Scientists have discovered an old virus that dates back to the dinosaur era in an unexpected area. It’s sort of lurking in broad daylight in the human DNA, explains University of Oxford’s Aris Katzourakis. Every live person has two copies of a long-extinct virus.
The viruses that infect us with anything from Covid-19 to the ordinary cold are significantly different from the ones that infect us now. Retroviruses, which proactively insert DNA replicas of their RNA genes into the genomes of the cells they infect, are the most common types of modern viruses. Between 5% and 10% of the human genome is made up of “junk DNA” from retroviruses.
The newly found fossil viruses are members of an old category of DNA viruses identified as Mavericks by scientists. Traces of prehistoric Mavericks have previously been found in fish, amphibians, and reptiles, but the only other known instance of Maverick DNA within mammals is in cast, which is likely to have been contaminated by fish. However, these old viral remnants have always been present.
Katzourakis, along with his co-author Jose Gabriel Nino Barreat, claim that one of the Maverick viruses was integrated into the genome of one of our ancient predecessors at least 105 million years ago in a recent publication reporting the finding. They also put the viral ancestor’s age at roughly 268 [million years].
The findings support some of the earliest viral integrations in the human genes and provide light on early viral interactions with mammalian progenitors.
In the human genome, there aren’t very many non-retroviral viruses, Katzourakis explained to New Scientist. We are aware of just one DNA virus in the human genome, and it is unquestionably the earliest non-retroviral introduction in our genomes.
