Figure 1
From: Swine influenza viruses isolated in 1983, 2002 and 2009 in Sweden exemplify different lineages
Evolutionary relationships of the HA genes of A/swine/Skåne/1321/1983(H1N1), A/swine/Lidköping/1193/02 (H1N1) and A/swine/Sweden/1021/09 (H1N2). The phylogenetic tree was generated by the neighbor-joining method. Bootstrap values of 1000 resamplings in per cent are indicated at key nodes. Bootstrap values above 50% are shown. The Swedish viruses are highlighted with bold letters and the lineages are indicated according to the Influenza A Virus Genotype Tool [15].