Table 3.

The mean 3-1 dinucleotide occurrence of the U/C-ended synonymous codons.^a

Segment	Host	*pA		*pC		*pG		*pU
		CpA	UpA	CpC	UpC	CpG	UpG	CpU	UpU
PB2	Avian	4.17	1.56	2.84	2.22	1.39	4.42	1.63	1.8
PB2	Human H2N2	3.98	1.85	2.26	2.89	0.78	4.9	1.26	2.07
PB2	Pandemic H1	4.69	1.22	2.98	2.18	1.11	4.66	1.51	1.83
PB2	Seasonal H1	3.97	1.77	2.39	2.57	0.49	5.51	1.83	1.7
PB2	Seasonal H3	4.64	1.51	2.5	2.55	1.17	4.32	0.74	2.59
PB1	Avian	6.61	2.36	2.51	2.81	1.64	6.16	2.66	1.71
PB1	Human H2N2	6.57	2.5	2.2	2.99	1.76	6.06	2.98	1.36
PB1	Pandemic H1	6.54	2.8	2.26	2.92	1.03	6.63	2.4	2.31
PB1	Seasonal H1	6.46	2.98	2.58	2.3	0.85	7.02	2.47	2.68
PB1	Seasonal H3	6.41	2.84	2.63	2.4	1.56	5.95	2.52	2.21
PA	Avian	6.19	1.54	2.35	1.98	1.53	6.1	3.27	2.44
PA	Human H2N2	6.19	2.16	1.57	2.35	1.49	6.54	2.83	3.16
PA	Pandemic H1	6.01	1.59	3.09	1.58	1.12	6.87	3	2.5
PA	Seasonal H1	6.14	1.97	1.48	2.49	1.02	6.57	2.73	3.57
PA	Seasonal H3	6.78	1.91	1.99	1.69	1.69	5.91	2.01	4.08
HA	Avian H1	4.65	1.49	2.58	2.37	1.58	6.54	2.38	2.46
HA	Avian H3	6.06	1.33	2.83	2.42	1.47	6.6	2.1	1.43
HA	Human H2N2	4.45	2.23	1.88	2.37	1.58	6.45	1.53	1.8
HA	Pandemic H1	5	2.21	2.53	2.41	1.43	6.02	2.02	2.32
HA	Seasonal H1	4.68	1.98	2.28	2.57	1.24	6.79	2.34	1.8
HA	Seasonal H3	6.4	1.49	3.33	1.91	1.56	6.37	1.3	1.84
NP	Avian	2.96	0.77	2.01	1.65	1.37	3.88	1.66	1
NP	Human H2N2	3.84	0.78	1.03	2.12	1.4	3.96	1.31	1.19
NP	Pandemic H1	2.49	1.39	2.08	1.25	0.83	4.61	1.67	1.06
NP	Seasonal H1	3.74	0.54	1.33	1.83	1.16	4.35	1.37	1.19
NP	Seasonal H3	3.37	0.98	1.61	1.66	1.39	3.93	0.92	1.79
NA	Avian N1	4.22	2.07	0.6	2.15	0.88	4.6	1.65	2.16
NA	Avian N2	4.16	3.04	0.74	1.53	0.86	4.95	1.41	2.79
NA	Human H2N2	4.35	2.87	0.61	1.9	1.37	4.59	1.23	3.02
NA	Pandemic H1	5.15	1.68	0.54	2.55	0.81	4.84	2.46	1.51
NA	Seasonal H1	5.33	1.86	0.74	2	1.06	4.28	1.46	2.71
NA	Seasonal H3	4.4	2.27	0.72	2.34	1.1	4.84	1.43	2.03
M	Avian	1.75	0.26	0.61	0.76	0.33	1.98	0.16	0.36
M	Human H2N2	1.43	0.74	0.17	0.97	0.18	2.14	0.18	0.32
M	Pandemic H1	1.82	0.31	0.67	0.8	0.17	2.07	0	0.5
M	Seasonal H1	1.12	0.92	0.18	1.14	0.24	2.09	0.16	0.34
M	Seasonal H3	1.51	0.66	0.28	0.89	0.05	2.28	0.1	0.4
NS	Avian	1.41	0.71	0.77	0.69	0.28	1.77	0.57	0.34
NS	Human H2N2	1.42	0.72	1	0.6	0.19	1.54	0.34	0.56
NS	Pandemic H1	1.7	0.73	0.71	0.56	0.33	1.67	0.74	0.17
NS	Seasonal H1	1.47	0.62	0.95	0.9	0.17	1.81	0.37	0.48
NS	Seasonal H3	1.69	0.65	0.74	0.82	0.17	1.59	0.34	0.5

^aThe dinucleotide pairs with significant difference were shown in bold (P < 0.05 in Mann−Whitney U test and, difference of mean values >1).