Structures of the recombinants R19, R24, and R27 derived from a cell line carrying the 1.6-kb AAVS1 episome. The recombinants most likely arose from an 1.6-kb AAVS1 episome that had recombined with a Line-1 element prior to AAV infection. R19, R24, and the rearranged AAV-negative episome were isolated from the same cell line and the same experiment. R27 was retrieved from the same cell line as well, but at a later passage. ▮▮▮▮▮▮, AAV sequences (boxed numbers); ▪, AAVS1 sequences (underlined numbers); ——, vector backbone sequences (plain numbers); ······, unknown sequences; □, ITR, AAV terminal repeats; ∧∧∧∧∧∧, recombinant junctions; , duplicated vector sequence (nt 5871 to 5977); , duplicated AAVS1 sequence (nt 480 to 539); ?, unknown position of the Line-1 sequence within the unrelated sequence of R19 and the rearranged EBV episome.