Teacher FAQs

Is Genetic Modification (GM) a modern technology and what is meant by ‘classical breeding’?

 

  • Genetic Modification – aka. Transformation, genetic engineering, transgenesis
      • Where cloned genes are transferred into the chromosomal DNA of another organism
  • In one sense, the process of genetically modifying an organism dates back approximately 12,000 years – more commonly known as selective breeding
  • ‘Classical breeding’ consists of crossing organisms, either via genetic recombination or independent assortment - it is ‘blind’ and as such the outcome is unknown
  • A common use of classical breeding was to produce new varieties that have specific properties – e.g. a higher yield
  • First GM of a microorganism – 1973
  • First GM of a broad leaf plant (tobacco, tomato) – 1983
  • Late 1980s, first GM of a narrow-leaved plant (cereal crops)
  • Initial trials used the bacterium, Agrobacterium tumefaciens, which transferred genes for antibiotic resistance into tobacco plants

 

How are the cloned genes inserted into another organism?
  • There are two main methods – Agrobacterium and the ‘gene gun’
  • Agrobacterium
      • Causes crown gall disease to develop in dicotyledonous plants (broad-leaved plants)
      • Galls are large tumour-like swellings caused by the bacterium, a natural pathogen, transferring its DNA into the plants genome
      • The genes, that code for the disease, are found on the Ti (tumour-inducing) plasmid
            • Plasmid – circle of DNA  separate from chromosomal DNA that has the ability to replicate independently – they code for non-essential functions so the bacterium can survive without the plasmid
      • Bacterium transfers its DNA from the plasmid into the host (in this case the potato plant)
      • The genes integrate and transfer the genetic information that causes the gall to form
  • Gene Gun
      • Method involves gold or tungsten micro-particles coated with modified DNA that are propelled into a target cell at a very high velocity by an electrical discharge or compressed helium gas
      • Known as biolistic transfection

 

What are some other uses of Genetic Modification?

Human insulin - 1982

Cheese manufacturing – the enzyme Chymosin, usually extracted from the stomach of calves (http://tinyurl.com/NCBEcheese) 

GM mosquitoes – engineered so the parasite cannot infect the gut and as such is not passed on when the mosquito feeds (http://tinyurl.com/BBCmosquito) 

 

When and where were the first GM crops introduced?
  • Early 1990s, commercial scale field trials in the USA were introduced
  • Between 1986 – 1997, approximately 25,000 GM crop field trials were carried out on over 60 crops with 10 traits in 45 different countries – 72% of which were in the US and Canada
  • Between 1996 – 2002, the total area of GM crops in the USA increased from 1.7 million to 34 million hectares
  • By agricultural standards, the adoption rate was very high for such a new technology
  • Regulatory frameworks – safety and ethical guidelines across the world enforced by government agencies
  • International protocols prohibits misuse of GM organisms for biological warfare

 

What are some of the ethical benefits of growing GM crops?
  • Agriculture
        • Biotechnology offers a prospect of long-term sustainable agriculture to farmers in Third World countries 
        • In other words, feeding the poor
        • Increased yield of crops
        • More efficient use of land – by modifying crops to survive in tough environments e.g. soil with high pH
  • Environment
        • Less chemicals used to control pests
  • Human Health
        • Creation of crops that produce drugs or enriched with vitamins and minerals

 

What are some of the ethical concerns regarding GM crops?
  • Some believe moving genes between organisms is intrinsically wrong
  • Environmental Concerns
        • New plants will become pernicious weeds
        • GM plants will transfer their new genes to their wild relatives or similar crops with unforeseen consequences
        • Plants with introduced genes may lead to the establishment of resistant populations of pest
  • Food Safety
        •  It may be possible for the marker genes e.g. antibiotic resistant genes, to be transferred into other organisms including humans
  • Agriculture
        • Shift towards larger farms and more capital-intensive farming which would favour wealthier farmers in more developed countries – exploitation of the economically weak
        • Leaves people reliant on GM and the biotech companies
  • Financial
        • GM seeds often expensive
        • Accusations that the biotechnology companies are only motivated by the financial incentives
  • Misuse – biological warfare (although there are international protocols prohibiting this)

 

Background on specific videos


What is late blight and why should we be concerned about our potato industry?
  • Late blight caused by water mould Phytophthora infestans 
  • Thrives in wet weather, 60 to 80F and high humidity 
  • Attacks leaves and tubers
  • Most destructive disease to affect potato crops – the fourth largest food crop
  • Annual losses estimated at £3.5 million 
  • Costs £350 per hectare to control the disease
  • Farmers spray crops 10-15 times per season but does not necessarily prevent the disease

Is late blight just a recent problem?
  • No,  it has been a problem at other times in history e.g. the Irish Potato Famine
  • 1845-1852 Ireland experienced the Great Famine – a period of mass starvation
  • Irelands population decrease 20-25%
  • Approx. 1 million people died, 1 million emigrated
  • Loss of potato crops intensified due to social, political and economic factors experienced within the country

What is the aim of this trial?
  • To assess if this approach to crop disease resistance is likely to be successful and if so can be deployed into commercial farming 

How has this GM potato been created?
  • Two genes that give potatoes resistance to the pathogen were taken from wild South American species that are not themselves edible 
  • They also contain another gene resistant against the antibiotic kanamycin
  • Kanamycin is used during the modification process to select plants that also contain the inserted resistance genes

Where is the location of the trial?
  • At the Sainsbury Laboratory at the John Innes Centre in Norfolk (http://tinyurl.com/sainsburylab)  
      • Opened in 1988
  • Area of the trial equals 1000 square metres
  • Over 3 years, 200 square metres will be sown

Who funds this trial?
  • The UK Biotechnology and Biological Science Research Council (BBSRC) supports and funds the use of GM as a lab tool (http://tinyurl.com/BBSRChome) 
  • No commercial funding

What are the potential benefits of producing these potatoes?
  • Reduced use of chemicals to treat the disease
  • Save money
  • Reduce use of tractors etc – carbon dioxide emissions

Do the local residents need to be concerned?
  • Pollen does not usually travel more than 10 metres 
  • Potatoes cannot cross with any other natural species
  • In the unlikely event that GM potatoes did cross with other potatoes any seeds produced would not be saved as they are grown from tubers
 
 
 
 
 
 
 
 

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