Human genomes carry traces of a 40-million-year-old animal virus that supposedly infected their ancestors, reported AFP.
Research published on Wednesday by the British science journal Nature said the invader is called bornavirus, a pathogen first identified in 1970s that infects the brain.
Keizo Tomonaga of Japan’s Osaka University headed up a team of scientists as they compared the DNA of a range of mammals, including humans, apes, elephants, marsupials and rodents, to look for markers of bornavirus code.
The team found several bornavirus fragments in the human genome in the form of two genes that may be functional, though they are still not clear on what they do.
Previously, the only viruses known to have been passed on in vertebrates were retroviruses, which work by commandeering cellular biological equipment in order to reproduce.
Retroviruses permeate the germline, or the DNA of reproductive cells, meaning at least part of their sequence is passed on to subsequent generations.
Some estimate that retroviruses are responsible for up to eight percent of the human genetic code for life.
Bornavirus, on the other hand, is a bit more furtive in its mode of operation; it replicates in the nucleus of infected cells.
Its name comes from the German town of Borna, where a regiment of cavalry horses was killed in 1885 by a mysterious “heated head” disease.
Following research also discovered the disease among sheep, llamas, ostriches, cats and cattle, although it is not well understood how it spreads.
The effect of the bornavirus on human genes will likely be up for dispute.
The greater question at hand is whether it gave potential cause of genetic mutation or innovation in our species, or if it provided a source for inherited illness or protection from illness.
While bornavirus has not been clearly linked to diseases in humans, some researchers theorize that there could be a connection to schizophrenia and other mental disorders.
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