A cannibalistic ritual in which the brains of dead tribes people 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 mad cow-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 tribe that protects against the brain disease, which has spread swiftly through the population by natural selection.
The findings, from a team led by Simon Mead, of the Medical Research Council Prion Unit at University College London, show how quickly human evolution can respond to new environmental pressures.
“It’s absolutely fascinating to see Darwinian principles at work here,” professor John Collinge, the director of the unit said. “This community of people have developed their own biologically unique response to a truly terrible epidemic. The fact that this genetic evolution has happened in a matter of decades is remarkable.”
The research is also significant because it promises to shed light on the proteins that cause Creutzfeldt-Jakob disease or the human form of mad cow disease.