Gene Transfer

Gene transfer is the technique of taking a gene out of one organism and placing it in another organism.


4.4.8. Outline a basic technique for gene transfer involving plasmids, a host, restriction enzymes and DNA ligase.

Cutting and pasting DNA
Restriction enzymes called endonucleases are used to cut out the gene that needs to be transferred. If both the beginning and end of a gene are cut, the gene is released and can be removed from the donor organism.

DNA ligase is used for pasting genes as it recognizes the parts of the sticky ends and attaches them together.

DNA Cloning
A host cell is needed in addition to those two enzymes. Although yeast cells can be used as host cels, E. coli is most popular.  Plasmids are small circular DNA molecules found in bacteria, and can be cut with the same restriction enzyme. This leaves the sticky ends in the plasmid, which are, effectively, unattached hydrogen bonds. The plasmid can be cut at particular sites called the restriction sites. To copy a gene, it has to be glued into a plasmid.

The gene is pasted into the plasmid using DNA ligase. The plasmid is now called a recombinant DBA and it can be used as a vector.

The vector is placed inside the host bacterium and the bacterium is given ideal conditions to grow. This is done by putting it into a bioreactor. This process has been used to make human insulin.

4.4.10. Discuss the potential benefits and possible harmful effects of one example of genetic modification.

Benefits of GMO:

1. Increase yields in regions of food shortage
2. Yields crop with specific dietary requirement such as vitamins and minerals
3. Crops that don't spoil easily
4. Farmers can be in control of what crops or livestock they produce.
5. Multinational companies who make GM plants claim they will enable farmers in developing nations to reduce hunger by using pest-resistant crops or GM plants which require less water.

Harmful effects

1. No one knows the long term effects of GMOs in the wild. Genes from GM plants could be integrated into wild species giving them an unnatural advantage over other species and an ability to take over the habitat.
2. Bt-crops which produce toxins to kill insects could be harmful to humans.
3. Risks for allergies: could be allergic to GM tomatoes.
4. Critics are worried that large portions of the human food supply will be the property of a small number of corporations.
5. High-tech solutios are not necessarily better than simpler solutions. Crop production could be increased by teaching farmers how to use water and natural pest-control systems more efficiently.
6. A proliferation of genetically modified organisms may lead to a decrease in biodiversity.