Evidence for phylogenetic inheritance in pathogenicity of Mycobacterium

In this study, we attempt to highlight part of the adaptive and phylogenetic constraints in mycobacterial pathogenicity. For this purpose, we first provide a phylogeny of Mycobacteria based on cladistic analyses of 64 different taxa. We then performed a comparative analysis, taking into account both ecological factors and phylogenetic relationships. The GLIM modelling analysis showed that different ecological and phylogenetic factors might be invoked to explain the variation in pathogenicity levels. Interestingly, the most harmful species were shown to be connected with the most diversified habitats. However, the independent contrast analysis revealed that once phylogeny was taken into account, none of the relationships between ecological factors and pathogenicity remained significant, and the pathogenicity appeared to be phylogenetically inherited among mycobacteria. The most pathogen were found in the slow-growing/long helix 18 group, and within this group in the most derived taxa.