Fig. 3.

Cumulative probability distributions (CPDs) for the frequency of splice variant numbers in the reference category (biological process; 7201 genes), apoptosis (477 genes) and cell–cell signaling (440 genes). The CPD was taken in the ‘reverse’ direction, from high to low number of splice variants, to illustrate more effectively the enrichment in high numbers of splice variants for apoptosis. The CPD for apoptosis was significantly different from the reference category (K-S, P < 0.0001, computed for the normal direction for the CPD), whereas that for cell–cell signaling was not (K-S, P = 0.92). The expanded inset emphasizes the dramatic enrichment for apoptosis in the high-splice variant-number tail of the distribution, in contrast to the behavior of the control category, cell–cell signaling.