Table 4.

Site-specific frequencies and position weight matrix (PWM) for 301 3′ ss. The consensus sequence (UUUUUUUUAYAG ∣GCUUC) can be obtained from those large site-specific PWM entries, with the most important sites in bold italics . The χ ² test is performed for each site against the expected background frequencies. The sites are labeled with first-exon site as 1. The PWM is nearly identical when the introns in 5′ UTR were excluded.

Site	A	C	G	U	χ 2	P	A	C	G	U
−12	70	58	37	136	51.729	0.0000001	−0.4898	0.0122	−0.7264	0.7114
−11	79	51	23	148	79.511	0.0000001	−0.3161	−0.1727	−1.4074	0.8332
−10	86	45	14	156	105.131	0.0000001	−0.1941	−0.3525	−2.1155	0.9090
−9	43	33	23	202	236.063	0.0000001	−1.1886	−0.7978	−1.4074	1.2812
−8	56	43	31	171	130.216	0.0000001	−0.8100	−0.4178	−0.9801	1.0412
−7	102	35	31	133	54.256	0.0000001	0.0512	−0.7134	−0.9801	0.6793
−6	103	46	38	114	23.130	0.0000380	0.0653	−0.3210	−0.6881	0.4574
−5	100	36	25	140	68.925	0.0000000	0.0228	−0.6729	−1.2882	0.7532
−4	145	27	41	88	45.473	0.0000001	0.5574	−1.0854	−0.5790	0.0850
−3	15	127	0	159	284.824	0.0000002	−2.6877	1.1404	−8.2350	0.9364
−2	299	1	1	0	605.789	0.0000003	1.5998	−5.5977	−5.6756	−8.2346
−1	0	0	301	0	1171.443	0.0000004	−8.2345	−8.2351	2.2908	−8.2346
1	109	39	74	79	9.936	0.0191208	0.1467	−0.5580	0.2697	−0.0701
2	84	66	55	96	6.036	0.1098600	−0.2279	0.1981	−0.1571	0.2102
3	103	58	50	90	2.969	0.3964877	0.0653	0.0122	−0.2940	0.1173
4	96	45	56	104	8.655	0.0342400	−0.0359	−0.3525	−0.1312	0.3253
5	100	69	39	93	11.698	0.0084938	0.0228	0.2620	−0.6508	0.1645