Novel Class II DNA Transposon in Selaginella moellendorffii

Transposons are auto catalytic DNA sequences capable of moving in a genome. Currently identify and studying transposons using sequencing technologies has led to uncovering a diversity of Transposons and their impact on genomes. In analyzing the Selaginella moellendorffii genome, a new Class II DNA transposon has been discovered. The transposon, consists of a 6bp Target Site Duplication (TCTTCA/TCGTCA,GAAAAA/GAAAAA,GAAATC/GAAATC), ~100-150bp Tandem Inverted Repeat, and a single open reading frame encoding a transposase. Analysis of the transposase identified the catalytic domain DDE, and shows similarity to other transposons in animals. Genome analysis identified 72 copies, of which several are predicted to have a functional transposase. Low DDE similarity to Ginger DDE was found using Blast, E-value=0.018. Further characterization of the element shows lack of insertion preference near genes, p>0.001, which contrast to the small ~100Mb genome size of Selaginella moellendorffii. Using the transposase to search for similar elements uncovered multiple hits in fungi, fish, coral and anemone. This elements also currently appears restricted to the Selaginella genus in plants. This study shows the diversity and unique characteristics of a novel DNA element identified in Selaginella moellendorffii.