(A) Distribution of five Mariner families ( Mariner_Tbel , Mariner1_BT , TIGGER1 , Mariner-28_SIn , and Mariner-N1_CPe ) in placental mammals, marsupials, and insects. The phylogeny is adopted from published trees of insects and mammals[12–15]. Marsupials are represented by three species (Monodelphis domestica, Macropus eugenii, Sarcophilus harrisii). The scale bar on the bottom left indicates time of evolutionary branching in the tree. Species with genomic sequences available from public databases are highlighted in orange. (B) Phylogenetic position of the two horizontally transferred Mariners (Mariner_Tbel and Mariner1_BT: red color), relative to other closely related Mariners. Most of the families are from insects with color-coded branches: ants (green), bees (orange), flies (pink) and other insects (blue). The remaining branches (black) are from mammals and planarian (SMAR7). Except for a few individual sequence segments (with accession numbers), all other families are represented by consensus sequences deposited in Repbase (except for highly similar copies). (C) Structural relationship between Mariner1_BT and Mariner-N1_CPe family. The species abbreviations are: ACe (Atta cephalotes), AEc (Acromyrmex echinatior), AFl (Apis florea), AMe (Apis mellifera), BTe (Bombus terrestris), BT (Bos taurus), CA (Chymomyza amoena), CFl (Camponotus floridanus), Del (Drosophila elegans), DEr (Drosophila erecta), DF (Drosophila ficusphila), EEu (Erinaceus europaeus), HSal (Harpegnathos saltator), LHu (Linepithema humile), MRo (Megachile rotundata), PBa (Pogonomyrmex barbatus), SIn (Solenopsis invicta), SMAR7 (Schmidtea mediterranea), Tbel (Tupaia belangeri), CPe (Carollia perspicillata).