Skewed phylogenetic distribution of sequences in the Aligned Sequence Database. Shown are the number of sequences in the ASD for each lineage and the percentage of the total number of sequences. Editing information is available for several genes from the underrepresented groups, but they were not included in the ASD because only portions of the genes were analyzed. The dotted lines indicate lack of RNA editing based on previous predictive and experimental analyses (see main text). The marchantiid liverworts are thought to have secondarily lost the ability to perform RNA editing. The relationship between plant lineages was taken from Knoop .