The Guardian reports: The evolutionary history of the bacteria in your guts predates the appearance of humans, and mirrors that of our great ape relatives, according to a genetic study.

The research suggests that microbes in our ancestors’ intestines split into new evolutionary lineages in parallel with splits in the ape family tree.

This came as a surprise to scientists, who had thought that most of our gut bacteria came from our surroundings – what we eat, where we live, even what kind of medicine we take. The new research suggests that evolutionary history is much more important than previously thought.

“When there were no humans or gorillas, just ancestral African apes, they harboured gut bacteria. Then the apes split into different branches, and there was also a parallel divergence of different gut bacteria,” said Prof Andrew Moeller of the University of California, Berkeley who led the study, published in Science. This happened when gorillas separated somewhere between 10-15 million years ago, and again when humans split from chimps and bonobos 5 million years ago. [Continue reading…]