New Study Says Gut Bacteria Existed Even Before Human Did

First Posted: Jul 23, 2016 05:10 AM EDT

A new study has found that gut bacteria and microbes existed even before human beings came into being.

It was previously believed that most of the bacteria found in the gut came from the food and the surroundings. However, a new study claims that intestinal bacteria existed within humans even during the pre-human ape stage.

For the study, a team of researchers from the University of California, Berkely, analyzed gut bacteria in different ape species to understand their evolutionary relationship. They collected fecal samples of 47 Tanzanian chimps, 24 Congolese bonobos, 24 Cameroonian gorillas and 16 human beings from Connecticut, reported Tech Times.

The research team then performed genetic tests on three groups of bacteria- Bacteroidaceae, Bifidobacteriaceae and Lachnospiraceae- which constitute almost 20 percent of the human gut microbes.

It was found that the different bacteria existed in a common ancestor of human and great apes that lived more than 10 million years ago. It was when the common ancestor split into two distinct species that the gut bacteria also evolved into different strains linked to each host, reported The Guardian.

Around 15.6 million years ago, one such bacterial split happened when gorilla lineage diverged from the other hominids. Another bacterial split happened about 5.3 million years ago when human lineage separated from the lineage leading to chimps and bonobos.

Lead researcher Professor Howard Ochman said that it's surprising to know that gut microbes have been co-evolving inside human beings for a very long time.

Prof Andrew Moeller of the University of California, Berkeley who led the study, said "What's most exciting to me is the possibility that this codiversification between bacteria and hosts could extend much further back in time."

He added that there is a possibility that human gut microbes could be traced back to common ancestors with all mammals, all reptiles, all amphibians, maybe even all vertebrates. The research findings can help researchers better understand about human evolution.

Details of the study have been published in the journal Science.

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