medical applications 

• pharmaceuticals - uses bacterial cells to mass produce certain proteins cheaply
  • recombinant genes introduced into bacterial cells
  • used to produce insulin, interferon, growth hormones, erythropoietin
  • atrial peptides - small proteins to treat high blood pressure
  • tissue plasminogen activator - human protein that causes blood clots to dissolve
  • hard/expensive to purify proteins produced by bacterial cells
• genetic therapy - started in 1990 in attempt to fix genetic defects
  • replaces defective gene w/ working copy
• piggyback vaccine - aka subunit vaccines, used against viruses
  • uses DNA of benign vaccinia virus to make vaccines, stimulate immune system
  • DNA vaccine - depends on killer T cells instead of antibodies to stop viruses

agricultural applications 

• limited number of possible vectors for plants
• Ti (tumor-inducing) plasmids - infects broadleaf plants
  • doesn’t infect cereal plants (corn, rice, wheat)
• “Flavr Savr” - has genes that inhibit ethylene production, delaying over-ripening
• nitrogen fixation - converts nitrogen gas to ammonia
  • plants use ammonia to make amino acids
  • nifgenes - found in symbiotic root-colonizing bacteria
  • soil runs out of nitrogen w/o addition of fertilizers
  • problems w/ protecting nitrogenase from oxygen
• herbicide resistance - herbicides used to kill weeds, but can also kill plants
  • glyphosphate - active ingredient that inhibits EPSP synthetase
  • new engineered plants have 20x normal amount of EPSP synthetase, can work even in presence of glyphosphate
• insect resistance - removes need to use so many insecticides
  • uses genes for proteins harmful to insects but harmless to other organisms
  • transgenic plants - plants w/ altered genes, protected from insects that normally feed on them
• “golden rice ” - used to solve problem of lack of iron in diets
  • ferritin gene from beans added to increase iron content
  • gene added to destroy phytate (inhibits iron absorption)
  • gene for sulfur-rich protein added from wild rice (sulfur needed for iron absorption)
  • ordinary rice lacks certain enzymes to finish provitamin A creation
• gene technology replacing natural/artificial selection as means for breeding

risk/regulation - tampering w/ genetics >> possible bad long-term side effects 

• gene modifications make crop easier to grow, improves food itself
• screening for allergy problems done w/ genetically altered foods
• pests become resistant to pesticides faster than to genetically altered defenses
• debates over whether consumers should/need to know about genetically modified foods