Fig. 1.

(A) Helitron structure: 5′ TC and 3′ CTRR termini (shown in uppercase), a predicted small hairpin structure near the 3′ end, and insertion into the target dinucleotide AT (shown in lowercase). (B) The end sequences of 8 Helitrons (gray rectangle) from A. thaliana. 5′ start with TC, 3′ end with CTRR, insert between AT dinucluetide (red rectangles), and flanking sequences are shown. Sequences within the insertion site align very well and sequences outside of the insertion cannot be aligned because they are insertions at different genomic locations.