Did viruses play a role in the extinction of Neanderthals? That’s what researchers from the Federal University of São Paulo have been trying to figure out, and in doing so, ended up uncovering the oldest known human viruses in a set of Neanderthal bones from over 50,000 years ago.
To make this finding, the team combed through the raw DNA sequencing data of two sets of Neanderthal remains recovered from Chagyrskaya cave in Russia. Within those raw sequences, they were looking for the remnants of the genomes – the entirety of an organism’s genetic information – of three types of DNA viruses: adenovirus, herpesvirus, and papillomavirus.
And they found them – remnants of all three groups, in fact. This makes the viruses the oldest human viruses ever discovered, taking the title away from those found in 31,600-year-old Homo sapiens remains.
This, the authors suggest in a preprint that’s yet to be peer-reviewed, demonstrated that not only was it feasible to identify bits of viral genomes in archaeological samples, but that Neanderthals could’ve been afflicted with the same viruses that affect humans today.
Adenoviruses, for example, can cause a wide range of illnesses from the pain in the butt that is the common cold, to a nasty bout of acute gastroenteritis. The overwhelmingly prevalent Epstein-Barr virus that can trigger mononucleosis and multiple sclerosis belongs to the herpesviruses. Papillomaviruses are perhaps best known for their association with cervical cancer.
It’s a possibility that Neanderthals may have been more susceptible to these three viruses and their effects.
There’s one limitation that palaeogeneticists must consider, though – contamination. What might look like a groundbreaking discovery could actually be the result of someone forgetting to cover their mouth when they cough, or an inquisitive (or hungry) animal.
Since they compared the ancient virus sequences with modern virus sequences to check for similarities and differences, this was most likely avoided.
“Taken together, our data indicate that these viruses might represent viruses that really infected Neanderthals,” study author Marcelo Briones told New Scientist.
That’s not to say that viruses alone may have caused the extinction of the Neanderthals, something the authors make clear in the paper, but it does at least add some weight to the theory of some scientists that viruses may have played some sort of role.
“To support their provocative and interesting hypothesis, it would be necessary to prove that at least the genomes of these viruses can be found in Neanderthal remains,” said Briones. “That is what we did.”
The study is available as a preprint on bioRxiv.
[H/T: New Scientist]
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