Figure 5

Comparison of antigenic site residues with residues under positive selection. (a) Comparison of H1 antigenic site residues described in this study (Table 2, color-coded as for Figure 1a) with residues positively selected in human H1N1 viruses [18] colored lime green. (b) Comparison of H3 antigenic site residues described in this study (Table 2, color-coded as for Figure 1a except that the H1C epitope defined in this study is shown in red) with residues predictive of novel lineages in human H3N2 viruses [33] colored lime green. To orient the reader, the receptor binding site (RBS) has been labeled in purple. (c) Comparison of H3 antigenic site residues described in this study (Table 2, color-coded as for Figure 1a) with directionally selected residues in human H3N2 viruses [34] colored lime green. Structure files showing epitopes, viewable using PyMol, are available on line (Additional files 17 and 18).