genetically modified organisms - adam oliver...
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BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment 1
Genetically Modified Organisms
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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)
BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment
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
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BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment
From Canadian Environmental 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
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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
http://www.inspection.gc.ca/plants/plants-with-novel-traits/eng/1300137887237/1300137939635
See the Canadian Food Inspection Agency Website:
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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
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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.)
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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
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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 1986-1989
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Agricultural Use of GMOs ! Make better plants
– Traits associated with yield (seed quality, early maturation, nitrogen fixation etc.) or with environmental tolerance (dessication, cold-hardiness 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)
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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
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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
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! 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
Concerns over GMOs
BIO 4101: Pesticides and the Environment BIO 4101: Pesticides and the Environment
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
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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
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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
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! 1) Modification of the rhizosphere by gene transfer (lateral transfer common in bacteria)
Potential Risks of GMOs - Environment
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! 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
Potential Risks of GMOs - Environment
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! 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
Potential Risks of GMOs - Environment
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! 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 non-
food uses, animal feed and the production of grain
– Contamination has been documented in food products (requires recalls, inquiries, compensations etc.)
Potential Risks of GMOs - Environment
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! 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
Potential Risks of GMOs - Environment
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! 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.
Potential Risks of GMOs - Environment
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! 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
Potential Risks of GMOs - Environment
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! 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
Potential Risks of GMOs
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! Reduction of pesticide use – Australia: noticed a reduction of 50% in 2 years
with B.t. cotton – USA (1998-1999): 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
Potential Advantages of GMOs - Environment
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! 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
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Potential Advantages of GMOs - Environment
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Target Species
Source: G Frisvold, University of Arizona
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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
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! Have been growing experimentally for 35-40 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
Potential Risks of GMOs
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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
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Global Trends in GMO Use
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USDA
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Recent Trends
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Recent Trends
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References
! Stephenson and Soloman. 2007. Pesticides and the Environment. CNTC Press.
! Leiss and Powell. Mad Cows and Mother’s Milk. McGill-Queens U Press
! McHughen, A. 2000. Pandora’s picnic basket. Oxford University Press