Intron length distribution of 10 plants
According to Roy's method, many predicted introns in the plant genomes had in-frame stop codons, and the predicted introns in these genomes were equally as likely to be a multiple of 3 bp (3n) as to contain a plus one (3n + 1) or two (3n + 2) bp. Here was an example of three phases from an Arabidopsis thaliana gene, AT1G17600.1 (Fig. 2).
By analyzing genome sequence annotations, we got three-phase intron distributions for 10 plant species (Table 6). If the plant intron annotation is more accurate, the number of three phases should be similar (one-third each). For 80% (8/10) of species, there were similar numbers of the three phases. It should be noted that most of these plant species annotations were the best annotations to date, but new annotations will be continually released to correct errors and false-positive results.