Fig. 1

The diversity of reverse transcriptases and DDE transposases found in mobile genetic elements. Groups having representatives with solved 3-D structure are underlined. a Phylogenetic analysis of known RTase types (after [88]). In addition to TEs, host genes (TERT, RVT) and non-mobile bacterial RTs are included into the analysis. Also shown are the types of endonucleases/phosphotransferases associated with each RT type. b Dendrogram representation of 19 DDE TPase eukaryotic superfamilies from Repbase (www.girinst.org) and 21 prokaryotic DDE families from ISfinder (www-is.biotoul.fr) databases [29, 133] as of this writing. Left, prokaryotic; right, eukaryotic; middle, with cross-domain representation. The dendrogram is star-like, except for cross-domain families with prokaryotic and eukaryotic branches [71, 74, 75]. Bacterial families are in blue/green; eukaryotic in orange/red/purple. Dotted lines denote clades A, B, C from [76]; smaller clades are not shown; assignment of many TEs to known families could not be performed due to the dearth of known representatives. MuA from phage Mu was assigned to clade A, although it is not represented in ISfinder. The more distantly related RuvC-like DEDD TPases of the RNase H family are not included; neither are the mechanistically different HUH, S, Y, or HEN families