TABLE 2

Mean rates of substitution for all segments and coding regions of A(H3N2) viruses circulating between 1968 and 2011

SegmentRegionMean rate of substitution (10−3 substitutions/site/yr)
NucleotideaAmino acidb
Mean95% HPD
LowerUpper
PB2Full2.412.172.671.4
PB1Full2.542.312.780.8
PB1-N402.542.302.780.8
PB1-F23.672.814.589.5
PAFull2.282.052.521.8
PA-N1552.392.122.681.1
PA-N1822.412.122.711.2
PA-X1.580.982.201.6
HAHA03.993.634.3810.8
HA14.844.325.3814.9
HA23.122.633.641.4
NPFull2.512.212.822.9
NAFull3.272.933.639.1
MFull2.071.752.40
M11.881.552.220.9
M22.631.943.331.4
NSFull2.492.132.85
NS12.482.102.882.2
NEP2.321.792.860.5
  • a The mean rate of nucleotide substitution per site per year was estimated using BEAST.

  • b Genetic distance to A/Hong Kong/1/1968 was calculated from the phylogenetic tree and was plotted as a function of time. The mean rate of amino acid substitution per site per year was inferred from the linear slope (Fig. 4).