Comparison of the inverted repeat sequences of insertion elements IS14751, IS1207, IS31831, IS13869, ISPsp2, IS1096, ISBli1, and ISBli3. Nucleotides that were identical in at least 9 of 16 sequences are enclosed in boxes. IR-L and IR-R indicate the inverted repeats at the 5′ end upstream and the 3′ end downstream of the tnpA gene, respectively. The length of each inverted repeat sequence and the identity ratio (number of identical nucleotides/length of inverted repeat) for IR-L and IR-R of each insertion element are indicated on the right.