Table 5.

Rates of change in different sublineages of H9N2 and H5N1 influenza viruses from Hong Kong

GeneNucleotide range analyzedNucleotide change/siteaAmino acid change/siteeRate of amino acid change/nucleotide changef (mean ± SE)P valueg
Qa/HK/G1/97-likeb (group I)Dk/HK/Y280/97-likec (group II)H5N1dQa/HK/G1/97-like (group I)Dk/HK/Y280/97-like (group II)H5N1Qa/HK/G1/97-like (group I)Dk/HK/Y280/97-like (group II)H5N1I:III:H5II:H5
PB2988–22890.01170.01480.00810.00460.00050.00690.39 ± 0.010.05 ± 0.110.74 ± 0.42<0.05* NS<0.05*
PB167–14280.00810.02160.01280.00000.00130.00220.000.057 ± 0.080.19 ± 0.08NS<0.05* <0.05
PA19–16770.01290.01700.00970.00430.00650.00360.34 ± 0.070.42 ± 0.290.39 ± 0.09NSNSNS
HA88–10770.01260.01480.0180.00661.43 ± 0.070.48 ± 0.14<0.05*
NP34–13980.00850.01740.00660.00350.00220.00440.41 ± 0.210.14 ± 0.120.64 ± 0.37<0.05NS<0.05
NA20–14210.00820.0120.00680.00550.83 ± 0.100.46 ± 0.14<0.05*
M150–9820.01030.00730.00710.00160.00080.00160.12 ± 0.270.15 ± 0.340.24 ± 0.54NSNS<0.05
NS141–8790.00060.0230.01370.00090.01610.01410.59 ± 1.320.68 ± 0.171.02 ± 0.04NSNS<0.05*
  • a Rate of nucleotide change at each nucleotide site compared to the reference strain (number of nucleotide changes/length of sequence analyzed).

  • b Reference virus is Qa/HK/G1/97; compared to the first second set of five viruses in Table 3 which were isolated in 1999.

  • c Reference virus is Dk/HK/Y280/97; compared to the five boldfaced viruses in Table 3 which were isolated in 1999.

  • d Reference virus is Ck/HK/258/97; compared to Dk/HK/Y283/97, Dk/HK/P46/97, Goose/HK/W355/97, Ck/HK/786/97, and Ck/HK/915/97.

  • e Rate of amino acid change for each amino acid site compared to the reference strain (number of amino acid changes/length of amino acid sequence analyzed).

  • f Calculated as amino acid change per site/nucleotide change per site.

  • g Calculated for comparing the rates of amino acid change per nucleotide change between different groups: I:II (group I compared to group II), I:H5 (group I compared to H5N1 group); II:H5 (group II compared to H5N1 group). If P value is <0.05, there is significant difference between the two groups, unadjusted for multiple tests; if P value is <0.05*, the difference is still significant even adjusted for multiple pairwise testing by Bonferroni adjustment. If P value is >0.05, there is no significant (NS) difference between the two groups compared.