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Hannibal Lecter Would Not Have Been Happy
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| By:RANDOLPH E. SCHMID, Associated Press Writer |
April 10, 2003 |
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Prion resistance may be evidence of ancient cannibalism
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WASHINGTON - Cannibalism in ancient times may have caused epidemics of brain destroying diseases like kuru and Creutzfeld Jacob disease, a team of British researchers suggests.
Those two diseases and the human form of mad cow disease are believed to be caused by prions, an abnormal protein missing nucleic acid, that can cause proteins to clump in the brain. The diseases can be spread by eating flesh contaminated with prions.
But some people have gene mutations which protect them from those illnesses.
The research team led by John Collinge of University College in London reported in Friday's issue of the journal Science that that the protective genes, called polymorphisms, are mutant versions of the prion protein gene and show signs of having spread through the population through natural selection.
"What we're showing here is evidence that selection for these polymorphisms has been very widespread or happened very early in the evolution of modern humans, before human beings spread all over the planet," Collinge said in a statement. "We can't say which of those it is; but the obvious implication is that prion disease has provided the selection pressure."
Suggesting that cannibalism could have spread the diseases, increasing pressure to develop protective genes, the study cites the Fore people of Papua New Guinea, who were devastated by an epidemic of the prion disease kuru between 1920 and 1950.
It was their practice at mortuary feasts to consume deceased relatives until cannibalism was banned in the 1950s.
Collinge studied 30 women who had participated in these feasts and are still living, and found 23 had the genetic variation that protects against kuru.
It's the same genetic variation that helps protect against Creutzfeld Jacob disease, the study noted. The human form of mad cow disease is known as new variant Creutzfeld Jacob disease.
"There is extensive anthropological evidence that cannibalism is not just some rarity that happened in New Guinea," Collinge said. Other evidence of prehistoric cannibalism includes cuts and burn marks on Neanderthal bones and biochemical analysis of fossilized human feces.
Giuseppe Legname, a prion disease researcher at the University of California, San Francisco, called the paper intriguing but said he would like to see data from a larger population sample.
"We know ... that some polymorphisms make people resistant to prion diseases," he said. "But we need to learn more before we can draw any conclusions."
As far as cannibalism goes, he added, "that's something interesting. We don't have much information about prehistorical times and what were our ancestors' habits."
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