Figure 4

Ongoing reductive evolution in the ST260-261 lineage. (a) Distribution of insertions/deletions between strains 2-22 and A909, according to their sizes in nucleotides. Black bars correspond to sequences missing in the 2-22 strain compared to A909 and gray bars to sequences missing in A909 compared to strain 2-22. Only indels mapped in the core genome sequences are represented. b) Comparison of the number of indels and SNPs that occurred before (N_fbh-A_260+261 branch) and after sublineage separation (A_260+261-A₂₆₁ and A_260+261-A₂₆₀ branches). Indels and nucleotide changes relative to the A909 sequence were deduced from the comparison of the 15 strains shown in Figure 3. The mutation events were positioned on the phylogenetic tree according to a parcimonious approach. (c) Size distribution of the deletion events identified on the N_fbh-A_260+261, A_260+261-A₂₆₁ and A_260+261-A₂₆₀ branches respectively. Colors (red, green and blue) correspond to the branch colors of the tree presented in Figure 3.