Humans and Neanderthals could have more in common than just DNA – we also might share the microorganisms in our gut.
An international team of scientists led by Marco Candela, from the University of Bologna in Italy, have discovered that the gut microbiota of Neanderthals includes several beneficial microorganisms that also exist in modern humans.
To figure this out, they extracted and analysed ancient fragments of DNA from 50,000-year-old samples – of Neanderthal fecal matter.
“Through the analysis of ancient DNA, we were able to isolate a core of microorganisms shared with modern Homo sapiens,” explains Silvia Turroni, co-author from the University of Bologna.
“This finding allows us to state that these ancient microorganisms populated the intestine of our species before the separation between Sapiens and Neanderthals, which occurred about 700,000 years ago.”
The results are published in the journal Communication Biology.
Our gastrointestinal tract is home to trillions of microscopic organisms, which live in symbiosis with us and perform many important functions, like regulating our metabolism and immune system.
But research has shown that modern life – through factors such as processed foods, drug use and living in sanitised environments – is progressively reducing the biodiversity of these communities. This is a problem, as many of these tiny critters are crucial to human physiology.
This study therefore set out to identify the parts of our gut microbiota that are most important to our health – that is, the core components that have remained consistent as we evolved.
To do so, they collected sedimentary faeces – the oldest ever found – from a site called El Salt in Spain, which is known to have been frequented by several species of ancient humans over thousands of years. They then amplified the small amounts of DNA found in the sample and sequenced it to piece together the composition of Neanderthal microbiota.
When the team compared this to our own biota, they spotted many similarities – what they call “ancestral” components – including many well-known bacteria such as Blautia, Dorea, Roseburia, Ruminococcus, Bifidobacterium and Faecalibacterium.
“These results allow us to understand which components of the human gut microbiota are essential for our health, as they are integral elements of our biology also from an evolutionary point of view,” explains lead author Candela.
He adds that their result could guide us in devising diet- and lifestyle-tailored solutions to counteract the reduction of our microbiota diversity.
Related reading: Closer to Neanderthals than we thought
Lauren Fuge is a science journalist at The Royal Institution of Australia.
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