Genetic drift and purifying selection shape within-host influenza A virus populations during natural swine infections
Fig 4
Singly infected samples harbor relatively low levels of genetic diversity and show evidence of purifying selection.
(A) Distribution of the number of iSNVs identified per sample, across samples. (B) The proportion of detected iSNVs that fall below a given frequency, as specified on the x-axis. Approximately 70% iSNVs are detected at frequencies below 10%. Results are shown by sample lineage (I or II) and separately for nonsynonymous and synonymous iSNVs. (C) The ratio of the number of nonsynonymous to synonymous iSNVs, by gene segment and lineage. These ratios are shown alongside the neutral expectation, given by the ratio of nonsynonymous to synonymous sites. Black whiskers show the 95% confidence interval of the ratio.