The international group of scientists has discovered evidence of the epidemic of an unknown coronavirus or the pathogen similar to it, which struck the region of East Asia more than 20 thousand years ago. Genetic flames of the outbreak are still present in the genomes of people living in this region. The results of the study are published in the journal Current Biology.
Researchers analyzed the project data 1000 Genomes Project, which is the largest publicly available catalog of common genetic variations of a person. Their goal was to find out whether the ancient coronavirus epidemics is indeed, if such were, could somehow influence the susceptibility of the person to the effects of viruses, including SARS-COV-2, currently.
It is known that natural selection in the past contributed to the spread of such genes in the human population, which coded proteins, physically interacting with viruses (VIRUS-INTERACTING PROTEINS, VIP) and contributing to protection against infections, reducing the severity of diseases. Scientists were looking for characteristic traces of such selection in 420 proteins interacting with coronavirus (COV-VIP), among 26 different human populations.
Among all COV-VIPs 332, the protein was interacted with SARS-COV-2, and 88 were mentioned in scientific literature as associated with various coronavirus infections (SARS-COV-1, MERS and HCOV-NL63, causing moderate ARVI). It turned out that the frequency of such genes was significantly increased in many populations of East Asia, which is not observed in other groups of people. This indicates the occurrence of other coronavirus epidemics in the region in the past.
so, 42 genes associated with coronavirus were subjected to a coordinated natural selection of about 25 thousand years ago, which corresponds to about 900 generations. However, researchers cannot exclude that the reason for the selection could be another unknown type of viruses, which interacted with human proteins as well as coronaviruses.
among these 42 COV-VIPs turned out to be many of those options that influence the flow of COVID-19 among the modern population. Mutations with providers or, on the contrary, protective effects, affect the fragments of genes, which are located next to the regulatory areas, active in the lungs and other tissues that SARS-COV-2 affect. At the same time, the authors of the article emphasize that the results do not represent evidence of any differences in increased or reduced genetic susceptibility in any human population.
All modern coronavirus flashes, including SARS, MERS and COVID-19, occur from East Asia. As the study shows, this region probably served as a natural reservoir of coronaviruses in the last 25 thousand years.