Russian scientists in conjunction with colleagues from Denmark, Great Britain and Sweden found the most ancient evidence of people infection with viruses in Siberia. Researchers received the first direct evidence that the early people of the modern type suffered from herpesviruses and adenoviruses, which arose a few hundred thousand years ago and circulated in a human population at least with Pleistocene. This is reported in preprint of articles published in the Biorxiv repository.
Researchers analyzed DNA, which was allocated from human remains found on the Yanskaya parking lot in Yakutia, about 31 thousand years old. Here, on the site of archaeological excavations, three fragmented milk teeth belonging to children of 10-12 years old were discovered, while two teeth became a source of genetic material. Scientists conducted DNA sequencing by a shotgun when nucleic acids are randomly fragmented into small sections, which are then cloned and collected in an almost complete genomic sequence using algorithms.
Scientists have discovered DNA sequences that belonged to two families of DNA-containing viruses: adenoviruses (adenoviridae) and herpesviruses (Herpesviridae). At the same time, the researchers identified four different types of herpes virus, including cytomegalovirus, two types of Roseolovirus and SimplexVirus. In addition, each of the two teeth, which belonged to different children, was identified his adenovirus strain – HADVC1 and HADV-C2. All these viruses are able to cause chronic infections throughout the human life, and are dangerous in that they increase the risk of developing tumors.
Until now, the earliest evidence of viral infections of a person dated 6600 years ago, but the new discovery moved them to 25 thousand years in the past. Moreover, the analysis of molecular divergence between HADVC1 and HADV-C2 genomes showed that adenoviruses are very slowly evolving. Their overall ancestor existed about 700 thousand years ago, and the current genetic diversity of viruses is likely to precede the emergence of modern human genetic diversity, which has been established in the last 250 thousand years.
However, it is not yet known whether all the all species diversity of viruses appeared as a result of the migration of various viral lines together with groups of people from Africa in Eurasia, or there was an interspecan transfer from the archaic species of the genus Homo (Neanderthal and Denisovsky) to an anatomically modern man For mixing outside of Africa.