Nature 555, 210–215 (2018).

Nature 555, 623–628 (2018).

There is an increasing understanding that the gut microbiome has a role in physiology and disease, although the relative contributions of the environment and genetics to its composition are unknown.

In one study, an international group of researchers analyzed the host genotypes and gut microbiomes of over 1,000 individuals who share a relatively similar environment. They found that host genetics has a minor role in determining microbiome composition and that diet, drugs and other anthropometric measures strongly influence interperson variability.

In another experiment, researchers based in Germany analyzed the effects of over 1,000 nonantibiotic drugs on the gut microbiome. Their analysis revealed that over 20% of these drugs inhibit the growth of bacterial species in the gut microbiome. Thus nonantibiotic drugs could play a role in antibiotic resistance by applying relevant selective pressure on bacteria and are also involved in shaping the gut microbiome.

Both studies reveal the large role of the environment in forming the gut microbiome.