Fig. 1.

Maximum likelihood phylogenetic tree based on the polyprotein amino acid sequences of Ty1/Copia elements. Only bootstrap values greater than 50% (red dots) or greater than 70% (black dot) are indicated. The tree has been rooted by the BEL element from D. melanogaster. The names of the species are abbreviated as follows: DAn, D. ananassae; DBi, D. biarmipes; DBp, D. bipectina; DEl, D. elegans; DEu, D. eugracilis; DFi, D. ficusphila; DGri, D. grimshawi; DKi, D. kikkawai; DMel, D. melanogaster (in red); DMoj/Dmoj; D. mojavensis; DPer/DP, D. persimilis; Dpse, D. pseudoobscura; DSe, D. sechellia (in green); DSi, D. simulans (in blue); DTa, D. takahashi; DVir, D. virilis; DWil, D. willistoni; Dya/DY, D. yakuba (in pink). Four sequences from other organisms are included. Yellow stars represent cases of confirmed horizontal transfers (see details in Additional file 3: Figure S1a)