London: Scientists have discovered a rare example of rapid human evolution by analysing a cannibalistic ritual in which the brains of dead tribespeople were eaten by
their relatives in Papua New Guinea.
In the middle of the 20th century, a mad cow or CDJ-like disease called kuru had devastated the Fore tribe of Eastern Highlands region of Papua New Guinea. But the tribes engaged in a rare ritual in which they ate the brains of the dead relatives to tackle the disease.
The practice was banned in the 1950s, but it left an imprint on their DNA.
Now a team of researchers led by Simon Mead from the Medical Research Council Prion Unit at University College London found a genetic mutation in the tribespeople that
protects them against the brain disease.
The resistant power has spread swiftly through the population by natural selection, The Times reported.
"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," the report said.
"It's fascinating to see Darwinian principles at work here. These 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," said director of the Prion Unit John Collinge.
PTI
First Published: Tuesday, November 24, 2009, 16:15