Phylogenetic comparison based on nucleotide sequence of PB1 gene with that of vaccine strains and the strains from different countries. Our strain is marked as ‘●’. The tree was rooted with cognate stretch of strain B/Victoria/504/2000 for PB1. The tree was created by using neighbor-joining method with 1000 bootstrap replicates.
Mukherjee et al. Virology Journal 2012 9:233 doi:10.1186/1743-422X-9-233