A previous report described the discovery of a group I, self-splicing intron in the DNA polymerase gene of the Bacillus subtilis bacteriophage SPO1 (1). In this study, the DNA polymerase genes of three close relatives of SPO1: SP82, 2C and phi e, were also found to be interrupted by an intron. All of these introns have group I secondary structures that are extremely similar to one another in pr...