retrotransposon

Retrotransposons are a unique class of transposons, often called "jumping genes," that can move to different locations within a genome. Unlike other transposons that use a "cut and paste" method, retrotransposons employ a "copy and paste" mechanism. This process begins with the transposable DNA being transcribed into RNA. This RNA then moves to a new location in the genome, where it is converted back into DNA by an enzyme called reverse transcriptase before insertion. This "copy and paste" method leads to the proliferation of repetitive DNA sequences throughout the genome, making up significant portions of many eukaryotic genomes, including about 20 percent of the human genome in the form of LINEs (long interspersed nuclear elements).1