Molecular Biology and Evolution 19:2101-2109 (2002)
© 2002 Society for Molecular Biology and Evolution
maT—A Clade of Transposons Intermediate Between mariner and Tc1
,2
*Research School of Biological Sciences, The Australian National University, Canberra;
CSIRO Entomology, Canberra;
Department of Botany and Zoology, The Australian National University, Canberra
A group of transposons, named maT, with characteristics intermediate between mariner and Tc1 transposons, is described. Two defective genomic copies of MdmaT from the housefly Musca domestica, with 85% identity, were found flanking and imbedded in the Md
E7 esterase gene involved in organophosphate insecticide resistance. Two cDNA clones, with 99% identity to each other and 72%–89% identity to the genomic copies were also obtained, but both represented truncated versions of the putative open reading frame. A third incomplete genomic copy of MdmaT was also identified upstream of the putative M. domestica period gene. The MdmaT sequences showed high identity to the transposable element Bmmar1 from the silkworm moth, Bombyx mori, and to previously unidentified sequences in the genome of Caenorhabditis elegans. A total of 16 copies of full-length maT sequences were identified in the C. elegans genome, representing three variants of the transposon, with 34%–100% identity amongst them. Twelve of the copies, named CemaT1, were virtually identical, with eight of them encoding a putative full length, intact transposase. Secondary structure predictions and phylogenetic analyses confirm that maT elements belong to the mariner-Tc1 superfamily of transposons, but their intermediate sequence and predicted structural characteristics suggest that they belong to a unique clade, distinct from either mariner-like or Tc1-like elements.