This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Techniques in molecular biology, Subject name: Biochemistry
Which is not a method of gene therapy: 
Select and explain. 
A. FISH, B. Transfection, C. Electroporation, D. Bacteriophage
A: FISH
Answer: A: FISH 
Explanation: FISH (Fluoresecent In Situ Hybridization) is used for diagnosis, Not for gene therapy or treatment. Gene therapy When a gene or DNA is introduced into a cell for the treatment of a disease. Methods of Gene therapy Transformation Transfection Transduction Electroporation Uptake and incorporation of naked DNA into bacteria from the external environment Transfer of non-viral genetic material into eukaryotic cells Uptake of chimeric DNA takes place Introduction of genetic material using viruses (bacteriophage). An electric field is applied which increases cell membrane permeability, allowing DNA, drugs or chemicals to be introduced into the cell