Complete sequence of a mariner transposable element from the predatory mite Metaseiulus occidentalis isolated by an inverse PCR approach

Degenerate primers designed and synthesized based on two conserved regions of the mariner transposase open reading frame were used to amplify a 454 bp DNA fragment from M. occidentalis. Two inverse primers were then synthesized and used to amplify flanking genomic DNA fragments from M. occidentalis by a ligation-mediated inverse PCR. The complete mariner element (Moc 1) was 1284 bp long, including the imperfect 28 bp inverted terminal repeat sequences, and shared 59% similarity to an active 1286 bp long D. mauritiana mariner element (Mos 1). Insertions, deletions and substitutions were observed in the Moc 1 sequence at several positions. No intact open reading frame was detected and the Moc 1 element is considered inactive. Stringent Southern blot hybridizations revealed at least twelve copies of mariner sequences similar to Moc 1 in the colonies tested.