Did More Endorphins Make Us Human?

We may be getting closer to understanding some of the evolutionary changes that occurred between humans and our last common ancestor with chimpanzees. Surprisingly, it could involve changes in gene regulation, rather than in genes themselves. And even more surprisingly, one of the genes involved seems to be one for an opium-like protein.

"Perception" gene tracked humanity's evolution, scientists say

BLOOMINGTON, Ind. -- A gene thought to influence perception and susceptibility to drug dependence is expressed more readily in human beings than in other primates, and this difference coincides with the evolution of our species, say scientists at Indiana University Bloomington and three other academic institutions. Their report appears in the December issue of Public Library of Science Biology.

The gene encodes prodynorphin, an opium-like protein implicated in the anticipation and experience of pain, social attachment and bonding, as well as learning and memory.

"Humans have the ability to turn on this gene more easily and more intensely than other primates," said IU Bloomington computational biologist Matthew Hahn, who did the brunt of the population genetics work for the paper. "Given its function, we believe regulation of this gene was likely important in the evolution of modern humans' mental capacity."

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