Table 2.

An estimation of the relative expression of human exons involved in non-linear splicing by their representation in dbEST

Expression category	Non-linear single exon (n = 24)	Non-linear 5′ multi-exon (n = 152)	Non-linear 3′ multi-exon (n = 151)
High	17 (70.8%)	50 (32.9%)	46 (30.5%)
Medium	4 (16.7%)	64 (42.1%)	63 (41.7%)
Low	3 (12.5%)	38 (25%)	42 (27.8%)

The expression category HIGH includes exons (56 591 exons) which are represented by ≥34 ESTs in dbEST, with MEDIUM exons (53 837 exons) being represented by ≥9 and ≤33 ESTs and low exons (58 014 exons) being represented by ≥1 and ≤8 ESTs in dbEST. Non-linear single exons are those exons that are involved in non-linear single exon splicing (dark grey genome information space in Figure 1). Non-linear 5′ multi-exons are those exons that are the 5′ exon in a non-linear multi exon splicing event (light grey genome information space in Figure 1). Non-linear 3′ multi-exons are those exons that are the 3′ exon in a non-linear multi exon splicing event (light grey genome information space in Figure 1).