An Active Non-LTR Retrotransposon With Tandem Structure in the Compact Genome of the Pufferfish Tetraodon nigroviridis

Genomic structure of Zebulon elements in T. nigroviridis. The position of 5′ truncations is shown by broken arrows. Most of them are from single sequences and could therefore not be assigned either to the upstream or to the downstream copy; they were arbitrarily positioned in the downstream copy. Trace sequences (http://www.ncbi.nlm.nih.gov/blast/tracemb.html) reflecting the genomic site before insertion are shown, and their percentage of nucleotide identity with the site sequences directly flanking Zebulon insertions is given. Horizontal arrows show the direction of gene transcription. Putative flanking target site duplications are shown. (RT) Reverse transcriptase; (CCCHC) putative CXCX₃CX₈HX₅C zinc finger-like domain.