Genetic technology and agriculture

Genetically modified plants

• proteins for use in medicine can be produced from genetically modified plants
  • so avoiding  any problem of contamination by animal proteins
• exmples include:
  • vaccines
  • albumin
  • proteins found in breast milk used to treat diarrhoea in infants
• the vast bulk of genetically modified plants are modified to be resistant to herbicides or to insect pests
  • these modifications increase crop yield
• a few crops, such as vitamin A-enhanced rice, provide improved nutrition

Herbicide-resistant crops

• oil seed **** is grown as a source of vegetable oil which is used as:
  • biodiesel fuel
  • a lubricant
  • in human and animal foods
• natural **** seed oil contains undesirable substances in oil that is used in human or animal food
• a hybrid is bred to produce low concentrations of these undesirable substances and was called canola (canadian oilseed low acid), and this name is now often used to mean any variety of oil seed ****
• gene technology has been used to produce herbicide-resistant strain allowing  fields to be sprayed with herbicide after the crop has germinated, killing any weeds that would otherwise compete with the crop for space, light, water or ions
• oil seed **** that is resistant to the herbisides (glyphosate and glufosinate)  is grown in many countries

• glyphosate inhibits an enzyme involved in the synthesis of three amino acids: phenylalanine, tryosine and trytophan
• glyphosate is absorbed by a plant's leaves and is transported to the growing tips
• the amino acids are needed for producing essential proteins, so the plant dies
• various microorganisms have versions of the enzyme involved in the synthesis of the 3 amino acids that are not affected by glyphosate
• the gene that was transferred into crop plants came from a strain of bacterium

• tobacco has been made resistant to two different herbicides: sulfonylurea and dinitroaniline
  • in both cases the genes were taken from other species of plant

The most likely detrimental effects on the envrionment of growing a herbicide-resistant crop are that:

• the genetically modified plant will become an agricultural weed
• pollen will transfer the gene to wild relatives, producing hybrid offspring that are invasive weeds
• herbicide-resistant weeds will evolve because so much of the same herbicide is used

An investigation was carried out to compare invasiveness of normal and genetically modified oil seed **** plants was carried out. Three genetic lines were compared:

• non-engineered oilseed **** 
• two different genetically engineered versions of the same cultivar

• the rates of population incrrease were compared in plants grown in different environments
• the environments differed in for example:
  • presence and absence of cultivattedand uncultivated bacground vegetation
  • presence and absence of various hebivores and pathogens
• there was no evidence that genetic engineering increased the invasiveness of oi seed **** plants
• where differences between the normal and GM plants existed, the GM plants were slightly less invasive than the unmodified plants

• the risk of pollen transfer, by wind or by insects, is real
• safe planting distances should be increased to allow the organic farming industry to maintain its 'GM-free' certification

Gene technology is not…