Neanderthals have long been portrayed as our dumb, rogue cousins. Now, groundbreaking research has – without confirming the stereotype – revealed striking differences in the brain development of modern humans and Neanderthals.
The study involved inserting a Neanderthal brain gene into mice, ferrets and “mini-brain” structures called organoids, grown in the lab from human stem cells. The experiments revealed that the Neanderthal version of the gene was linked to slower creation of neurons in the cerebral cortex during development, which the scientists believe could explain the superior cognitive abilities in modern humans.
“Making more neurons lays the foundation for higher cognitive function,” said Wieland Huttner, who led the work at the Max-Planck Institute for Molecular Cell Biology and Genetics. “We believe this is the first compelling evidence that modern humans were cognitively better than Neanderthals.”
Modern humans and Neanderthals split into separate lineages around 400,000 years ago, with our ancestors remaining in Africa and Neanderthals moving north into Europe. About 60,000 years ago, a mass migration of modern humans out of Africa confronted the two species again and they interbred – modern humans of non-African descent carry 1-4% of the DNA of Neanderthal. 30,000 years ago, however, our ancient cousins had disappeared as a separate species, and the question of how we surpassed the Neanderthals remained a mystery.
“A concrete fact is that wherever homo sapiens would go, they would essentially outperform the other species there. did not participate in the latest research. “These guys [Neanderthals] were in Europe long before us and would have been adapted to their particularly pathogenic environment. The big question is why we would be able to surpass them.
Some claim that our ancestors had an intellectual advantage, but until recently there was no way to scientifically test the hypothesis. That changed over the past decade when scientists successfully sequenced Neanderthal DNA from a fossilized finger found in a Siberian cave, paving the way for new insights into the difference between Neanderthal biology and ours.
The latest experiments focus on a gene, called TKTL1, involved in neuronal production in the developing brain. The Neanderthal version of the gene differs by one letter from the human version. When inserted into mice, scientists found that the Neanderthal variant resulted in the production of fewer neurons, particularly in the frontal lobe of the brain, where most cognitive functions reside. The scientists also tested the gene’s influence on ferrets and lab-grown drops of tissue, called organoids, which replicate the basic structures of the developing brain.
“This shows us that even though we don’t know how many neurons the Neanderthal brain had, we can assume that modern humans have more neurons in the frontal lobe of the brain, where [the gene’s] the activity is higher than that of Neanderthals,” said Anneline Pinson, first author of the study.
Chris Stringer, head of human origins research at the Natural History Museum in London, called the work “pioneering”, saying it has begun to solve one of the central enigmas of human evolution – why, with all the past diversity of humans, we are now the only ones left.
“Ideas have come and gone – better tools, better weapons, appropriate language, art and symbolism, better brains,” Stringer said. “Finally, this provides a clue as to why our brains might have surpassed those of Neanderthals.”
More neurons does not automatically equate to a smarter type of human, although it does dictate the basic computational ability of the brain. The human brain contains about twice as many neurons as the brains of chimpanzees and bonobos.
Nguyen said the latest work is far from definitive proof of modern humans’ superior intellect, but does demonstrate that Neanderthals had significant differences in brain development. “It’s an exciting story,” he added.
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