Slip-strand mispairing is a slow method of gene expression control, normally through modifying the regulatory region of a gene. Disruption within the reading frame can lead to premature termination codons, and overlapping promoter or regulatory region modification can change the activity of the gene promoter.
Increasing or decreasing the copy number of a repetitive tract in the bacterial DNA occurs during slip-strand mispairing, and is caused by the DNA polymerase dissociating from the template DNA during replication to give 2 copies of varying length.
As slip-strand mispairing is a change to the DNA sequence, it is inherited by bacterial progeny. Epigenetic control of gene expression is (generally) not inherited by subsequent generations.