Preliminary decision tree to classify 77 authentic and 14 cryptic dystrophin exons. Exons are passed down the tree beginning at the top, where a "yes" result on any test means that it should be passed down to the left. The features tested in this tree are the maximum entropy at the 3' splice site (ss) (ME3'ss), the SF2/ASF density (SF2/ASF-D), the GC content at the 5'ss (GC5'ss), the maximum entropy at the 5'ss (ME5'ss), the free energy at the 5'ss U1 snRNP binding site (FE), the number of exonic splicing silencer (FESS), and the Shapiro score at the 3'ss (SH3'ss). The internal nodes of the tree represent index values that are tested for each exon as it is passed through the tree. Each successive node in the tree represents a decision that is based on those values, until a final classification is reached (the leaves). Authentic and cryptic exons were classified into four groups each.