Scientists from England, Australia, and Papua New Guinea say that cannibalism is the most likely explanation for their discovery that genes protecting against brain diseases that can be contracted by eating contaminated flesh have long been spread throughout the world.
A growing body of evidence, such as piles of human bones with clear signs of human butchery, suggests cannibalism was widespread among ancient cultures. The discovery of this genetic resistance, which shows signs of having spread as a result of natural selection, supports the physical evidence for cannibalism, say the scientists.
"We don't in fact know that all populations did select. The selection may have occurred during the evolution of modern humans before they spread around the world," said Simon Mead, a co-author of the study from the Medical Research Center with University College, London.