Fig. 7: Copy number diversification in vivo.

a–c Six-week old female C57BL/6 mice were challenged with S. aureus live bacteria that carried either a functional csa1::tetK locus (a) or an inactivated csa1(FS)::tetK locus (b, c). Mice were sacrificed 24 h or 48 h post infection as indicated. High Tc resistant clones arising from the input culture and from mouse kidneys were enumerated and csa1 (a) or csa1(FS) (b, c) gene copy number was determined. Horizontal lines show the median. Up to 19 arising clones were screened. No Tc₂₀ resistant clones were recovered from mouse 4 and mouse 2 in (b) and (c), respectively. Source data are provided as a Source Data file. d Frequency of amplification in mouse organs. qPCR analysis was used to calculate the frequency of amplification within each mouse (number of Tc₂₀-resistant clones that showed at least a 2 fold increase in csa1 or csa1(FS) copy number compared to the parental strain within the total population of living cells recovered from each mouse) (dark-filled dots). x indicates a mouse in which amplification was not detected. Six mice were used in each group. Source data are provided as a Source Data file. e C57BL/6 mice were infected either with a low copy number variant (~4 copies) or a high copy number variant (~100 copies) of csa1 genes. Mice were sacrificed 72 h post infection and CFUs within the kidneys and spleen were enumerated. Horizontal lines show the median. Statistical analysis was performed using two-tailed Mann–Whitney test, but no significant differences were found. Six mice were used in each group. Source data are provided as a Source Data file.