Agriculture, House of Representatives. Information on Prices of Genetically Modified Seeds in the United States and Argentina. January 2000
  43. ^ a b Munzer, Stephen R. (2006). Plants, Torts, and Intellectual Property. Oxford University Press. pp. 1-30. 
  44. ^ a b Federal court of Canada. Monsanto Canada Inc. v. Schmeiser Date: 20010329 Docket: T-1593-98 Retrieved 26 March 2006.
  45. ^ Schubert, Robert: "Schmeiser Wants to Take It to The Supreme Court", CropChoice News, September 9, 2002
  46. ^ Kumar, G. B. Sunil; T. R. Ganapathi, C. J. Revathi, L. Srinivas and V. A. Bapat (October 2005). "Expression of hepatitis B surface antigen in transgenic banana plants". Planta 222: 484–493. doi:10.1007/s00425-005-1556-y. http://www.springerlink.com/content/j28573pu42212114/. 
  47. ^ van Beilen, Jan B.; Yves Poirier (May 2008). "Harnessing plant biomass for biofuels and biomaterials:Production of renewable polymers from crop plants". The Plant Journal 54 (4): 684–701. doi:10.1111/j.1365-313X.2008.03431.x. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-313X.2008.03431.x. 
  48. ^ Proteomic profiling and unintended effects in genetically modified crops, Sirpa O. Kärenlampi and Satu J. Lehesranta 2006
  49. ^ Hierarchical metabolomics demonstrates substantial compositional similarity between genetically modified and conventional potato crops, G S Catchpole and others PNAS October 4, 2005 vol. 102 no. 40 14458-14462
  50. ^ http://www.gao.gov/new.items/d02566.pdf US GAO. "Genetically Modified Foods: Experts View Regimen of Safety Tests as Adequate, but FDA's Evaluation Process Could Be Enhanced." GAO-02-566 Genetically Modified Foods,
  51. ^ Netherwood et al., "Assessing the survival of transgenic planic plant DNA in the human gastrointestinal tract," Nature Biotechnology 22 (2004):2.
  52. ^ Smith, Jeffrey. Genetic Roulette: The Documented Health Risks of Genetically Engineered Foods, p.130, 2007
  53. ^ Julie A. Nordlee, "Identification of Brazil-Nut Allergen in Transgenic Soybeans," New England Journal of Medicine, 334 (1996):688-692.
  54. ^ Streit, L.G., L.R. Beach, J.C. Register, III, R. Jung, and W.R. Fehr. 2001. Association of the Brazil nut protein gene and Kunitz trypsin inhibitor alleles with soybean protease inhibitor activity and agronomic traits. Crop Sci. 41:1757–1760.

[edit] External links

Cons and Pros of GM food.

Sister project Wikibooks has a book on the topic of

[edit] Suggested Reading

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