Abstract
Transduction is the bacteriophage-mediated transfer of host DNA between bacterial cells. Together with transformation and conjugation, this is one of the major mechanisms of horizontal gene transfer (HGT), promoting genetic diversity in bacteria. For a bacteriophage to transduce bacterial DNA, imprecision during phage DNA packaging or during prophage excision are required. This occurs in the natural environments where phages are abundant and diverse, and is considered to be an important driver in bacterial evolution. Studies of model phage–host systems have revealed mechanisms of transduction and have led to the development of sophisticated genetic methods. In this article, the mechanisms of transduction, its power and use as a genetic tool, and its occurrence and effects in the environment are summarized.