FIGURE 3.

Distribution of alternative 3′-splice sites relative to the dominant splice site. (A) The frequency of alternative 3′-splice-site activation is shown in nucleotide resolution. The X-axis indicates the nucleotide distance between alternative and dominant splice sites. The Y-axis indicates the number of alternative splice sites. The dashed line indicates that the Y-scale is split. (B) The plot represents the probability that a YAG is activated as an alternative splice site. Each point was calculated by dividing the number of alternative splice-site usage events at a particular distance from the dominant splice site by the total number of times YAG occurs at that same distance from splice sites within the human genome (∼125,000 exons). YAG occurs in >95% of alternative and constitutive splice sites. The Y-axis is shown in log scale.