Table 4. A list of amino acid positions containing the same residue in avian and recent ancestral swine viruses, yet changed to a different one in pandemic (H1N1) 2009 and human viruses*.
| Gene | Position | Avian virus residue | Recent swine viruses residue† | Pandemic (H1N1) 2009 virus residue | Human virus residue |
|---|---|---|---|---|---|
| PB2 |
684 |
A(3,278), T(70), S(11), V(9), G(6), D(1),
E(1) |
A(18) |
S(61) |
S(1,944), A(806), G(2), P(2),
Y(1) |
| PB1 |
216 |
S(3,299), G(62), N(37), C(11),
I(7) |
G(9), S(7)‡ |
G(80) |
G(1,708), S(1,039), N(5), I(4),
D(1) |
| PA | 204 | R(2,202), K(674), E(1), G(1), S(1) | R(17) | K(61) | K(1,776), R(991) |
| 356 | K(3,309), R(34), N(7), E(1), I(1) | K(16), R(1) | R(61) | R(2,705), K(30) |
*Boldface indicates dominant amino acid residue type. PB, polymerase B; PA, polymerase A. †Same 18 recent ancestral swine viruses used in Table 3. ‡PB1-216 is dominated by residue G (G[8), S[1]) when considering only a subset of 9 PB1 sequences that are phylogenetically closer to pandemic (H1N1) 2009 virus. This statistic clearly shows the amino acid residue transition from avian to human signature within the population of recent swine viruses.