The intron database was generated from our cDNA alignments. Each of the approximately
70,000 cDNA alignments was examined for relatively large gaps (at least twelve nucleotides) in the genomic side
of the alignment with no corresponding gap in the cDNA side of the alignment. In addition at least five bases
on either side of the genomic gap had to match perfectly, and at least seven more bases on either had to match
almost perfectly. If these conditions were all met the genomic gap was considered an intron and put in the database,
which currently holds 24826 distinct introns. The average intron is supported by 2.4 cDNA or EST sequences, though
14120 of the introns are only supported by a single cDNA or EST.