A cannibalistic ritual in which the brains of dead tribespeople were eaten by their relatives has triggered one of the most striking examples of rapid human evolution on record, scientists have discovered.
In the middle of the 20th century the Fore tribe of the Eastern Highlands province of Papua New Guinea was devastated by a CJD-like disease called kuru, which was passed on by mortuary feasts in which the brains of the dead were consumed.
Although the practice was banned in the 1950s and kuru has disappeared, it has left an imprint on the tribe’s DNA.
Research has now identified a genetic mutation unique to the Fore that protects against the brain disease and which has spread swiftly through the population by natural selection.
As the mutation confers high or almost complete resistance to kuru, carriers have a survival advantage and have had more descendants.
About 8 per cent of people from the Purosa Valley region, where kuru hit hardest, now have the gene, which is unknown anywhere else in the world.