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Helena structure in Drosophila species. Structure of the reference copies of Helena-like elements. DNA sequences: AAA, poly-A tail. Protein sequences: gag, nucleocapsid-like domain; RTase, reverse transcriptase; *: position of start codons; #: position of stop codons. D. simulans and D. melanogaster structures are from Rebollo et al. [18]. The sequences are in Additional file 1.
