Figure 1

Helitron secondary structure elements. Annotation of secondary structures predicted in the Hel-2 Helitrons, including formation of a 5′-inverted repeat (5′-IR), 5′- subterminal inverted repeat (5′-SIR), and a 3′-terminal stem-loop which are underscored with arrows indicating direction of inverted repeats. Helitron 5′-TC and 3′-CTAG termini are enclosed in boxes and flanking A/T dinucleotides are in small caps. dG = Gibbs Free energy.