Fig. 2.

Distribution of genes present in the pan-genome of the NTHi collection (n=568), which was constructed using Roary version 3.12. Of 12 249 pan genes, the NTHi core-genome comprised 853 genes (present in at least 539 NTHi isolates). The remaining 11 396 genes of the accessory genome were further classified into the shell (n=1518 genes, present in less than 539 and at least 85 NTHi isolates) and cloud or unique (n=9878 genes, present in less than 85 NTHi isolates). On average, 47 % of each NTHi strain’s gene set belonged to the core pan-genome. The remaining 53 % of the strain’s gene set belonged to the larger accessory pan-genome. This accessory pan-genome encompassing a large repertoire of genes confers diversity and high levels of plasticity to the NTHi genome.