Viruses have represented a threat to human populations throughout history and still account for a large proportion of disease and death worldwide. Due to the long relationship between humans and viruses, gene variants conferring increased resistance to these pathogens have likely been targeted by natural selection. This concept has been exploited to identify variants in the human genome that modulate susceptibility to infection or the severity of the ensuing disease. Populations living in different geographic areas have been exposed to different viral loads and therefore have been subjected to a variable virus-driven selective pressure. By analysing genetic data for 52 populations distributed worldwide, scientists have identified variants that display higher frequency where the viral load is also high. Using this approach, they found 139 human genes that modulate susceptibility to viral infections; the protein products of several of these genes interact with one another and often with viral components.
Study Shows How Viruses Changed Human Evolution