FIG. 1.

Phylogenetic analysis of the Matrix 2 (M2) genes of influenza virus isolates from South Korea. Phylogenetic neighbor-joining trees comparing the nucleotide sequences of the M genes of the 207 avian and human isolates in South Korea in this study with nucleotide sequences from other selected human and avian influenza virus strains. The scale represents the number of substitutions per nucleotide. Viruses in boldface type indicate Korean LPM and BPF isolates bearing the amantadine resistance phenotype. Branch labels record the stability of the branches over 1,000 bootstrap replicates. Only bootstrap values of ≥60% are shown in the tree due to limited space and the reliability of groupings above 60%. Standard nomenclature is used for human isolates. Dk, duck; Ck, chicken.