Alternative splicing at NAGNAG acceptors results in the insertion/deletion (indel) of 3 nucleotides (nt) into the transcript. We observed non-NAGNAG splice sites with EST evidence for such a 3nt indel. Since SNPs influence alternative NAGNAG splicing, we hypothesize that these acceptors have a NAGNAG motif in another allele. The respective ESTs might be sampled from cells having such a NAGNAG allele. The goal of this project is investigate the reason for the observed tiplet indels and to use these events to predict and verify new SNPs.