Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Evolutionary relationships of the HA gene of A/swine/Sweden/1021/09 (H1N2) compared to genetically related influenza viruses. The phylogenetic tree was generated by the neighbor-joining method. Bootstrap values of 1000 resamplings in per cent are indicated at key nodes. The Swedish virus is highlighted with bold letters and the representative isolates referred to in Table 1 are underlined.
