The Gut Microbiota of Rural Papua New Guineans: Composition, Diversity Patterns, and Ecological Processes
•The fecal microbiota in PNG is more diverse but less individualized than in the US
•Most bacterial species are shared among PNG and the US, but abundance profiles differ
•Impact of lifestyle on ecological assembly processes might explain these patterns
•Westernization may decrease bacterial dispersal rates, altering microbiota structure
Although recent research revealed an impact of westernization on diversity and composition of the human gut microbiota, the exact consequences on metacommunity characteristics are insufficiently understood, and the underlying ecological mechanisms have not been elucidated. Here, we have compared the fecal microbiota of adults from two non-industrialized regions in Papua New Guinea (PNG) with that of United States (US) residents. Papua New Guineans harbor communities with greater bacterial diversity, lower inter-individual variation, vastly different abundance profiles, and bacterial lineages undetectable in US residents. A quantification of the ecological processes that govern community assembly identified bacterial dispersal as the dominant process that shapes the microbiome in PNG but not in the US. These findings suggest that the microbiome alterations detected in industrialized societies might arise from modern lifestyle factors limiting bacterial dispersal, which has implications for human health and the development of strategies aimed to redress the impact of westernization.