Figure 2.

Examples of predicted secondary structures for each the GI-D intron subtypes proposed in this study. Base pairs shown in blue lines (or dots, for G-U pairs) were predicted by Infernal, those shown by red lines (or dots) were manually predicted. Exonic residues are shown in lower case. Colours correspond to the main base-pairings found in GI-D introns according to Zhou et al. [31] and Lehnert et al. [32]. Intron positions are numbered starting at 2; by convention of Cech et al. (S1). The secondary structures were folded by the software RNAstructure v.6.1 (S2, see Supp. References SR 1)