Figure 6.

Plasmid copy numbers per bacterial cell

(A–D)Average proportions of sequences mapping against the CO92 circular chromosome (A) and the plasmids (B, C, and D) for the different archaeological sites from the 17^th c. CE (orange, Amiens, Beauvais, and Lariey) and the 18^th c. CE (light brown, La Major, and Les Rayettes). Probe proportions targeting the CO92 genome and the three plasmids are indicated by the brown bars. Data are represented as mean ± SEM. Statistically significant values (Wilcoxon test) for inter- and intra-century comparisons are indicated. Only those libraries prepared on the DNA extracted following 1-h pre-digestion were considered to avoid technical batch effects, disregarding those for which an insufficient number of high-quality read alignments could be identified (i.e. < 500).