A type of transposon found in the DNA of various organisms, including yeast, Drosophila, and mammals, that multiplies by forming copies of itself using a mechanism similar to that of retroviruses. It undergoes transcription to RNA, then creates a DNA copy of the transcript with the aid of the enzyme reverse transcriptase. This DNA copy can then reintegrate into the cell’s genome, leaving the original version in situ. Retrotransposons, like retroviruses, can cause cancer in vertebrates by inserting in the genome near growth-promoting genes, causing the latter to be abnormally expressed. Retrotransposons account for a large proportion of the moderately repetitive DNA found in eukaryote genomes, the most abundant being the LINEs and SINEs.