Table 4. Mapping 3′ ESTs to the human genome reference sequences (HG18).

	Total (%)	Poly A-	Poly A+	Bimorphic
Total mapped 3′ EST	13,467	2,984	4,898	5,585
Single mapped 3′ EST	8,178 (100)	2,113 (100)	2,760 (100)	3,305 (100)
Intergenic mapping*	2,310 (28)	808 (38)	751 (27)	751 (23)
Intragenic mapping	5,868 (72)	1,305 (62)	2,009 (73)	2,554 (77)
Distribution of Intragenic mapping
Total	5,868 (100)	1,305 (100)	2,009 (100)	2,554 (100)
Sense	5,426 (93)	1,123 (86)	1,871 (93)	2,432 (95)
intron	4,182	976	1,385	1,816
exon	1,125	125	441	558
exon/intron	127	22	45	58
Antisense	442 (8)	182 (14)	138 (7)	122 (5)
intron	385	175	113	95
exon	24	5	5	13
exon/intron	37	2	20	14

^*The mapping difference is at statistically significant level (p = 3.67×10 ⁻¹⁶, X² test).