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Eléments transposables et évolution des génomes Volume 1, issue 2, Mars - Avril 1997

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Authors
Institut de recherche sur la biologie de l'insecte, UPRESA CNRS 6035, Université François-Rabelais, Faculté des Sciences, avenue Monge, 37200 Tours

Transposable elements are middle and highly repetitive components of prokaryote and eukaryote genomes. They are able to transpose from one locus to another. The different classes of transposable elements are determined according to their mode of transposition. Class I elements, which correspond to retrotransposons, Lines and Sines, need a RNA intermediate to transpose. They are then characterized by the synthesis of the reverse transcriptase. Class II elements are mobile in a DNA form and produce the transposase which catalyse all the steps of transposition. These elements correspond to bacterial and eukaryote transposons. The mobility of transposable elements produces genome variability. This variability induces some changes in gene organization and functions. Under selection pressure, some of these mutations will remain in the genome. Transposable elements have therefore an important impact on genome evolution. In biotechnology, properties of transposable elements are also used to create transformation vectors both in animals and plants.