Fig. 1From: Amino acid sites related to the PB2 subunits of IDV affect polymerase activityPhylogenetic tree of Influenza viruses based on PB2 sequences. Red branches on the phylogenies represent influenza A viruses, green branches represent influenza B viruses, blue branches represent influenza C viruses, and purple branches represent influenza D viruses. The black circle represents the strains in this studyBack to article page