[GHS Biotechnology]


Genetically Modified Organisms

Genetically modified organisms are organisms with artificially altered DNA. They can be created by:

a. Adding a foreign gene.

b. Altering the base sequence of an existing gene.

c. Deleting or "Turning off" and existing gene.

Adding a Foreign Gene:

Organisms that are altered in this way are known as transgenic organisms.

A new foreign gene is added from a different species. The new foreign gene thus produces the protein it is responsible for, either creating a product we desire, or modifying the transgenic organisms so they can better survive.

Examples of uses of transgenic organisms:

1. Incorporating bacterial genes for resistance to herbicides so a crop plant is not killled by weed killer (herbicide).

*2. Incorporating bacterial genes which produce their own insecticide into corn plants. Herbivorous insects are thus prevented from eating such plants.

3. Some bacteria thrive on toxic waste. The genes allowing breakdown of the toxic substance can be added to other more numerous bacteria and then applied to toxic spills for cleanup (bioremediation).

4. Sheep have been modified to carry the gene for alpha-1-antitrypsin. This protein is produced in the sheep's milk, which is then give to humans to treat hereditary emphysema!

5. The gene for insulin production has been aded to yeast. These recombinant yeast thus produce large quantities of insulin for use by diabetic humans.

Altering an Existing Gene:

Existing genes in the organism are altered to make it produce at higher levels (such as growth hormone which makes the organism larger). Or gene complexes in tissues where these complexes usually don't work are switched on to make the desired protein (the basis of gene therapy).

Deleting/ "Turning Off" an Existing Gene:

Existing genes may be deleted or deactivated to prevent the expression of their trait (so they don't produce their protein). *An example involves deactivating the gene responsible for the ripening of tomatoes. This new gene can then be inserted into tomato DNA to give them a longer shelf life.

 

[Ethics of Genetically Modified Organism Technology]

[Restriction Enzymes] [Gene Cloning]


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