Oldest known human viruses found hidden within Neanderthal bones

Genetic analysis of 50,000-year-old Neanderthal skeletons has uncovered the remnants of three viruses related to modern human pathogens, and the researchers think they could be recreated.

Genetic sequences from three common viruses that plague humanity today have been isolated from the remains of Neanderthals who lived more than 50,000 years ago.

Neanderthals were affected by some of the same viruses as modern humans

Marcelo Briones at the Federal University of São Paulo, Brazil, says it may be possible to synthesise these viruses and infect modern human cells with them in the lab.

“These Jurassic Park-like viruses could then be studied for their reproductive and pathogenic traits and compared to present-day counterparts,” he says.

Briones and his colleagues analysed DNA from the skeletons of two male Neanderthals found in Chagyrskaya cave in Russia.

They identified the remnants of an adenovirus, which causes cold symptoms in modern humans; herpesvirus, which can result in cold sores; and the sexually transmitted papillomavirus, which can cause genital warts and cancer.

They are the oldest human viruses ever discovered, superseding a 31,000-year-old virus found in Homo sapiens teeth recovered from north-east Siberia.

Briones says by comparing the genetic sequences with modern viruses, the team has ruled out the possibility that the viruses came from contemporary humans who may have handled the remains or predators that may have fed on them.

“Taken together, our data indicate that these viruses might represent viruses that really infected Neanderthals,” he says.

Some researchers have speculated that viruses may have played a role in the Neanderthals’ extinction.

Briones says the team’s results add weight to the possibility, but cannot confirm it. “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,” he says. “That is what we did.”

The fact that a single Neanderthal could be infected with three viruses isn’t surprising, he says, since humans today are infected by about 10 different viral species, on average, during their lifespan.

Sally Wasef at Queensland University of Technology in Australia says the study suggests there is a high chance of further discoveries about past diseases that may have affected anatomically modern humans and our extinct human relatives.

However, the study of ancient viruses remains a new field that needs more exploration, she says. “The current tools used to authenticate ancient DNA results from humans might not apply to viruses, which have shorter DNA strands by default.”

Briones’s goal of recreating the ancient viruses will be challenging, she adds. “I am sceptical that this could be achieved given the lack of full understanding of how the viruses’ DNA is damaged and how to reconstruct the recovered pieces into a full viral genome. Also, the host-virus interaction, especially in a completely different environment, is something to consider.”


bioRxiv DOI: 10.1101/2023.03.16.532919

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