Chimpanzees and humans share not only 96% of their DNA sequence, but also the basic make-up of their gut microbes.

The microbial communities that thrive in the human gut can typically be grouped into three 'enterotypes', each of which is dominated by a specific set of bacteria. Howard Ochman at Yale University in New Haven, Connecticut, and his colleagues categorized the enterotypes of 35 chimpanzees from Gombe Stream National Park in Tanzania. Between them, the chimpanzees also harboured three enterotypes, and these were similar in composition to those found in humans.

The results suggest that this variation in gut microbial groups is an ancient trait that preceded the split between humans and chimpanzees.

Nature Commun. 3, 1179 (2012)