Genetic Engineering

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• Genetic Engineering
• Drawbacks
• Opponents emphasize failures of technology,
  potential environmental harm
• Frankenfood
• Farmageddon
• Harm to native species through competition
• Transgenic organisms could be superior
  competitors
• Potential route to extinction for native species
• Damage to beneficial insects
• Ex - Some evidence that ladybugs and lacewings
  suffer (shorter lifespan, reduced reproduction)
  when fed aphids and caterpillars that had fed on
  GM potatoes and corn, respectively
• Damage to soil community
• Certain GM crops could reduce activity of soil
  fungi and microbes
• Negative impact on nutrient cycling in the soil
• Release of resistance genes
• Could potentially lead to super weeds if
  resistance genes get transferred to weedy species
• Could damage natural communities and exacerbate
  weed control problems
• Upset natural balance of ecosystems
• Could result from release of GMOs or
  hybridization between GMOs and native species

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• Genetic Engineering
• Trends
• gt100 GM agricultural plants approved for growth
  in the U.S.
• Most designed to
• Reduce pest damage
• Confer resistance to herbicides, pesticides,
  viruses, other pathogens
• Reduce crop spoilage

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Phenotypes of crop plants field tested in the US
in 2001
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• Genetic Engineering
• Trends
• US grows 50 of GM crops worldwide (acreage
  basis)
• Other major growers of GM crops
• Argentina
• Brazil
• Canada
• India
• China
• Globally, acreage planted with GM crops
  increasing steadily
• 22 of cultivated land planted with GM crops in
  2002
• Soybeans, corn, cotton, canola most important

http//www.agbios.com/dbase.php
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http//www.isaaa.org/kc/cropbiotechupdate/default.
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http//pewagbiotech.org/resources/factsheets/displ
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http//pewagbiotech.org/resources/factsheets/displ
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• Genetic Engineering
• Trends
• US grows 2/3 of GM crops worldwide (acreage
  basis)
• Other major growers of GM crops
• Argentina
• Brazil
• Canada
• India
• China
• Globally, acreage planted with GM crops
  increasing steadily
• 22 of cultivated land planted with GM crops in
  2002
• Soybeans, corn, cotton, canola most important

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670 million acres under cultivation worldwide in
2002
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• Genetic Engineering
• Examples
• Bollgard and Bollgard II Cotton
• Both strains express insecticidal protein
  isolated from Bacillus thuringiensis (Bt)
• Safe Farmers can spray with Bt toxin and still
  label produce as organic
• Low toxicity to most non-target organism types
• Low persistence breaks down readily
• Bollgard II has stacked traits to enhance
  effectiveness
• Controls bollworms, budworm
• Year 2000 United States averages
• Cotton fields planted with Bollgard sprayed 3.9
  times less often vs. conventional fields
• Reduced total pesticide use by 2.7 million pounds
• Pest control cost less - 15.43/acre
• Higher production - 37 pounds/acre
• Higher profit - 39.86/acre
• Concern Development of resistance by insect
  pests

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• Genetic Engineering
• Examples
• Golden Rice
• GM rice containing genes that produce
  beta-carotene
• Can be converted to vitamin A
• Vitamin A deficiency (VAD) may cause weakened
  immune systems, partial to total blindness, and
  increased chance of death
• VAD causes 350,000 cases of blindness and has
  been linked to 1 million deaths each year
• Highly controversial
• Proponents
• Reduce incidence of blindness and other VAD
  related health disorders
• 1/2 lb of rice/day will keep VAD symptoms away
• Opponents
• Nutritional deficiencies will prevent people from
  absorbing beta-carotene from rice
• Concentrations of beta-carotene in rice are low,
  and an average woman would need to eat 16 lbs of
  golden rice a day to get 100 of daily
  requirement
• Alternatives like leafy green vegetables or
  unpolished rice are better, cheaper sources of
  vitamin A
• Western corporations are trying to control rice
  production

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• Genetic Engineering
• Benefits and Risks
• Benefits
• Accelerated improvement of crop strains
• Elevated yields, either per plant or per acre
• Usually involves inserting growth factor
• Plants grow larger, faster or both
• Con Accelerated growth may alter chemical
  composition ? Allergies, digestive problems, etc.
• Accelerated maturation process
• Increased yield per acre, more crops per year
• Con Plants produce different compounds at
  different life stages
• Young plants tend to produce more irritants and
  toxins (self defense)
• Potential to cause digestive or allergic problems

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• Genetic Engineering
• Benefits and Risks
• Benefits
• Increased resistance to disease, pests, toxins
• Reduced losses ? Greater yield
• Reduced application of chemicals
• Con Potential transfer of resistance genes to
  weedy plant species through pollination
• Less problematic in areas where crop plants dont
  have wild relatives
• Con Development of resistance in pests
• Increased longevity of harvested produce
• Resistance to spoilage
• Ex Potato engineered with bacterial gene for
  antifungal properties
• Helps potatoes to stay in storage without rotting
• Con Chemicals that resist decomposition likely
  to be more difficult to digest

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• Genetic Engineering
• Benefits and Risks
• Benefits
• Increased resistance to cultural extremes
• Ex Insertion of Arctic flounder antifreeze
  protein genes into strawberry
• Confers greater frost resistance and better fruit
  storage properties
• Con Potential transfer of antifreeze genes to
  weedy plant species
• Increased nutritional value
• Ex High starch potato that absorbs less oil
  when cooking (low fat potato chips)
• Ex Canola oil (Laurical) with healthier
  composition
• Con Unknown effects of eating modified foods
• Ex Insertion of Brazil nut gene into soybeans
  to increase protein content
• Many people allergic to Brazil nuts

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• Genetic Engineering
• Benefits and Risks
• Benefits
• Reduced dependence on chemical fertilizers
• American farmers spend gt12 billion a year on
  chemical fertilizers
• 50 or more of fertilizer applied to crops is not
  absorbed and enters runoff ? water pollution
• Insert genes from plants that carry out nitrogen
  fixation
• Con Transfer of nitrogen fixation to weeds
  could be disastrous

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• Genetic Engineering
• Benefits and Risks
• Risks
• Unexpected effects
• May or may not be beneficial
• Ex Klebsiella planticola (soil bacterium)
  engineered to transform plant residue into ethyl
  alcohol (fuel)
• GM strain in soils produced EtOH, leading to
  poisoning of grasses and decrease in populations
  of beneficial mycorrhizal fungi
• Ex Pseudomonas putida (bacterium) engineered to
  degrade 2,4-D (herbicide)
• Breakdown products highly toxic to fungi,
  including mycorrhizae
• Ex Bacillus thuringiensis (Bt) toxin may bind
  to soil particles, slowing degradation and
  maintaining toxicity for longer than expected