Which horizontal gene transfer mechanism uses bacteriophages to transfer DNA between bacteria?

• A. Conjugation
• B. Transformation
• C. Transduction
• D. Binary Fission

Answer: (C)

Transduction is the mechanism by which bacteriophages transfer DNA from one bacterium to another. During phage infection, a phage can accidentally package fragments of the host’s DNA into its capsid. When that phage particle goes on to infect another bacterium, it injects that DNA, which can then recombine with the recipient’s genome. This can happen in two forms: generalized transduction, where random bacterial genes are carried, and specialized transduction, where genes near the prophage integration site are transferred.

This is distinct from other forms of horizontal gene transfer. Conjugation requires direct cell-to-cell contact and transfer of DNA via a conjugative pilus, usually involving a plasmid. Transformation involves uptake of free DNA from the environment by competent cells. Binary fission is just cell division, not a method for transferring DNA between different cells.