Transposon nucleic acids comprising a transposon end sequence and a calibration sequence for DNA sequencing in the transposon end sequence. In one embodiment, the transposon end sequence is a Mu transposon end. A method for the generation of DNA fragmentation library based on a transposition reaction in the presence of a transposon end with the calibration sequence providing facilitated downstream handling of the produced DNA fragments, e.g., in the generation of sequencing templates.