Evidence for an inactive transposable mariner-like element in Anopheles albimanus

Transposable elements may eventually be used as transformation Vectors of a nti-Plasmodium genes in natural populations of Anopheles mosquitoes. The ma riner transposable element is widespread in most animal phyla and we wished to test for its presence in the important Latin American malaria vector, A nogheles albimanus. Degenerate primers were designed from the consensus of insect mariner elements and used in a polymerase chain reaction to amplify a fragment of the predicted size from An. albimanus. The fragment was clone d, sequenced, and determined to be a mariner-like element through multiple alignment with known insect mariner elements. Dot blot and Southern blot an alyses showed only one or a few elements per haploid genome. The cloned fra gment was used as a probe to isolate similar sequences from an An. albimanu s genomic DNA library. A 659-base-pair done was 57% similar at the DNA leve l with mariner elements from Anopheles gambiae, Chrysoperla ptorapunda, and Haematobia irritans. This low sequence similarity is comparable to that fo und among mariner-like elements in all insects. However, conserved amino ac id motifs were not discovered nor was a single open reading frame found. Th ese aspects suggest that the An. albimanus,mariner-like element may represe nt an ancient transposition event but that the element is no longer active, the typical open reading frame having been disrupted through nucleotide in sertions and deletions.