A groundbreaking study has traced the origins of a genetic mutation that helps protect against HIV, revealing it likely arose around 9,000 years ago in individuals near the Black Sea. The CCR5 delta 32 mutation, which disables the CCR5 protein used by many HIV strains to infect immune cells, first appeared during a period of significant human evolution, long before the virus itself was even known to humanity.
The study, published in the journal Cell, analyzed thousands of ancient and modern genomes to pinpoint when and where this crucial genetic variation first occurred. Researchers have now established that the mutation, which is found in 10 to 16 percent of European populations, emerged in a person living between 6,700 and 9,000 years ago. This discovery adds a new layer to our understanding of human evolution, suggesting that the mutation may have provided an immune system advantage in ancient populations, even before HIV existed.
HIV-Fighting Gene Emerged 9,000 Years Ago in the Black Sea Region
The CCR5 delta 32 mutation is an alteration of the CCR5 gene, which encodes a protein present on immune cells. Normally, the CCR5 protein acts as a gateway for HIV to enter these cells, but in individuals with the CCR5 delta 32 mutation, the protein is nonfunctional, rendering the virus unable to infect the cells. According to Simon Rasmussen, a bioinformatics expert at the University of Copenhagen, the mutation’s existence predates the modern HIV epidemic by millennia, meaning it must have served another evolutionary purpose, reports Live Science.
The research team, which included Rasmussen and several other experts, analyzed over 3,000 genomes from the 1000 Genomes Project, an international effort to catalog human genetic variation. They identified the mutation in both ancient and modern human genomes, enabling them to trace the mutation back to individuals who lived near the Black Sea during the transition between the Mesolithic and Neolithic periods. This finding challenges previous theories that linked the mutation’s spread to more recent historical events, such as the medieval plagues or Viking exploration.
Genetic Mutation Helped Early Humans Survive Deadly Pathogens
The researchers hypothesize that the mutation likely provided an advantage in combating other pathogens present during the time when it first appeared. The shift from hunter-gatherer lifestyles to agricultural societies exposed humans to new infectious diseases. According to Leonardo Cobuccio, a postdoctoral researcher at the University of Copenhagen, a more balanced immune system could have been advantageous during this period, as an overly aggressive immune response to new pathogens could have been detrimental.
This gene variant’s protective qualities likely helped early agricultural societies survive in environments filled with emerging diseases. While the precise cause of the mutation’s rise remains unclear, its increase in frequency across European populations between 8,000 and 2,000 years ago suggests it was a critical evolutionary adaptation during a time of significant societal and environmental change.
Forget the Black Death: HIV-Resistant Gene Originated in Prehistory
The findings of this study also challenge earlier assumptions about how the CCR5 delta 32 mutation became widespread. For years, researchers speculated that the mutation’s increase in frequency could have been a response to historical events like the Black Death or other pandemics that shaped the immune systems of survivors. However, the new evidence suggests that the mutation’s rise was tied to earlier periods, particularly when early farmers first began settling in Europe.
The mutation’s rapid increase over the past several millennia implies it played a significant role in early human survival. The researchers note that the mutation became more prevalent between 8,000 and 2,000 years ago, well before the HIV epidemic emerged.