The community of bacteria that live on and in our bodies—the microbiome—plays an important role in our health. However, elements of modern Western lifestyles, such as Cesarean childbirth and the use of antimicrobial products, cut down on those microbial communities.

Maria Gloria Dominguez-Bello and colleagues chronicled the microbiome of people living in an isolated Yanomami village in the Venezuelan Amazon that had no previous documented contact with Western people. They found that the microbiome of those people contained the highest levels of bacterial diversity ever reported in a human group. Intriguingly, some of the bacteria studied carry genes that code for antibiotic resistance, even though the Yanomami people haven’t been exposed to commercial antibiotics.