Genetic Engineering

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• Genetic Engineering
• Advantages
• Greater agricultural yields
• More food production per acre could
• Reduce area needed to support existing population
• Support future population growth
• Ex European corn borer destroys 7 of annual
  corn harvest worldwide
• Modified corn resistant to ECB could eliminate
  this loss
• Extra corn 7-10 mmt (enough to feed 60 million
  people)
• Reduced herbicide use
• Wheat, corn, soybeans, cotton, sugar beets,
  alfalfa, etc. engineered to be resistant to
  certain herbicides (e.g. Roundup)
• Farmers can spray crops with less herbicide to
  kill weeds
• Ex Soybeans Reduction of pesticide use by
  10-40 from 1996-1997
• Reduced pesticide use
• Crop plants can be engineered for resistance to
  certain pesticides
• Ex Insect resistant cotton planted in Alabama
  led to an 80 reduction in use of insecticides on
  cotton from 1996-1997
• Environmentally beneficial tasks
• Ex Bacteria engineered to degrade petroleum
  rapidly can be used to clean up oil spills

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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 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 harm non-GM agriculture, including organic
  farming through pollen drift
• 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
• 125 GM agricultural plants approved for growth in
  the U.S. (ISAAA)
• Most designed to
• Reduce pest damage
• Confer resistance to herbicides, pesticides,
  viruses, other pathogens
• Reduce crop spoilage

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Genetically modified crop traits tested in
developed countries, 19872000
Huang et al. 2002 Nature 418, 678-684
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• Genetic Engineering
• Trends
• US grows 48 of GM crops worldwide (acreage
  basis)
• 2011 corn 88, cotton 90, soy 94 GM
• Other major growers of GM crops
• Brazil
• Argentina
• India
• Canada
• China

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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
• Examples
• Future GM crops
• SmartStaxTM corn
• Pest resistant, herbicide tolerant
• Bt rice
• Pest resistant
• High omega-3 soybeans
• Enhanced nutrition
• RR Sugarbeets
• Herbicide tolerant
• 2007 lt10 of US
• 2009 95 of US
• Blue roses
• Ornamental

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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