Figure 2. Length and Boundary Nucleotides of Introns Are Important Properties for Detecting a Splice Junction.

(A) Fewer than 10% of introns in RefGene annotation were greater than 10,000 bp in length. PWMs for splice junctions with respect to true donors (B) and true acceptors (C) were applied to true splice junctions defined by RefGene annotations and to randomly selected genome sequences containing the canonical dinucleotide pair at the appropriate position. The scores, which were computed based on the profile model, for donors and acceptors were plotted and showed that true splice junctions acquired high scores. The information content and the relative frequency of nucleotides at each position are measured in bits (vertical axis of the sequence logo diagrams) to indicate the strength of signals. Two bits of information are required to determine the content of a DNA sequence.

AU, arbitrary units.