FIG. 2.

Reduced median network for panel of EHV-1 isolates. Polymorphism data were derived from a set of ORFs containing at least one nonsynonymous substitution and from ORF68 sequences in a panel of 25 isolates representing neuropathogenic and nonneuropathogenic outbreaks and all six ORF68 groupings. Isolates are labeled as shown in Table 6, and the area of each circle is in proportion to the frequency of isolates sharing the same genotype. The positions of substitutions at ORF30 nt 2254 are shown (30.1’), and other substitutions are to scale but unlabeled. The parallelogram at top left indicates the alternative mutational paths involving two variable sites. Groupings based on ORF68 are indicated by dashed lines.