Which gut bacteria are found across more mammal hosts?

Details

Different mammal species associate with distinct gut microbes, a pattern sometimes called phylosymbiosis. The processes shaping this host specificity are not well understood.

One model proposes that barriers to microbial transmission promote specificity by limiting dispersal between hosts. It predicts that microbial host specificity will be correlated with transmission mode—vertical versus horizontal—and individual dispersal traits.

To test this prediction, researchers analyzed two large publicly available gut microbiota datasets, comprising 1,490 samples from 195 host species. Host specificity varied widely among bacteria: some were generalists and others specialists, with specificity depending on transmission mode and dispersal ability. Bacteria with horizontal-like transmission and traits that facilitate switching between hosts, such as oxygen tolerance, were less host-specific than microbes without those traits, such as bacteria with vertical-like inheritance that are intolerant to oxygen.

The findings are compatible with a model in which limited microbial dispersal abilities foster host specificity.