greek.doctor

15. Genetically modified organisms

Genetically modified organisms – GMO

  • Definition: An organism whose genetic material has been altered using genetic engineering techniques
    • Not necessarily with advanced machines and stuff
    • Selective breeding is also a form of GMO
  • Genes can have been transferred within the same species, across different species and even across biological kingdoms.
  • New genes can be introduced, or endogenous genes can be enhanced, altered or disabled
  • Examples
    • Spider goat
      • A GMO goat that received a spider-silk producing gene.
      • They produced spider silk in their milk
    • Crops
      • Crops are genetically modified to
        • Give higher yields
        • Need fewer antibiotics
        • Be more resistant to infections or drought
      • Almost all crops in the western world today is genetically engineered in some way
      • Especially corn, soy, potato, rice
    • E. coli
      • E.coli are genetically modified to produce insulin and growth hormone for pharmaceutical companies
    • Oxitec
      • Oxitec is a company that produced GMO mosquito that bred with natural mosquito, but their offspring died due to a lethal gene
      • This could decrease the population of mosquitoes
    • AquAdvantage salmon
      • A GMO salmon with different growth hormone gene
      • This salmon grows the whole year, not just during spring and summer
    • Golden rice
      • Rice plants genetically modified to produce rice with more β-carotene
      • Invented to reduce vitamin A deficiency is deficient populations
  • Recombinant vaccines
    • Certain vaccines are recombinant, i.e. the DNA for an antigen is inserted into a bacterium
    • This produces many copies of the antigen, which can be used in a vaccine
  • Edible vaccines
    • Crops like potatoes can be genetically engineered to produce (non-harmful) antigens from infections, which the immune system can create immunity against

Potential harmful effects

  • Eosinophilia-myalgia syndrome
    • A condition that affected many people who took GMO-produced tryptophan supplements
    • The tryptophan supplements were contaminated with an unknown toxin, causing eosinophilia and myalgia
  • Bt toxin
    • Many crops are genetically engineered to produce Bt toxin, a toxin that kills insects that feast on the crops
    • This is used to decrease the amounts of pesticides necessary to maintain a crop
    • Bt toxin may be toxic to humans
      • May damage intestinal cells
      • May promote growth of H. pylori
  • Glyphosate
    • Almost 80% of the world’s crops are GMO’d to tolerate glyphosate
    • Glyphosate is a herbicide which might cause kidney damage in humans
    • The use of glyphosate has skyrocketed after GMO-ing crops to tolerate it became possible

Labelling of GMO

  • In USA – GMO does not have to be labelled
  • In EU
    • All intentional GMO must be labelled
    • Unintentional GMO is not labelled, unless it affects for more than 0.9% of the food

Horizontal gene transfer

  • Exchange of genetic material between organisms without producing a new offspring
  • Examples
    • The 2016 World Food Prize – genes were horizontally transferred from a bacterium to the genome of a sweet potato
    • Amflora – a GMO potato which produced only amylopectin and no amylose, unlike normal potatoes
      • It also contains a gene for antibiotic resistance.
      • If consumed, bacteria in our gut could acquire these resistance gene by horizontal gene transfer