Cotranscriptional splicing efficiency differs dramatically between Drosophila and mouse

Intron definition and exon definition in mouse and fly: correlations of 3′SS ratios with intron and 5′-exon lengths. (A) Intron length does not correlate with 3′SS ratio in mouse (green) but does in fly (blue) (***, P < 0.001, Kurstal-Wallis Test, all pairwise). (B) The 3′SS ratio in mouse (green) is lowest when the length of the 5′ exon is 50–500 bp. In fly (blue), the length of the 5′ exon is negatively correlated with the 3′SS ratio of a given intron (***, P < 0.001, Krustal-Wallis Test, all pairwise). Box plots span the 95th–fifth percentiles.