Alignment of the rps1i25g2 and rpl2i846g2 sequences highlighting regions important for secondary structure folding. The six domains of the introns are indicated. Nucleotides shaded in black (65%) are identical, similar nucleotides explained by transitions (A/G and C/U) are shaded in gray (13%). Intron internal interaction sites (Greek letters) are marked with blue boxes, exon/intron binding sites with red boxes, and the branching adenosine with a green box. The corresponding intron binding sites in the 5′ exons are shown on top. Two indels in the EBS1 loop of rps1i25g2 versus rpl2i846g2 may have targeted the new intron to the rps1 gene as discussed in the text. The shaded sequence alignment was created with GeneDoc (http://genedoc.software.informer.com/2.7/).
