Exploring clade differentiation of the Faecalibacterium prausnitzii complex

Faecalibacterium prausnitzii is one of the most prevalent and abundant polyphyletic health-promoting components of the human gut microbiome with a propensity for dysbiotic decreases. To better understand its biology in the human gut, we specifically explored the divergence pressures acting on F. prausnitzii clades on a global scale. Five F. prausnitzii clades were de novo identified from 55 publicly available genomes and 92 high-quality metagenome assembled genomes. Divergence rate indices were constructed and validated to compare the divergence rates among the different clades and between each of the diverging genes. For each clade we identified specific patterns of diverging functionalities, probably reflecting different ecological propensities, in term of inter-host dispersion capacity or exploitation of different substrates in the gut environment. Finally, we speculate that these differences may explain, at least in part, the observed differences in the overall divergence rates of F. prausnitzii clades in human populations.