Genetically Modified Organisms

Transcription

1 Genetically Modified Organisms 1 Genetically Modified Organisms! Farmers have been genetically modifying plants for 1000s of years! Modern technology allows for the insertion of desirable genes into target organism genomes (transgenics) 2 Agriculture and Agri-Food Canada/ Canadian Food Inspection Agency! There is a continuum Plant cultivation/animal husbandry Selective breeding Intra-specific gene transfer Inter-specific gene transfer 3 1

2 From Canadian al Protection Act! Biotechnology: The application of science and engineering in the direct or indirect use of living organisms, or parts or products of living organisms in their natural or modified forms Very general, applies to all processes and products from microbes to humans 4 Genetically Modified Organisms! In Canada, a GMO doesn t exist: Organism with Novel Traits: All organisms with traits that do not exist in the natural varieties This applies to organisms created by traditional methods of selection Most of our food (microbes, plants, animals) are currently genetically different from their natural cousins See the Canadian Food Inspection Agency Website: 5 National Evaluation of GMOs! As a function of their inherent properties Ex. Canada Control is based on the product, not the process! As a function of their mode of production Ex. USA Process, not the product! As something completely different Ex. EU 6 2

3 Confusion Surrounding Regulation! Different processes are often confused with one another Ex. Herbicide-resistant Canola coming from Canada (GMO) are banned in the UK, but not those coming from Australia (conventional) Ex. Whole organisms and derived products are often considered as equivalent - tomatoes (intact DNA) vs. paste (denatured DNA) Some refined products contain no genes or protein products (oils, sugars etc.) 7 Why Modify Organisms?! 1) Agriculture A) improve food quality/quantity B) expand food production C) resistance/tolerance to insects D) resistance/tolerance to herbicides! 2) Public Health Production of vaccines or protein products (ex. Insulin, growth hormones)! 3) Forestry Production of tree varieties resistant/tolerant to pathogens or of increased quality (ex. Lignin production, pollution tolerance)! 4) Other Industrial biomaterials, environmental rehabilitation organisms, microbial pesticides or fertilizers 8 History of GMOs! First products: bacterial gene insertions to create human protein products Insulin Growth hormones No societal resistance whatsoever! First products intended for human consumption: Plants resistant to pesticides GMO tobacco in field studies from

4 Agricultural Use of GMOs! Make better plants Traits associated with yield (seed quality, early maturation, nitrogen fixation etc.) or with environmental tolerance (dessication, coldhardiness etc.) are often multi-gene complexes, therefore molecular techniques are too complicated! Pesticide resistance: Traits for resistance are often associated with only one gene in particular! Pest control Bacillus thuringiensis easy to insert through bacterial cloning (Agrobacterium tumefasciens) 10 Future GMOs! Nutraceuticals Medicinal properties Functional foods Added value! Transgenic animals Milk with added nutrition/medicines Less susceptible to disease Limit pollution from manure Faster growing, more hardy! Plants tolerant to wider range of conditions Dessication, salt, better PS 11 Concerns over GMOs! 1) Subjective Ethical, political, theistic, social, economic!! 2) Rational/scientific A) poses no danger upon consumption Ex. Human or animal food B) poses no danger to the environment Ex. Perturb ecological processes Ex. Resistance 12 4

5 Concerns over GMOs! Much confusion, ignorance and disinformation exists! Most people lack the basic understanding required to discuss the topic Ex. a UK poll demonstrated that 60% of respondents did not realize that non-gmo tomatoes also contained genes! Other problem: there is no consensus on the definition of a GMO 13 Concern Over GMOs! Neoliberal out-sourcing to private market forced biotech into hands of multi-nationals in 80-90s! Public mistrust over incentives of companies for safety over profit! Blending of arguments between regulation of food products and scientific potential of biotech 14 Non-scientific Concerns! 1) over the process Unnatural, playing God Due to molecular homology we already share most of our genes across very distant taxa! what s one more? For non-food GMOs (insulin or cystic fibrosis enzyme from bacterial gene insertion and cloning) Most people are ok with this form of GMOs so they are not inherently against the process itself! 2) over the products (potential) Creating monsters Haven t yet seen any problems 15 5

6 Potential Risks of GMOs! Risk: probability that something poses a danger! To public health: Increase in toxicity, allergens or decrease in nutritional quality Risk for toxicological profile is calculated using a) biological activity of the product, b) the frequency, intensity and duration of exposure 16 Potential Risks of GMOs -! 1) Modification of the rhizosphere by gene transfer (lateral transfer common in bacteria) 17 Potential Risks of GMOs -! 2) Diffusion of GMOs into the environment Super-Weeds could become invasive In W Canada, natural populations of Canola have become resistant to herbicides Margin of security: artificial selection has weakened hardiness of agricultural seeds and crops Herbicide resistance not really an issue in nature, other forms of tolerance could be problematic HT plants could re-invade agriculture 18 6

7 Potential Risks of GMOs -! 2) Diffusion of GMOs into the environment Gene flow between GMO populations and natives 12/13 of the most important plant crops are grown in proximity of their wild cousins (ex. wheat, rice, corn, soya, cotton, barley) How to control? Dispersal by pollinators, seeds! Contaminate non-target foods Monarchs on Asclepiad 19 Potential Risks of GMOs -! 2) Diffusion of GMOs into the environment Ex: Starlink Corn (B.t.) Protein product Cry9C (similar to many allergens) Banned from human consumption Approved pour industrial nonfood uses, animal feed and the production of grain Contamination has been documented in food products (requires recalls, inquiries, compensations etc.) 20 Potential Risks of GMOs -! 3) Risks of insects developing resistance to GMOs Many species already show B.t. resistance in laboratory One case observed in nature: Diamond-backed moth (Plutella xylostella) on crucifers in FLA and NY! Selection pressures are more intense because expression is continuous in GMOs 21 7

8 Potential Risks of GMOs -! Strategies to reduce the potential for resistance Mixed cultures Non-GMO refugia around GMO crops EPA (2000): no more than 80% of a crop can be GMO B.t. 22 Potential Risks of GMOs -! 4) Negative effects on biodiversity Agriculture is already among the human activities that leads to biodiversity losses UNEP: biodiversity loss has been accelerating since 1600, has reached 100x the natural rate A) genetic homogenization of parental stocks B) effects on non-target organisms and up the food chain 23 Potential Risks of GMOs! Pleiotropic effects Genes rarely act in isolation Many interactions exist between genes and the genome Ex. Regulators of the expression of other genes (amplitude) Ex. Initiators or terminators of the expression of other genes 24 8

9 Potential Advantages of GMOs -! Reduction of pesticide use Australia: noticed a reduction of 50% in 2 years with B.t. cotton USA ( ): reduction of 21% with B.t. cotton USA: reduction of 10-30% with GMO soya USA in general (FDA): pesticides were reduced in 7/12 regions, but not in the other 5/12 25 Potential Advantages of GMOs -! Why no reduction in 5/12 regions? Herbicide resistant GMOs created to be specifically used with a particular pesticide Ex. Monsanto Round-up Ready plants can only be used with glyphosate 26 Potential Advantages of GMOs - Target Species Source: G Frisvold, University of Arizona 27 9

10 Scrutiny of GMOs! GMO creation is under rigorous and elaborate scrutiny at every step Many more varieties are created by genetic engineering than by conventional methods We have no idea what genes are created by mutation but we know exactly with gene transfer 28 Potential Risks of GMOs! Have been growing experimentally for years Thousands of generations of GMO plants! GMO products have been consumed by humans since 1994! No pronounced effect has been observed in public health or on ecosystem functioning to date! When unintended effects have been discovered, those strains have been scrapped Ex. Beans with nut gene 29 Evaluation of GMO Risks! GMO plants must be exactly the same as cousin plant, all respects related to health and safety! Must be considered Substantially Equivalent Agricultural, environmental and public health parameters 30 10

11 Global Trends in GMO Use 31 USDA 32 Recent Trends 33 11

12 Recent Trends 34 References! Stephenson and Soloman Pesticides and the. CNTC Press.! Leiss and Powell. Mad Cows and Mother s Milk. McGill-Queens U Press! McHughen, A Pandora s picnic basket. Oxford University Press 35 12