Oxford University scientists found out that the most recent overall ancestor of SARS-COV-1 coronaviruses, which caused the outbreak of atypical pneumonia in 2002-2004, and SARS-COV-2, the causative agent of COVID-19, there was another 21 thousand years ago that Makes it almost 30 times ancient than in previous estimates. This is reported in the article published in the journal Current Biology.
Viruses are able to quickly evolve in a short time, but they must remain adapted to their owners, which imposes serious restrictions on freedom to accumulate mutations without reducing their fitness. This leads to a slowdown in the visible velocity of the evolution of viruses over time. A new study takes into account the patterns of the observed downturn in viruses, which allowed scientists to trace the evolution of coronaviruses to their ancestor forms.
Although the existing evolutionary models often do not allow to determine the divergence of virus species for periods from several hundred to several thousand years, a new evolutionary model allows you to reliably assess the time of the origin of new types of viruses in a time scale comparable to the evolutionary development of animals and plants.
Scientists are now capable not only to reconstruct the evolutionary history of viruses associated with SARS-COV-2, but also a much larger spectrum of RNA and DNA viruses in remote periods of the past. Prognostic models for hepatitis C virus are consistent with the idea that it circulates in human populations for almost half a million years. Thus, the hepatitis virus may have spread throughout the world due to the migration of people anatomically modern type from Africa about 150 thousand years ago.