Reverse transcriptase is an enzyme that produces DNA from RNA. It is used by retroviruses to generate a DNA copy of their RNA genome when infecting a host cell. Molecular biologists use reverse transcriptase to produce cDNA from mRNA, which can then be used to transfer genes to other organisms. Gene therapy aims to treat genetic diseases by altering the genotype, either inserting a functional gene to replace a recessive disease allele, or preventing expression of a dominant disease allele. Viral vectors, particularly retroviruses modified to not replicate, are often used to deliver the therapeutic gene to target cells. One example is treatment of Severe Combined Immunodeficiency through insertion of the ADA gene into a patient's stem cells using a retro

2. They use the enzyme, Reverse Transcriptase for production of DNA from RNA

3. Reverse Transcriptase is used after the Retrovirus has entered the host cell used to make a DNA copy of their RNA genes.

5. Single-stranded DNA copies of the mRNA are made using reverse transcriptase called cDNA.

6. DNA polymerase is used to convert the single-stranded DNA into double stranded DNA produces genes that can be transferred into another organism.

8. IF disease caused by a recessive allele… fully functional dominant allele inserted into defective cells.

10. Body cells altered do not develop into gametes.

11. Often large numbers of cells will be altered.

12. Genetic disease may be cured in treated individual

13. Can pass to offspring

14. Germ-line therapy:

15. Sperm or egg cells treated (or cells that will divide to produce sperm or egg cells)

16. Disease will not pass onto offspring