Our Ancestors Were Cannibals?
What we can learn about the Kuru virus...
The Fore tribe of Papua New Guinea practiced something in between ritual and survival cannibalism until the 1950s. Beginning in the 19th century, this group was partaking in ritual acts of mortuary cannibalism, which was later held to be responsible for the transmission of the fatal kuru epidemic. From approximately 1920 through the 1960s and epidemic of the prion disease kuru swept through the Fore, killing more than 200 people a year. Women and children were most vulnerable to the disease because they ate the most contaminated parts of the body- the brains, while men ate the best parts, including the muscle.
The brain diseases, called prion diseases, are characterized by loss of coordination, dementia, paralysis, and eventually death. The disease is caused by misshaped molecules that clump together and accumulate in brain tissue. These molecules are called prion proteins.
Scientists believe the misshapen prion proteins somehow cause normal prions to form incorrectly, making it easy for them to clump together. These clumps cause the formation of small cavities in the brain similar to holes in a sponge. Prion diseases are thought to be spread by eating the flesh of contaminated humans and animals and can also be passed down from one generation to the next through genetic inheritance. Humans with one normal copy and one mutated copy of the prion protein are protected against prion diseases. This polymorphism is found at a certain spot in the prion gene and is known as M129V. The study found that 23 out of the 30 women that had participated in the mortuary feast had one normal copy of the prion gene and one with the M129V polymorphism, suggesting that those who survived the kuru epidemic possessed a genetic resistance to the disease. (HTTP://new.nationalgeograhic.com/)
The study found this M129V polymorphism is present in every population worldwide, and they believe that this polymorphism arose more than 500,000 years ago. Cannibalism is the most likely explanation for their discovery, and genes that protect against brain diseases that can be contracted by eating contaminated flesh would have been adaptive in our human past. The disease has all but disappeared in New Guinea with the termination of cannibalism.