1. Transgenic Organisms

2. Transgenic or Genetically Modified Organism
Annie – genetically engineered to have resistance to the infection mastitus
Transgenic Plants – engineered for resistance to something or for enhanced production.

3. What are GM Foods?
GM foods are crop plants created for human or animal consumption using recombinant techniques
These plants or animals were modified in the lab to enhance desired traits such as increased resistance to herbicides or improved nutritional content.
These improvements can be accomplished through selective breeding, but that takes a lot longer and results are not always as expected.

4. Overview of GMO techniques
DNA from different organisms is essentially the same (is universal).
First step in transferring DNA is to "cut" or remove a gene segment from a chain of DNA using enzyme "scissors" to cut at a specific site (restriction enzymes).
These enzyme cut the plasmid. Next, researchers place
the desired gene segment into the plasmid.
Because the cut ends of both plasmid & gene are
chemically "sticky," they attach through complementary base pairing, forming a plasmid containing a new gene.
To complete, researchers DNA Ligase
to paste the new gene in place.

5. Why Bacteria or Viruses as Vectors?
Ease of handling.
Bacteria & bacteriophages grow in simple liquid media
Short generation time, Large numbers, Molecular mechanisms are universal, Genetic analysis is rapid & easy

6. Examples of GM plants
For example, plant geneticists can isolate a gene responsible for drought tolerance and insert that gene into a different plant. The new genetically-modified plant will gain drought tolerance as well.
Genes from non-plant organisms also can be used. The best known example of this is the use of Bt genes in corn and other crops.
Bt or Bacillus thuringiensis, is a naturally occurring bacterium that produces crystal proteins that are lethal to insect larvae. Bt. crystal protein genes have been transferred into corn, enabling the corn to produce its own pesticides against insects such as the European corn borer
But….

7. Another example……
Several varieties of tomatoes have been engineered to ripen more slowly, making them last longer in shipment and on consumers' shelves.
Favr-Savr tomatoes.

8. Advantages of GM (plants)
Pest resistance Crops treated with pesticides can cause health hazards, run-off of agricultural wastes from pesticides & fertilizers can poison the water supply, disrupting food chains (bioaccumulation).
GM foods such as Bt. corn can help eliminate the application of chemical pesticides and reduce the cost of food.
Herbicide tolerance. Weeds reduce production. If a crop is genetically-engineered to be resistant to a very powerful herbicide, less would be needed & production could be increased while preventing environmental damage.
Disease resistance Plant biologists are working to create plants with genetically-engineered resistance to diseases.
Heat or Cold tolerance An antifreeze gene from cold water fish has been introduced into plants such as tobacco and potato. With a antifreeze gene, these plants are able to tolerate cold temperatures that normally would kill.
Cont.

9. More Advantages of GM/P
Drought tolerance/salinity tolerance- Plants that can withstand long periods of drought or high salt content in soil and groundwater will help people to grow crops in marginal agriculture land.
Nutrition If rice could be genetically engineered to contain additional vitamins and minerals, nutrient deficiencies could be alleviated.( For example, blindness due to vitamin A deficiency is a common problem in third world countries. Researchers at the Swiss Federal Institute of Technology Institute for Plant Sciences have created a strain of "golden" rice containing an unusually high content of beta-carotene (vitamin A)).
Pharmaceuticals. Researchers are working to develop edible vaccines in tomatoes and potatoes. These vaccines will be much easier to ship, store and administer than traditional injectable vaccines.
Phytoremediation Plants such as poplar trees have been genetically engineered to clean up heavy metal pollution from contaminated soil. Some bacteria have been altered to digest oil from oil spills.

10. Advantages Of Transgenic Animals
Fewer animals for each medical experiment because we get more accurate results.
Can use simple animals like fruit flies and earthworms, or rats and mice instead of using complex animals like monkeys.
We don't need to take blood from animals to test for proteins because we can get them to produce those proteins in their milk.
Health
Increase nutritional value of food: GE can be used to modify existing food to give them new characteristics.
Products
Increased Productivity GE has the potential to produce plants or animals that produce more of the product we need. Animals may produce more milk or leaner meat

11. How Can GM or transgenic animals help?
Help us to understand the workings of genes, & allow us to study diseases..
In some cases anew gene may lead to an animal developing a human disease being studied. In other cases researchers can delete individual genes from animals (giving clues to what that gene does.)
For years humans have selectively bred animals to get woollier sheep, bigger cows and faster horses etc. Transgenic animals have altered traits resulting from changes made to their genetic material. Since DNA is universal, it can be transferred between unrelated organisms. This can produce other animals with characteristics that might not otherwise be available.

12. An example of a GMA GM Somatotropin for Milking Cows
Somatotropin is a genetically engineered pharmaceutical developed by a company called Monsanto. When provided to milking cows, the cow's milk production increases.
What are the advantages? Less cost per liter.
What are the disadvantages? Animal rights groups have protested that increased milk production is causing pain to the udders of animals & incidence of increased mastitis.

13. Disadvantages of GMP
Environmental
Unintended harm to other organisms (disruption of natural food chains) - a study has shown that pollen from B.t. corn caused high mortality rates in Monarch caterpillars.
(read the aritcle on the handouts page)
Reduced effectiveness of pesticides Many people are concerned that insects, through natural gene transfer, will become resistant to pesticides.
Gene transfer to non-target species Another concern is that crop plants engineered for herbicide tolerance and weeds will cross-breed, resulting in the transfer of the herbicide resistance genes from the crops into the weeds. These "superweeds" would then be herbicide tolerant as well.
Cont.

14. Human health
Allergenicity There is a possibility that introducing a gene into a plant may create a new allergen or cause an allergic reaction in susceptible individuals
Unknown effects on human health There is a growing concern that introducing foreign genes into food plants may have an unexpected and negative impact on human health.
Economic Concerns
Bringing a GM food to market is lengthy and costly. Ag-biotech companies need profitable return. Many new plant genetic engineering technologies & GM plants have been patented. Consumer advocates worry that patenting these new varieties will raise seed price so high that small farmers & third world farmers will not be able to afford them, thus widening the gap between the wealthy and the poor.
Terminator genes in some seeds – more money for the big seed companies (not related to GMO’s, really)

15. More Disadvantages of GMA
Health
Unknown long-term effects: GE products are so that their long term effects are unknown.
Allergens and Toxins: GE products could produce new toxic substances or allergens.
New viruses and bacteria: Genes could transfer from one species to another. These genes could create new viruses and bacteria with properties that present drugs cannot deal with.
Superbugs: Genes could possibly transfer from one species to another. If an antibiotic resistant gene were to transfer from an organism into a disease-creating bacteria such as Streptococcus then an antibiotic-resistant bug would be created.
Enviromental
Biochemical instability: In a living organism, genes do not always work on a "one gene, one trait" basis. Genes interact with each other and also with their immediate environment. The introduction of new genetic material may create unforeseen interactions with other genes that may produce toxins or allergens.

16. Social and Cultural
Cultural values When transgenic species are formed, genes are transferred from one species to another. Various beliefs hold that species are separate entities and have their own spirits. Mixing of these spirits is unacceptable. Certain religions prohibit the eating of certain types of meat.
Playing “God” syndrome: Various beliefs (religious, cultural, social) believe that species are separate entities and have their own spirits. They also believe that humans should not interfere with the "nature". By creating or modifying plants and animals scientists are "playing god".

17. How to make a GMO Construction of a transgene
- The promotor region of a gene needs to be cut along with the gene and the termination chain so that only that gene is expressed in the new organism, and no more.
Inserting the transgene
Microinjection
Collected eggs are fertilized.
Eggs must be identified before mitosis occurs.
A microtube (photo) is used to hold the fertilised egg in place & an extremely fine needle is used to inject a tiny amount of solution, containing many copies of the transgene into the male pronucleus

18. Embryonic stem cell transfer
It’s possible using appropriate vectors to carry out specific genetic modifications; such as removing or substituting a specific gene. The embryonic stem cells can be injected into the blastocyst stage of the embryo - the resulting fetus will be chimera (organism having mixed genes of different species)
Retroviral vectors
Retro viruses can be used to carry the gene sequence of interest into embryonic cells. The gene is still inserted randomly into the genome. Because the sequence locates at different places in the genome in different embryos the resulting offspring are not always the same, so further selective breeding is needed to obtain clear lines with the desired traits.

19. Breeding
Only a small percentage of the offspring are transgenic. These are the first generation or founder animals. They are then mated with non-transgenic animals to produce a second generation of offspring that are heterozygous for the gene.
The second generation heterozygous offspring are then mated with each other to produce a percentage of offspring who are homozygous for the desired gene. Resulting homozygous third generation offspring will then have a stable form of the gene available whenever they mate with other homozygous offspring.

20. Bibliography
Text
Why we use GMA
Making a GMA
Advantages of GMA
Disadvantages of GMA
Example of GM Somatotropin for Milking Cows