
(AC)m-(GT)n introns predate the divergence of tetrapods from teleosts. The measurement of frequency distribution of AC and GT repeat hexamers around 5′ ss and 3′ ss was expanded to 24 genomes (listed in dendrogram). The degree and shape of AC and GT enrichment is illustrated in the cartoon. The percentage of (AC)m-(GT)n intron in the genome is indicated in brackets, and the number of genomes analyzed in the category is in parentheses.











