A genetic mutation, CCR5Δ32, providing protection against HIV, originated approximately 9,000 years ago, potentially offering survival advantages to our ancestors and holding key insights into human evolution and disease resistance.
Researchers have pinpointed the origin and timeline of the CCR5Δ32 genetic variant. This mutation disables the CCR5 receptor, a protein used by HIV to enter immune cells, thus preventing infection in individuals with two copies of the mutation. It's found in 10-16% of the European population.
A study published in Cell analyzed 2,504 modern European and 934 ancient Eurasian genomes. Advanced DNA sequencing technology allowed researchers to overcome previous limitations due to fragmented ancient genomes. "By combining these data with our knowledge of human migrations at this time, we can also locate the region of origin of the mutation," explains Kristine Ravn, lead author.
Professor Simon Rasmussen states the variant emerged near the Black Sea between 6,700 and 9,000 years ago. This coincides with the arrival of early farmers in Europe from West Asia. The mutation's spread accelerated between 8,000 and 2,000 years ago, suggesting it aided populations migrating from the Eurasian steppe.
The CCR5 receptor helps regulate immune cell responses and direct them to sites of inflammation or infection. Leonardo Cobuccio suggests that individuals with the mutation may have survived better during exposure to new pathogens. As societies transitioned from hunter-gatherer to agricultural lifestyles, a more balanced immune system may have been advantageous.
The fact that this ancient genetic variation protects against a modern virus highlights unexpected connections between our evolutionary past and current health challenges. Understanding these connections can inform future strategies for combating infectious diseases and improving human health.