Transduction: Host DNA Transfer by Bacteriophages

Bacteriophage-mediated transfer of DNA from an infected cell to a recipient bacterium is called transduction and is one of the three major mechanisms of horizontal gene transfer (HGT), alongside transformation and conjugation, that promote genetic diversity in bacteria. Transduction arises from errors in DNA packaging or prophage excision and can occur in the natural environment where phage are abundant and genetically and morphologically diverse. Transduction is considered an important driver in bacterial adaptive evolution. In contrast to fully functional phage, gene transfer agents (GTAs) might be prophage remnants that are now host-adapted ‘constitutive transducers’ enabling the exchange of DNA between some bacteria. In this article, the mechanisms of transduction, its power as a genetic tool, and its occurrence in the environment are summarized.