Fig 7. Signs of positive selection for the H5N1-CNS virus are detected in the nasal turbinate and brainstem tissue of infected ferrets at 6 dpi.

Positive selection was calculated using the πN/πS ratio. Values above 1 denote positive selection (A). Variant analysis suggests independent evolutionary events shown by unique variants in brainstem tissue from ferrets F10 and F12 (B). The types of mutation are represented by shapes: synonymous (Syn.) as circles, nonsynonymous (Nonsyn.) as tringles and variants in the untranslated regions (UTR) as diamonds. The segments are shown as concatenated in the x-axis. Dashed grey line shows consensus cut off at 0.5 of frequency whereas dashed black line marks 1 of frequency.