Figure 4.

Lateral transduction. Lateral transducing phages start replicating while still integrated in the host chromosome. In situ replication creates multiple integrated phage genomes. Some of these genome copies later get excised and follow the typical cycle forming infectious particles. In those that stay integrated, the terminase complex initiates in situ packaging from the pac site near the middle of the phage genome and proceeds to package towards the host genome. The first virion contains a chimeric DNA molecule that is half phage and half bacterial. The terminase continues through the adjacent host chromosome efficiently packaging up to seven headfuls before the frequencies decrease. In situ packaging and the typical excision–replication–packaging cycle happen in parallel, producing both the transducing particles and the actual infectious virions. (Created with BioRender.com.)