(a) Hierarchical clustering and heat-map analysis of differential splice junctions in tumour samples. The colours of squares below the tree denote the subtype of each sample. Below the array tree and the subtype identification row, the heat map of the 1,469 splice junctions is shown. The complete list of up- and downregulated splice junctions can be found in Supplementary Data 1. (b) Venn diagram of differential splice junctions in SF3B1MUT compared with SF3B1WT tumours. Numbers show the count of alterations within only 5′ss (186 events) or only 3′ss (1,124 events). The overlapping area represents junctions that are either ambiguously attributed to an alternative donor or acceptor site, or attributed to both alternative 3′ and 5′ splice sites (159 events). (c) Distances between the alternative and canonical SF3B1MUT-sensitive 3′ss. For alternative 3′ss within the 50 nts preceding the canonical 3′ss (765), the distance between the alternative (AG’) and corresponding canonical (AG) 3′ss was plotted as a histogram. Negative distances mean the alternative AG’ upstream of the canonical AG, whereas positive distances mean the AG’ downstream. The 0 point demarks the position of the canonical AG.