Frequency distribution of homology groups.

<p>Dark shading indicates HGs for which myRAST identified a function, lighter shading were identified only as “hypothetical proteins”. Strain-specific genes are indicated by the leftmost bar (a), and character HGs (b) are between strain-specific genes and HGs of the extended core (c). The strict core genome is made up of HGs present in all 37 strains (d). Although relatively few genes per genome (<math><mrow><mi>x</mi><mo>¯</mo> <mo>=</mo> <mn>153</mn></mrow></math>) are strain-specific, the cumulative total across the pangenome is high.