Evolution of pogo , a separate superfamily of IS630-Tc1-mariner transposons, revealing recurrent domestication events in vertebrates

and , as two superfamilies of - ( ) group, have been well-defined. However, the molecular evolution and domestication of transposons, once designated as an important family of the superfamily, are still poorly understood. Here, phylogenetic analysis show that transposases, together with , DD34E/ , and transposases form four distinct monophyletic clades with high bootstrap supports (> = 74%), suggesting that they are separate superfamilies of group. The superfamily represents high diversity with six distinct families ( , , , , , and ) and wide distribution with an expansion spanning across all the kingdoms of eukaryotes. It shows widespread occurrences in animals and fungi, but restricted taxonomic distribution in land plants. It has invaded almost all lineages of animals-even mammals-and has been domesticated repeatedly in vertebrates, with 12 genes, including centromere-associated protein B (CENPB), CENPB DNA-binding domain containing 1 (CENPBD1), Jrk helix-turn-helix protein (JRK), JRK like (JRKL), transposable element derived with KRAB domain (POGK), and with ZNF domain (POGZ), and transposable element-derived 2 to 7 (TIGD2-7), deduced as originating from this superfamily. Two of them (JRKL and TIGD2) seem to have been co-domesticated, and the others represent independent domestication events. Four genes (TIGD3, TIGD4, TIGD5, and POGZ) tend to represent ancient domestications in vertebrates, while the others only emerge in mammals and seem to be domesticated recently. Significant structural variations including target site duplication (TSD) types and the DDE triad signatures (DD29-56D) were observed for transposons. Most domesticated genes are derived from the complete transposase genes; but CENPB, POGK, and POGZ are chimeric genes fused with additional functional domains. This is the first report to systematically reveal the evolutionary profiles of the transposons, suggesting that and are two separate superfamilies of group, and demonstrating the repeated domestications of in vertebrates. These data indicate that transposons have played important roles in shaping the genome and gene evolution of fungi and animals. This study expands our understanding of the diversity of transposons and updates the classification of group.