1. PRESS CONFERENCE
GENETIC MODIFIED FOOD

2. Genetically Modified Food
Mechanism of Genetically Modified Food--GM food (There are totally 2 methods)
Applications of Genetic Modification
Pros and Cons of GM food
News
Government’s action

3. Mechanism of GM Food(1) 1)Isolating/synthesizing the target gene
2)Inserting the target gene into a vector, i.e. an intermediate carrier
3)Transferring the vector containing the target gene into a host cell and cloning the DNA
5) Mixing plant cells with host cells

4. Mechanism1 : Isolating/synthesizing the target gene
The ‘shotgun’ approach, using type II restriction enzyme(restriction endonuclease )
- the enzyme cuts at recognition sites, to obtain a desired gene
- sticky ends or blunt ends produced (there are figures later)
Making a copy of the gene from its mRNA
- poly-T oligomer binds to the complementary poly-A tail of the mRNA
- a single strand of DNA copy formed
- digesting mRNA
- a double-stranded cDNA produced

5. Sticky end and blunt end

6. Mechanism1 : Inserting the target gene into a vector
Step 1) Prepare a target gene with sticky end if it has blunt end
- Short pieces of DNA are joined at the end of the gene
- restriction enzymes cut linkers
Step 2) Prepare the plasmid DNA (a figure later) as vector
- centrifugation
Step 3) Combine the target gene and the plasmid DNA by DNA ligase
- To have the same sticky end, the same restriction enzyme is used to cut the vector

7. Plasmid DNA
Circular DNA(2), which is smaller and lighter than main chromosomal DNA(1)

8. Mechanism1 : Transferring the vector into a host cell (transformation) and Cloning the DNA
Step 1) Adding the plasmid vector into a flask containing culture of a host cell
Step 2) Generating temporary pores on the surface of the host cell
Step 3) Allowing the plasmid vector to enter the host cell
Step 4) Placing the host cell in a dish with nutrients

9. Mechanism1: Mixing plant cells with host cells
Using Agrobacterium tumefaciens or Agrobacterium rhizogenes as vectors
Introducing Ti-plasmid into the plant cells
The whole plant can be regenerated from a transformed leaf disc

10. Summary of the mechanism(1)

11. Mechanism of GM Food(2) Antisense approach
Switching off or turning down (underexpressing) a resident gene in the organism
Antisense RNA is produced

12. Applications of Genetic Modification in Food Production
GM Food
-Tomatoes and tomato paste
-Corn maize
-GM soya beans
GM processing aid
-A kind of GM organism making a product without GM material
GM ingredients in animal feed

13. Benefits of GM food higher yields increased muscle bulk (animals)
the ability to resist disease, pests or chemicals
a prolonged shelf-life
higher nutritional value
reduced allergens
the ability to grow in environments that are usually too hostile.

14. Disadvantages of GM food
Unintended modification of similar species due to cross pollination
Upsetting the ecosystem
Development of super pests
Problems about religious, health, etc
Destroying the normal farming system
Interfering the normal DNA system
Widening the financial gaps between developed and developing countries

15. News about GM food

16. out allergenic proteins regulators should demand
SOURCES: New Scientist (issue 2530)
Letter to the Editor, 17 December 2005
allergenic potential of genetically modified foods (e.g. mouse strains in peas )
Existing tests provide no direct immunological information and cannot rule
out allergenic proteins
regulators should demand
full sequencing of the
transgenic proteins in plants

17. causing a wave of “superweeds” ‘co-existence’ is biologically
SOURCES: ISIS Press Release 16December,2005
Genetically modified DNA from any part of a GM plant can enter the environment unobserved
causing a wave of “superweeds”
‘co-existence’ is biologically
impossible

18. no existing public records of contamination incidents or other problems associated with GM crops
strict rules with liability regulations should be applied by governments to stop the
unauthorized spread of
GM seeds and products
data used by the
Government to approve
GM foods should be
accessed freely

19. Modified animals: 27%(2003) 32%(2004)
SOURCES: BBC News 8 December 2005
Modified animals: 27%(2003) %(2004)
Total experiments: just over 2.85 million
Number of animals used in research: 2.78 million (a rise of 2.1% on 2003 figures)

20. Within three weeks of birth, - 55% of the rats fed on GM soya died
SOURCES: GM Free Cymru [Wales]
Press Notice 25thNovember 2005
Within three weeks of birth,
- 55% of the rats fed on GM soya died
- 9% of the rats died in the control group
mice fed on GM soya experienced a slowdown in cellular metabolism and modifications to liver and pancreas
introduction of genes from a bean variety into a GM pea led to the creation
of a novel protein which
caused inflammation of
the lung tissue of mice.

21. What should HK government do?
Setting up mandatory labelling system for GM food
informing the public the pros and cons of GM foods
building up its own expertise with public health professionals and GM food-related scientists

22. What did China government do?
On March 20th 2002 , the Regulations on the Administration of the Safety of Transgenic Agricultural Products (RASTAP) became effective
According to RASTAP and its measures, two methods of application are required to control the safety of transgenic products in international trade.

23. Regulations on the Administration of the Safety of Transgenic Agricultural Products (RASTAP)
First, Chinese importers or foreign exporters must apply for the transgenic products which may be imported later to be risk assessed.
Second, foreign exporters must label their transgenic products.