Genetic Engineering

1

• 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

2

• 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

3

• 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

4

• Genetic Engineering
• Benefits and Risks
• Benefits
• Reduced dependence on chemical fertilizers
• More efficient growth ? lower use of fertilizer
• 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
• Con Transfer of genes for greater growth
  efficiency to weeds could be disastrous
• Con Substitution of dependence on big western
  agribusiness

5

• 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