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After year 0, we no longer see signs of a positive selection.
But by then, the variant was well established in Northern Europe—and it remains there today.
After year 0, we no longer see signs of a positive selection.
But by then, the variant was well established in Northern Europe—and it remains there today.
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Here’s the wild part:
A mutation that damages an immune gene sounds bad.
But in the context of evolving human societies, it might’ve been a life-saving adaptation.
Think of allergic reactions or COVID-19:
It’s often not the virus, but the immune system overreacting, that causes the most damage.
CCR5delta32 may have helped tune immune balance in a world where infections were more common.
HIV appeared in the 20th century.
That a Neolithic mutation offers protection against a modern virus is a testament to evolution’s strange, serendipitous logic.
So if you’re one of the millions of Europeans who carry this variant—
You share a direct genetic link to a single ancient human whose mutation reshaped immune defenses across Europe.
Thanks for reading!
Paper (open access): https://doi.org/10.1016/j.cell.2025.04.015
Lead authors: Kirstine Ravn, Leonardo Cobuccio, Rasa Muktupavela, Evan Irving-Pease
Affiliations: University of Copenhagen,
Bonus technical details:
We found that CCR5delta32 sits on a specific haplotype — “Haplotype A” — comprising 86 tightly linked variants.
We identify two ancestral haplotypes (B and C) that were widespread long before CCR5delta32 emerged on the haplotype B.