Transposable elements are relatively long DNA sequences in prokaryotic and eukaryotic genomes that act as mobile genetic elements. These elements, which represent a large part of the genomes of many species transpose by a mechanism that involves DNA synthesis followed by random integration at a new target site in the genome.

All transposable elements encode for transposase, the special enzyme activity that helps in the insertion of transposons at a new site, and most of them contain inverted repeats at their ends. The major difference between bacterial transposable elements and their eukaryotic counterparts is the mechanism of transposition. Only eukaryotic genomes contain a special type of transposable elements, called retroposons, which use reverse transcriptase to transpose through an RNA intermediate.

Transposition may result in splicing of DNA fragments into or out of the genome. During replicative transposition, the transposon is first replicated...