Genetically Modified Organisms


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Genetically Modified Organisms

  1. 1. Objectives: Define Genetically Modified Organisms & Biodiversity Identify threats to Biodiversity Enumerate advantages & disadvantages of GMO Cite examples of GMO
  2. 2. Definition of Terms Genetically Modified Organisms• Genetically Modified Organisms are the ones in which the genetic material (DNA) has been altered in such a way as to get the required quality. This technology is often called „gene technology‟, or „recombinant DNA technology‟ or „genetic engineering‟ and the resulting organism is said to be „genetically modified‟, „genetically engineered‟ or „transgenic’ (Sabha, 2009).
  3. 3. Definition of Terms Biological Diversity• Biological diversity as a concept refers to the variety and variability of living organisms (Millenium Ecosystem Assesment, 2005).
  4. 4. Alteration and loss of the habitats
  5. 5. Introduction of exotic species and genetically modified organisms
  6. 6. Pollution
  7. 7. Climate change
  8. 8. Overexploitation of resources
  9. 9. Threats to Diversity Further signs of stress in the global biodiversity is that the population size or range (or both) of the majority of species across a range of taxonomic groups is declining (MEA 2005). Currently, estimated species extinction rates are 1,000 times higher than background rates typical of the planet‟s history (MEA 2005; Lövei 2007). A total of 10–30% of mammal, bird, and amphibian species are currently threatened with extinction (Secretariat CBD 2006).
  10. 10. Advantages of GMO Increase in agricultural activity• This would be an important benefit, in a world in which demand on lands is increasing. Commercial aquaculture also utilises GM technology, to increase species growth and adaptability. (Royal Society of Canada, 2001)
  11. 11. Advantages of GMO Carbon-storage and climate change• Benefits may accrue from the use of GM trees. As disputes concerning the value of “carbon sequestration” within the climate change analysis have been generally resolved, the use of these trees is generally expected, and some has already begun. Recent research by WWF shows that since 1988 there have been 184 GM tree field trials globally (Asante- Owusu, 1999).
  12. 12. Advantages of GMO Minimisation of pesticide use• Here also, the environmental benefit can be significant, given the role of agricultural pesticides in species extinctions, and in the contamination of critical ecosystems.
  13. 13. Advantages of GMO “Edible vaccines”• It has been noted that diarrhoea caused by bacteria is one of the leading sources of infant mortality, particularly in the developing world, where obtaining injections in time may be difficult. Recent animal studies involving transgenic bananas and tomatoes, which produce vaccines against cholera or to address specific disease agents responsible for many prevalent kinds of diarrhoea, are producing encouraging early results. In future, such food vaccines might also be able to suppress auto-immunity (a condition in which the body‟s defences mistakenly attack normal uninfected tissue). (Arntzen, 1995)
  14. 14. Advantages of GMO Intentionally “invasive” uses• GM insects have been developed, with a variety of objectives, such as to reduce populations of insect pests whose damage to agricultural crops is particularly high, and to inhibit negative traits in “wild” insects (including the trait which allows anopheles mosquitoes to host the malaria parasite.) (Zitner,2001)
  15. 15. DISadvantages of GMO Genetic contamination/interbreeding• GMOs could possibly interbreed with other sexually compatible species within the area in which the GMOs were introduced. Some experiments have shown that the rate of cross-pollination between conventional and GM varieties of potatoes are generally low and become negligible when the separation distance exceeds 10 metres (Rogers, 1995).
  16. 16. DISadvantages of GMO Genetic contamination/interbreeding• By contrast, Danish field trials have shown that oilseed rape modified for herbicide tolerance can easily cross with wild Brassica species such as wild mustard (Chevre, 1997). Consequently, cross-pollination between GM and non-GM oil seed rape has been detected at distances of up to 2 km.
  17. 17. DISadvantages of GMOfa Competition with natural species• One trait that is often promoted by GM crop developers is increasing productivity through faster growth. Fast maturation, however, can serve as a significant competitive advantage, which might allow an organism to become invasive (spread into new habitats and cause ecological or economic damage). Even where there is no likelihood that a given GM species will interbreed with wild species in the area, it may out- compete, forcing them into decline and possible extinction.
  18. 18. DISadvantages of GMOIncreased selection pressure on target and non-target organisms• Forty years of empirical evidence from the U.S., Japan, Central America and China demonstrates that the use of the pesticides consisting of Bt toxin (a naturally occurring pesticide, now incorporated in numerous crops for resistance to certain insects) has allowed some agricultural pests (such as the diamond back moth Plutella xylostella) to evolve distinct toxin resistant populations. (Tabashnik, 1994)
  19. 19. DISadvantages of GMO Impossibility of follow-up• One example involves the introduction of barn owls in the Seychelles, to control the population of inadvertently introduced European rats. The owls (natural predators of the rat species in their native surroundings) found other, in some cases endangered, species much easier to catch. They were able to out-compete native species that preyed on these animals, and eventually represented a much more serious threat to the island ecosystem than the rats they were imported to control. (FAO,1993)
  20. 20. DISadvantages of GMO Invasive Alien Species One way to assess the potential invasiveness of GMcrops is through the IPPC‟s (International PlantProtection Convention) Invasive Species and PestManagement risk criteria: • Changes in adaptive characteristics (that may increase the potential for establishment and spread); • Adverse effects of gene transfer/flow (that may result in the establishment and spread of pests, or the emergence of new pests); • Adverse effects on non-target organisms; • Genotypic or phenotypic instability (that could result in the establishment and spread of organisms with new pest characteristics).
  21. 21. Insect Resistance• Crops that have insect resistance represented 16.2 per cent of the global area planted in 2005 (James, 2005). They are often known as Bt crops due to the protein genes that are introduced into a plant following extraction from a bacterium known as Bacillus thuringiensis. This bacterium is found naturally in soil and has been used in organic agriculture for insecticide preparations because it is toxic to specific groups of insects (Prakesh, 2005). Bt kill insects with toxins called insecticidal crystal proteins or delta endotoxins. Delta endotoxins rapidly paralyze the insect‟s digestive system, so damage to the plant stops soon after the insect is exposed to the toxin (Colorado State University Extension, 2010).
  22. 22. Bt Corn• Bt Corn contains Cry1Ab gene which produces delta toxin.
  23. 23. Bt Eggplant• Genes from the bacterium Bacillus thuringiensis has been inserted into the DNA of the eggplant so that it produces a protein called Cry1Ac, which is a toxin. Importantly, there are no commercial food crops with this type of Bt gene. For Cry1Ac, there is concern over its potential allergenicity. Moreover, the Bt toxins in GE eggplant are specifically toxic to Lepidoptera (butterflies and moths), but not all of these are pests (Dr. Janet Cotter, 2011).
  24. 24. Bt Potato• One of the most consequential potato plant pests is the potato beetle (Leptinotarsa decemlineata), which often becomes resistant to chemical insec-ticides. Modified potatoes carrying gene Cry3A originating from bacteria Bacillus thuringiensis were produced to control this beetle. This gene product is a toxic protein formed in leaves of these plants; after ingestion by a potato beetle, it passes on to its intestines and thus causes the death of the pest (Pribylova, Pavlik, Bartos, 2006).
  25. 25. GM Potato• Potato plants resistant to increased soil salt levels were produced by insertion of a gene for glyceralde-hyde-3- phosphate-dehydrogenase (GPD) from oyster mushroom (Pleurotus sajor-caju) into potato plant genome. The effect of the protein was tested by culti-vation of potato plants in sodium chloride containing soil. Whereas GPD-free potato plants died in several days, transgenic plants exhibited a high tolerance to the presence of salts (Jeong et al., 2001).
  26. 26. GM PotatoSource: Toxicity Studies of Genetically Modified Plants by Jose L.Domingo, 2007
  27. 27. Biofortification• It is the adding of essential nutrients, vitamins and metabolites with plants during their growth and development, thereby making these additives more readily available for human/animal consumption.• Recently it was divided into agronomic and genetic fortification. The first one uses soil and spray fertilizers enriched by individual essential elements (eg Fe, Zn and Se). This approach has been adopted with success in Finland for enrichment of crops by Se. On the other hand, the genetic pcfortification present the possibility to enrich food crops by selecting or breeding crop varieties, which enhanced Se accumulation characteristics (Broadley, et. al., 2006).
  28. 28. Golden Rice
  29. 29. Golden Rice• Originally, the scientists who developed the rice had expected grains to be red due to the genes they had inserted. Rice grains were supposed to generate red carotenoids, so-called lycopenes like those found in tomatoes. The authors revealed in their study that the original genes of the plant unexpectedly caused the lycopenes to be converted into yellow carotenoids. The yellow color giving the rice its name (Golden Rice) was the outcome of an unintended reaction, caused by interactions between inserted genes and the genome of the plants (Schaub et al., 2005).
  30. 30. Golden Rice
  31. 31. Golden RiceThe b-carotene in GR is as effective as pure b-carotene in oil and betterthan that in spinach at providing vitamin A to children. A bowl ofapproximately 100 to 150 g cooked GR (50 g dry weight) can provideapproximately 60% of the Chinese Recommended Nutrient Intake ofvitamin A for 6–8-y-old children (Guangwen Tang, Yuming Hu, Shi-anYin, Yin Wang, Gerard E Dallal, Michael A Grusak, and Robert MRussell, 2012).
  32. 32. Control or Chaos? Unwanted and uncontrollable spread of GM plants is a highlyvisible process on a global scale. By the end of 2006, over 100 cases ofconfirmed, unwanted contamination and 26 cases of illegal releaseswere registered (mostly by civil society organisations). A total of 39countries on five continents have been affected, almost twice thenumber of countries that currently grow GM crops. In 2005, there wereseven documented cases of contamination and eight illegal releases. In2006, the number of contamination cases more than doubled to 15.Most prominently, two unapproved GM events were found in rice (aherbicide-tolerant transgene from the USA and a Bt transgene fromChina) – these were detected at the consumer level (in shipmentsintended for human consumption). More problematic is the detection ofplants with GM traits that have not yet been commercialised.
  33. 33. • Due to their reproductiveGlofish biology, fish are relatively simple to genetically modify and have thus been the main focus of GM animal research, with more modified species than all other vertebrates combined. One GM fish is already commercially available in the USA for aquariums – the Glofish, a Zebra danio modified to produce a red fluorescent protein.
  34. 34. Glofish • Transgenic zebrafish contained the gene (dsRed) coding for the red fluorescent protein, originally isolated from the marine sponge Discosoma striata. • Their color is caused by high concentration of red fluorescent protein (RFP) in fish muscle (Gond et. Al., 2003).
  35. 35. AquAdvantage® Salmon• GM salmon that can reach adult size three times faster than their non- GM relatives (IUCN The World Conservation Union).
  36. 36. AquAdvantage® Salmon • Escaped genetically engineered salmon are likely to compete with wild fish, including endangered Atlantic salmon, for habitat, food, and mates (Ford JS and Myers RA. 2008).
  37. 37. AquAdvantage® Salmon• Research published in the Proceedings of the National Academy of Sciences found that the release of just 60 genetically engineered fish into a wild population of 60,000 could lead to the extinction of the wild population in less than 40 generations (Howard RD, DeWoody JA, Muir WM., 2004).
  38. 38. AquAdvantage® Salmon• However, Aquabounty claimed that AAS will be grown as sterile, all-female populations in land-based facilities with redundant biological and physical containment.• As a result, AquAdvantage® Salmon cannot escape or reproduce in the wild and pose no threat to wild salmon populations.
  39. 39. AquAdvantage® Salmon• Six chemicals (folic acid, niacin, vitamin B6, magnesium, phosphorus and zinc) are present in genetically engineered salmon at values that differ by more than 10 percent from conventional farmed salmon, indicating potential food quality differences among the two kinds of fish.
  40. 40. AquAdvantage® Salmon• The omega 3/omega 6 ratio in genetically engineered salmon is more than 12 percent less than in conventional farmed salmon, a difference that could be of interest to seafood consumers looking to maximize omega 3 levels in their own diets.
  41. 41. AquAdvantage® Salmon• Data indicate there may be higher levels of allergy- producing compounds in genetically engineered salmon, meaning the fish may pose a greater food allergy threat. Given the limited sample sizes, more study is needed to definitively rule out this concern.
  42. 42. AquAdvantage® Salmon• Levels of Insulin-like Growth Hormone (IGF-1) are elevated in genetically engineered salmon compared to conventional farmed salmon. The long-term health impacts of this are unclear, but IGF-1 is a known carcinogen.
  43. 43. SynthesisIn general, Biodiversity cannot fully be replace byGenetically Modified Organisms due to thefollowing reasons: firstly, GMO itself may causesalteration to ecological balance; second, there is noany supportive studies which can prove that it mayactually sustain life, the way that the naturalenvironment can; and lastly, there is no perfectassurance that GMO can actually exist for alifetime without a failure with its function.