Figure 1. Comparative secondary structure models for the group IE intron at position 989 in the nuclear SSU rRNA gene of Hildenbrandia rubra (BC2). The 5 and 3 splice junctions are marked with arrows. G:C and A:U base pairs are connected with short lines; G:U base pairs with ; other non-canonical (non-Watson Crick) base pairs with a . The P2.1 domain is shaded (see Fig. 2 ).
Figure 2. Gallery revealing similarities and differences in the P2.1 domains (shaded in Fig. 1) in secondary structure models of three group IE introns. Each helical region is labeled; only the 5 half of P13 is shown.
- Metarhizium anisopliae var. anisopliae LSU 2066 (Fungi);
- Cryptendoxyla hypophloia SSU 989 (Fungi);
- Exophiala nigra SSU 989 (Fungi);
- Hildenbrandia rubra SSU 989 (red algae);
- alignment of the P2.1 domain of eight representative group IE introns. Helices are boxed and connected by lines; only the 5 half of P13 is shown. Parentheses enclose hairpin loops. Species names are abbreviated, and the intron positions in the rRNA genes are shown in parentheses. Crypt.hypo., Cryptendoxyla hypophloia; Cryph.paras., Cryphonectria parasitica; Gaeum.gram., Gaeumannomyces graminis var. tritici; Exo.nigra., Exophiala nigra; Hild.rubra., Hildenbrandia rubra; Metar.anis., Metarhizium anisopliae var. anisopliae; Scyta.dimi., Scytalidium dimidiatum; Skele.pseu., Skeletonema pseudocostatum; Tille.flav., Tilletiopsis flava.
Figure 3. Neighbor-joining tree constructed using corrected distances (HKY-85 model) of IE and IC1 introns inserted in the nuclear rRNA genes of different eukaryotes. Numbers above branches represent distance bootstrap values (1000 replicates) using the HKY-85 model (first number), distance bootstrap values using the GTR+I+G model (second number) or bootstrap values using maximum parsimony (third number). Branches with an asterisk or lacking a value had less than 50% support in that analysis. The insertion sites in the LSU or SSU rRNA genes are indicated to the right of the taxa.
Figure 4. Neighbor-joining tree constructed using corrected distances (HKY-85 model) of the nuclear SSU rRNA gene sequences from different eukaryotes. Numbers above branches represent distance bootstrap values (1000 replicates) using the HKY-85 model (first number), distance bootstrap values using the GTR+I+G model (second number) or bootstrap values using maximum parsimony (third number). Branches with an asterisk or lacking a value had less than 50% support in that analysis.
