. Author manuscript; available in PMC: 2010 Aug 1.

Published in final edited form as: Virology. 2009 Jun 5;390(2):289–297. doi: 10.1016/j.virol.2009.05.002

TABLE 1.

Rates of nucleotide substitution and selection pressures in the North American influenza gene pool

Gene	Substitution rate (10⁻³ subs/site/year)		Mean d_N/d_S [95% CI]

	Mean	95% HPD
H4	2.5	2.0–3.1	0.092 [0.077, 0.108]
H6	4.2	3.3–5.0	0.146 [0.132, 0.161]
H6 lineage A	4.4	3.5–5.5	0.125 [0.132, 0.146]
H6 lineage B	4.1	2.9–5.6	0.211 [0.183, 0.240]
H6 lineage B1	4.6	2.8–6.6	0.284 [0.179, 0.423]
H6 lineage B2	2.0	1.6–2.4	0.262 [0.205, 0.329]