Transduction is the transfer of DNA by what agent?

• A. transfer of DNA between living bacteria that are in physical contact (F-plasmid)
• B. transfer of DNA from bacteriophage
• C. uptake of naked DNA
• D. replication of plasmid within a cell

Answer: (B)

Transduction is DNA transfer mediated by a bacteriophage. In this process, a phage infects a donor bacterium and accidentally packages fragments of that bacterium’s chromosomal DNA into its capsid. When the phage goes on to infect a recipient bacterium, it injects that donor DNA, which can then recombine with the recipient’s chromosome. This mechanism relies on a virus acting as the vehicle to move genetic material between bacteria, unlike other methods that require direct contact between cells or uptake of naked DNA. There are two main forms: generalized transduction, where any gene can be transferred, and specialized transduction, where genes near the phage integration site are transferred. Replication of a plasmid within a cell does not involve transferring DNA to another cell, and transformation involves uptake of naked DNA from the environment, not phage-mediated transfer.