Figure 3.

Sequence alignment of the I. engelmannii maturase protein sequence in intron atp9i87g2 and its homolog from M. polymorpha. The Isoetes cDNA-derived protein sequence results from RNA editing of 81 DNA-encoded codons as shown below the alignment. Background shading colours indicate C-to-U (cyan), U-to-C (magenta) and silent edits (green). Codon changes increasing sequence similarity with Marchantia are underlined and are mostly located within conserved maturase domains 0–7 and ‘X’ (56) as indicated. The atp9i87 maturase is translated in frame with the small upstream exon(s) of atp9 across the splice donor site (arrowhead). Upstream intron atp9i21g2 (vertical line) is present in Isoetes, but not in Marchantia.