The New Dictionary of Cultural Literacy, Third Edition. 2002.
gene therapy
A promising technology that involves replacing a defective gene in the body with a healthy one. This can be done by removing cells from the body, using genetic engineering techniques to change defective sequences in the DNA, and then reinserting the cells. This technique has been carried out successfully, for example, on bone marrow cells, in which defective cells were successfully replaced with healthy, genetically engineered cells. Scientists hope to find an agent, such as a therapeutic virus, that will be able to correct defective DNA in situ. (Seecloning vector.)