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Gene therapy. Gene therapy Using gene technology to treat genetic disorders Usually involves adding a functional copy of a gene to cells which only contain a dysfunctional copy. The dysfunctional gene is not removed, which means that this technique works best with recessive disorders (why?)
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Gene therapy • Using gene technology to treat genetic disorders • Usually involves adding a functional copy of a gene to cells which only contain a dysfunctional copy. • The dysfunctional gene is not removed, which means that this technique works best with recessive disorders (why?) • Two types, somatic cell and germ line cell gene therapy
Somatic cell gene therapy. • Somatic cells are differentiated cells, in which some genes are transcribed and some are not. • Gene therapy by augmentation – adding new, functional copies of a dysfunctional gene to the cells that express that gene. • Eg – the correct copy of the gene that causes cystic fibrosis can be added to cells in the lining of the lungs using a liposome or a virus vector.
SCID • Severe, Combined Immunodeficiency • A condition which leads to complete dysfunction of the immune system • Various forms, one of which is caused by a recessive mutation in the gene for the enzyme Adenosine Deaminase (ADA), which leads to the build up of toxins which kill T lymphocytes.
Somatic cell gene therapy in cancer treatment. • Gene therapy can be used to introduce new genes into tumour cells.
Germ line cell gene therapy • This involves introducing a new gene into a sperm cell, an ovum, a zygote or a very early embryonic cell. • This means that the new gene will be seen in all the body cells of individual that develops from that germ line cell. • That individual will also be able to pass on the modification to the next generation • This is illegal in humans pretty much everywhere….
Comparison of germ line cell and somatic cell gene therapy germ line cell Somatic cell
Comparison of germ line cell and somatic cell gene therapy germ line cell Somatic cell
Xenotransplantation Transplantation of cells tissues and organs between animals of different species Why would this be potentially useful? Why is it problematic? How could genetic engineering make xenotransplatation a more realistic option?
Potential Benefits and Risks of Genetic Engineering • Micro-organisms • Animals • Plants • Humans