FIG 6.

Final egg-passaged viruses have few shared consensus- and subconsensus-level variants. For each of the five viruses, three different lists of mutations were identified as follows: all mutations identified, mutations occurring at a frequency above 50%, and mutations occurring at a frequency below 50%. Each series of lists was then used to generate a Venn diagram using the Bioinformatics and Evolutionary genomics webtool. Numbers occurring in nonoverlapping regions are unique to that specific passage. No mutation at either consensus or subconsensus level was shared across multiple lineages.