Table 1. ORF data for influenza A viruses.

Gene	Length of transcripts(aa)	Sequence countsanalyzed	Total ORF counts(F1, F2, F3)	Initiation sites peramino acid (×10−2)
PB2	759	19,320	70 (37, 26, 7)	9.2
PB1	757	19,378	81 (38, 33, 10)	10.7
PA	716	20,404	77 (26, 35, 16)	10.8
NP	498	20,219	58 (26, 28, 4)	11.6
M1	252	28,216	24 (14, 8, 2)	9.5
M2	97	24,218	8 (2, 3, 3)	8.2
M42	99	18,349	8 (2, 3, 3)	8.1
NS1	230	23,125	28 (17, 7, 4)	12.2
NS2	121	21,536	15 (10, 2, 3)	12.4
NS3	194	512	16 (11, 4, 1)	8.2
H1	566	11,238	62 (9, 38, 15)	11.0
H2	562	468	76 (17, 44, 15)	13.5
H3	566	8025	69 (11, 46, 12)	12.2
H4	564	909	50 (6, 32, 12)	8.9
H5	568	1501	55 (17, 30, 8)	9.7
H6	566	1085	71 (16, 42, 13)	12.5
H7	560	750	67 (19, 36, 12)	12.0
H8	566	92	60 (14, 36, 10)	10.6
H9	560	1180	66 (16, 37, 13)	11.8
H10	561	509	57 (17, 27, 13)	10.2
H11	565	382	59 (8, 36, 15)	10.4
H12	564	124	60 (12, 34, 14)	10.6
H13	566	38	68 (12, 44, 12)	12.0
H14	568	11	42 (7, 29, 6)	7.4
H15	570	10	48 (14, 24, 10)	8.4
H16	565	31	65 (12, 38, 15)	11.5
H17	564	3	40 (11, 24, 5)	7.1
H18	561	1	39 (8, 23, 8)	7.0
N1	469	9918	55 (13, 25, 17)	11.7
N2	469	9651	52 (10, 27, 15)	11.1
N3	469	699	55 (9, 33, 13)	11.7
N4	470	188	60 (11, 30, 19)	12.8
N5	473	167	48 (10, 24, 14)	10.1
N6	470	1182	57 (15, 23, 19)	12.1
N7	470	471	44 (9, 22, 13)	9.4
N8	470	1362	61 (10, 31, 20)	13.0
N9	470	421	53 (7, 25, 21)	11.3
N10	442	3	28 (9, 12, 7)	6.3
N11	447	1	28 (6, 16, 6)	6.3

An ORF is defined as containing a start codon AUG at a given genomic position, with ≥5% prevalence from all analyzed sequences from the NCBI.