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Modern Biotechnology: Medical Uses of Biotechnology / Gene Therapy / Xeno-transplantation / Genetic Modification in Medicine / Cloning and Stem Cell Technology

Genetic modification is the process of altering the properties of cells in an organism by changing the genetic makeup of the DNA in the nucleus of the cell. This can include deleting or changing genes, or transferring genes from one organism to another. When an organism has had these changes made to it, it will become a genetically modified organism.

Several techniques are used to make these changes. The one most relevant to medical applications is recombinant DNA technology. Special enzymes break the gene sequence out of the DNA strand and it is transported into plasmids which are small molecules in bacterial cells. Because the plasmids have the ability to move between cells and take their DNA with them, the wanted gene can then be transferred into other cells, usually bacterial cells, and the bacterial cells are now genetically modified.

The first use of genetically modified organisms in medicine was to use the bacteria as factories for the introduced genes. By fermentation techniques the bacteria could be multiplied many times over and the multiplication of the introduced genes would also multiply the protein or hormone that the gene would normally produce. This is the technique that allowed the mass production of products like recombinant human insulin for treatment of diabetics.

Other medical uses of this technology have been to genetically modify animals so that they express certain enzymes or proteins in their milk. This has been done to obtain medicine for human use, from rabbits, cows and other animals. When this occurs the animal becomes a genetically modified organism, but the medicine that is obtained, while the product of a genetic modification process, is not itself a GMO. It is a recombinant product but retains the characteristics of the original enzyme or protein.

The next step in the chain of possible applications of GMO technology is where a particular gene is used as a medicine in a person who has a disease or disability. This is gene therapy. The introduced gene will express the enzyme or protein that is absent or deficient, and in this way the person will be treated. As a result of this application of gene therapy, the person will, technically, be a genetically modified organism, as the introduced gene will have altered their genetic properties, but only in relation to the disease or disability they have.

The Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) provides a clear and short summary on genetic modification including a useful diagram and useful links to further information.