Selective Breeding + Genetic engineering

• What is selective breeding

  Artificially selecting the plants/animals to breed for the desired characteristics
• What would be the desired characteristics in plants

  • Disease resistance
  • High yield
  • Large/unusual flowers (aesthetic reasons)
• What would be the desired characteristics in animals

  • Animals that produce lots of milk/meat
  • Chickens laying large eggs
  • Domestic dogs with gentle nature
  • High yield
• What are the stages of selective breeding

  • Select individuals with desired characteristics
  • Breed them together
  • Pick offspring with best characteristics
  • Breed them together
  • Repeat for several generations so the characteristics become common in the population
• What are the benefits of selective breeding in agriculture

  • Cattle have better characteristics
  • Like large in size or high yield
• What are the benefits of selective breeding in medical research

  • Studies about alcohol included breeding rats based on their preference for alcohol
  • To study behaviour + brain function
• What are the risks of selective breeding

  • Reducing genetic variation -> inbreeding
  • Genetic disorders (from inbreeding)
  • If new disease arises -> less chances of resistant alleles
• What is genetic engineering

  Modifying an organism's genome to introduce desirable characteristics
• How is genetic engineering used in agriculture

  • Crops genetically modified to be resistant to herbicides
  • So farmers can kill weeds without harming their crops
  • GM crops -> bigger + more fruit
• What are the concerns with genetically modified crops 


  • Transplanted gene may get into other species
  • Weeds may also be weed resistant
  • Don't know the impact of GM crops on human health
• How is genetic modification used in medicine

  • Bacteria genetically engineered to produce human insulin
  • Transferring genes into animals like cows
• How does transferring genes into animals help us

  • Human antibodies for illnesses like cancer can be extracted from GM milk
  • Some animals have been GM so their organs can be used for human transplant
• What are the concerns of using GM in medicine

  • Hard to predict effect
  • Many GM embryos don't survive or suffer with health problems later on in life