Mutation counts and rates in viral clones.

Complete genome sequences were determined for 10 SARS-WT and 10 S-ExoN1 P3 viral clones. Numbers of total (A) or unique (B) non-engineered nucleotide substitutions identified in SARS-WT and S-ExoN1 genomes are indicated. Each circle represents the mutation count value from a single genome sequence and lines indicate mean mutation counts. Rates of accumulation of unique substitutions per replication cycle on a per nucleotide (C) or per genome (D) basis. Mean values are plotted and error bars indicate standard deviations. *, P<0.0005; Wilcoxon rank-sum test.