In the article, "Humans evolved with their microbiomes," Ley and Suzuki describe that bacteria have not only evolved in parallel with their early human hosts. Settling in different parts of the world and the respective adaptation of hosts and bacteria to changing environmental conditions is only one aspect of bacterial evolution, they say. Some of these bacteria have become dependent on their host, limiting their survivability over time to the human gut.
Ley and Suzuki are referring to their recent study, published in the journal Science, which they conducted in collaboration with researchers from the Cluster of Excellence CMFI and the University of Tübingen's Tropical Medicine Institute.
For the study, the research team analyzed the gut microbiomes and genomes of 1225 individuals in Europe, Asia and Africa with partner organizations in Vietnam and Gabon.