Figure optionsDownload full-size imageDownload as PowerPoint slide Fig. 2. Phylogenetic trees of the HA (positions 52–1032), NA (positions 730–1370), PB1 (positions 40–217
cool and PA (positions 1410–1156)
apexbio of the H1N2 influenza viruses. The method used is as given in the legend of Fig. 1. Different lineages are marked with different colors. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this paper.) Figure optionsDownload full-size imageDownload as PowerPoint slide Based on the phylogenetic trees and homology of the nucleotide sequence of gene segments of the three viruses, A/swine/Zhejiang/1/07 was directly derived from avian-like H1N1 influenza viruses and A/swine/Shanghai/1/07 and A/swine/Guangxi/13/06 were novel ressortant H1N2 influenza viruses from pigs in China containing
genes from the classical swine (HA, NP, M and NS), human (NA and PB1) and avian (PB2 and PA) lineages, which indicted that the reassortment among human, avian, and swine influenza viruses had taken place in pigs in China and resulted in the generation of new viruses.
