FIGURE 3.

Splicing regulation and function. (A) The distribution of the Pearson correlation coefficients based on the PSI of age-dependent retained introns and the expression level of the respective genes (solid lines) or randomly selected genes (dashed lines). The legend shows P-values of the Wilcoxon test comparing the observed and control distributions. (B) The proportions of the last (top) and the second-to-last (bottom) non-age-dependent introns or age-dependent introns in one of the species among all retained introns. The error bars show 95% confidence intervals. Only genes with at least five introns were included. (C) The relationship between PSI variation between species and splicing propensity differences at the alternative donor sites. (D) The proportions of splicing differences between species that could be explained by the sequence differences within the core splicing sites at a different PSI change amplitudes. (E,F) The distributions of PSI values at the alternative donor sites within the PARP2 and ULK3 genes. Reference and alternative alleles (red) are shown under the consensus donor site sequence. In the ULK3 sequence, SNP overlaps both ancestral and alternative donor sites. (G) The distributions of the average primate phastCons scores for protein-coding cassette exons and adjacent introns.