Analysis of known positive and negative splice sites using the Purpuratus and Vertebrate splice site models. Histograms of the scores given to known positive (solid lines) and negative (dashed lines) splice sites were generated (bin size = 2) for the Purpuratus (A) and Vertebrate (B) splice site models by analyzing the genes used to generate the models (Additional file 2, 3, and 4; ). For example, 22% of the known positive sites received scores between 4 and 6. The average of the means (Table 3) is shown by a vertical dotted line. The gray region corresponds to N0.95, and P0.05 (Table 3), which flank the left and right side of the gray region, respectively, and are shown as dashed/dotted lines. The ✳ located on the 0.25% line indicate the mean of the positive and negative scores.