FIG 2.

A hypothetical evolutionary pathway of the polioviruses isolated in Biysk in 2010. The names of the isolates' genomes are given in gray rectangles. The nucleotide changes of their genomes are shown in frames, with the arrows directed from and to these frames indicating acquisition and loss of the relevant mutations, respectively. (The exact timing of these changes is unknown.) The mutations resulting in amino acid substitutions are underlined, and those that apparently appeared independently in different strains are highlighted in boldface and italics. The substitution C₄₆₅₃U (marked with *) was present in a portion of PT1 molecules. Dashed lines connecting isolated PT3 virus with PT4-0/PT4 virus reflect the uncertainty of their real interrelationship. The timeline on the left of the figure shows the number of days after the isolation of the first strain (genome PT1).