Figure 7

Signatures of swine-isolated influenza A PB2 proteins against the H2H characteristic variant pattern. The H2H characteristic variant pattern is the same as that used in Figure 6. The symbol 'X' at a characteristic site indicates that the residue is unknown, due to an incompletely sequenced protein. Some patterns, whose signatures are represented by other retained sequences, were removed from the alignment to make the figure more compact. The GenPept accession numbers for all sequences used are listed in Table S2 in Additional file 1.