PerspectiveGenetics

MITEs—The Ultimate Parasites

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Science  11 Sep 2009:
Vol. 325, Issue 5946, pp. 1352-1353
DOI: 10.1126/science.1179556

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Summary

Transposable elements (TEs) are fragments of DNA that can jump from one genome position to another, often producing extra copies of themselves in the process. Sequences generated by TEs are the most abundant component of practically all eukaryotic genomes. For instance, about 90% of human DNA is made up of TEs. They are potent sources of mutation: In Drosophila, TEs are responsible for 50 to 80% of the visible spontaneous mutations (those that result in a visible phenotypic change) (1) and can generate a wide spectrum of mutations, from subtle regulatory changes to gross genomic rearrangements. On page 1391 of this issue, Yang et al. (2) show how a special type of TEs, called miniature inverted repeat transposable elements or MITEs, transpose and accumulate in the genome.