Practice question

DNA transposons move without RNA stage; transposase binds terminal inverted repeats, assembles paired-end complex, introduces staggered double-strand cuts at donor site releasing element with 3'-OH ends that attack target DNA phosphodiester backbone. Host repair polymerases fill single-stranded gaps generating target site duplications characteristic of insertion. Information transfer remains as DNA throughout, distinguishing cut-and-paste transposition from retrotransposition. Copy number usually preserved unless donor gap repaired from sister chromatid yielding increase, balancing genome stability. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.