Fig. 6

Relationships between inter-phylogroup recombination, virulence-association (“ecologically significant” loci), and positive selection (“evolutionarily significant” loci) for genes in P. syringae based on chi-squared proportions tests. Bars represent the percentage of total genes in each category and absolute values are inside each bar. There is no significant association between positively selected and virulence-associated genes (a). However, there is a significant positive association between gene families that have undergone inter-phylogroup recombination with virulence-associated gene families (b), positively selected gene families (c), and the small collection of gene families that are both virulence-associated and positively selected (d). The Venn diagram (e) depicts the number gene families undergoing inter-phylogroup recombination, the number of gene families that are virulence associated, and the number of gene families that are positively selected, as well as the significance of the overlap between these families