To assess the relationship between the distributed regularity of the glycosites in the envelope glycoproteins and the evolutionary position of various HAs and NAs, firstly, the preliminary trees for each HA and NA subtype were constructed using all available sequences; secondly ten representative sequences from discrepant clades, with consideration of host source and areas, were picked up (excluding H14, H17 and N10 due to limited records). Finally, the phylogenetic trees of HA and NA were constructed by these hundreds of sequences (File S1). The phylogenetic trees of the HA and NA were constructed by MEGA5.05 with N-J methods and a p-distance model with a bootstrap value of 1000 [41, 42] .