FIG 1.

Phenotypic and genotypic effects of a natural heterozygous SNP in the oriV of pB1000. A heterozygous SNP in the oriV of pB1000 produces an increase in PCN, which leads to a higher ampicillin resistance level and to an increase in the metabolic cost of the plasmid. (A) Chromatograms of the different variants (A3880, C3880, and A3880 plus C3880 in heterozygosis). Notice that the corresponding substitutions are highlighted in bold red letters in the chromatograms. M denotes the heterozygosity of variants A and C. (B) Correlation between the plasmid copy number and resistance level (left) and between the plasmid copy number and relative fitness w (right). Black, white, and black-white dots denote strains bearing variant A3880, variant C3880, and both variants in heterozygosis, respectively. Bars represent the SEMs.