Archaic human genes in the genome of modern human and the COVID-19 pandemic

Abstract

Palaeogenetic studies using high-throughput DNA sequencing revealed the genes of extinct human species in the genomes of modern humans. This is evidence of the crossing of our ancestors with the Neanderthal and Denisovian man in Asia and Europe. Moreover, this may indicate the adaptive benefits that modern man, occupying new geographic areas, gained as a result of acquiring new variants of genes from archaic species. One of the significant challenges our ancestors faced after leaving Africa were new pathogens, and viruses in particular. The analysis of modern genomes shows that genes inherited from our extinct relatives, coding for proteins of the immune system and proteins responsible for protection against viral infections, could help in the fight against them. It turns out that the genes present in the human genome, due to introgression, are also important in the confrontation with the SARS-CoV-2 virus, in particular, they affect the course of the COVID-19 disease. Interestingly, some of them, such as SLC6A20, LZTFL1, XCR1, and DPP4, may contribute to an increased risk of severe disease, while others, such as OAS1, OAS2, and OAS3, reduce this risk. Further research may shed light on the importance of these genetic variants in relation to past events that have led to an increase in their frequency in the genomes of modern humans. It is possible that viruses were an important selection factor that led to the presence of genes from extinct human species in the genomes of modern man, and these genes are evidence of past epidemics.