Final decision tree to classify 77 authentic and 15 cryptic dystrophin exons. The structure of the tree is as described for Figure 1. The features tested in this tree include seven indexes used in the preliminary tree (Figure 1) and one additional index, exon size (SIZE). This tree classified the authentic dystrophin exons into five groups (groups A to E), containing 30, 1, 42, 2, and 2 exons, respectively. The cryptic exons were classified into four groups (groups a to d).