![]() ![]() Therefore, the final isolation of bona fide active transposable elements or verification of biological activity of reconstructed transposons must be done in a test tube. Nevertheless, there is no guarantee that any TE reconstructed from its footprints is an active element. Computational analysis also permits efficient reconstruction of ancient TEs from their incomplete or mutated copies (we consider them as genomic DNA fossils). Computer-assisted identification of DNA patterns similar to a query sequence is fast, sensitive, and cheap. However, recent explosion of the available sequence data ( 5) has brought methods of computational analysis to the forefront. All fly TEs reported in the literature or public databases before 1999 were found experimentally. The high variety of currently or recently active TEs and the role of DM as one of the basic genetic models were among the major factors behind successful studies of TEs. Both genomes contain only relatively young TEs (<20 Myr old), constituting a main component of paracentromeric regions.ĭrosophila melanogaster ( DM) is among the most important species shaping our knowledge of mobile or transposable elements (TEs) that populate eukaryotic and prokaryotic genomes and multiply by transferring their copies from one genomic place to another ( 1– 4). melanogaster are very similar to those in Arabidopsis thaliana. The chromosomal and age distributions of TEs in D. We estimated that TEs are three times more abundant than reported previously, making up ≈22% of the whole genome. We have also identified a most abundant TE in the fly genome, DNAREP1_ DM, which is an ≈10-Myr-old footprint of a Penelope-like retrotransposon. Our results indicate that Helitrons were horizontally transferred into the fly or/and mosquito genomes. ![]() We found that the “rolling-circle” Helitron transposons identified previously in plants and worms populate also insect genomes. We also show that Hoppel, a previously reported transposable element (TE), is a nonautonomous derivate of ProtoP. ![]() We found that the fly genome, which was thought to be colonized by the P element <100 years ago, harbors ≈5 million year (Myr)-old fossils of ProtoP, an ancient ancestor of the P element. These transposons populate the Drosophila melanogaster and Anopheles gambiae genomes, use a transposase that is not similar to any known proteins, and are characterized by 5-bp target site duplications. We report here a superfamily of “cut and paste” DNA transposons called Transib. ![]()
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