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.
Phylogenetic tree of influenza A NS1 genes. The tree is a NJ tree using p distance. Nine groups are indicated: groups 1, 3, 6, 7, and 9 are avian, groups 2 and 8 are equine, group 4 is human, and group 5 is swine. A/Brevig Mission/1/18 (arrow) is near the root of group 5. Bootstrap values are given for selected nodes, and a distance bar is shown under the tree.
