FIGURE 4.

Chronograms for WO prophages. The chronogram depicted a relative divergence time of each WO prophage to the node of WOCsol–WOKgib, where we set an arbitrary scaling of relative age at 1. The estimated divergence time of each node is shown with 95% confidence intervals. Branches and labels of this unrooted tree are shown in two diverse colors to distinguish between the intact and cryptic prophages. In both of clade α and clade β, intact WOs usually appeared earlier than cryptic WOs. Clade γ was a typical clade in which all prophages were cryptic. All four WOs in clade δ were found to have genes with transcriptional activities.