Neanderthals have long been portrayed as our diminutive, brutish cousins. Now groundbreaking research – although not confirming the same pattern – has revealed significant differences in brain development in modern humans. Neanderthals.
The study involved inserting Neanderthal brain genes into mice, ferrets and “mini brain” structures called organoids grown in the lab from human stem cells. Experiments revealed that the Neanderthal version of the gene was associated with a slower generation of neurons in the brain’s cortex during development, which could explain the superior cognitive abilities of modern humans, the scientists said.
“Making more neurons forms the basis for greater cognitive function,” said Wieland Huttner, who led the work at the Max-Planck-Institute of Molecular Cell. Biology and genetics. “We think this is the first evidence that modern humans are cognitively superior to Neanderthals.”
Modern humans and Neanderthals Splitting into separate lineages about 400,000 years ago, our ancestors stayed in Africa and Neanderthals moved north into Europe. About 60,000 years ago, the mass migration of modern humans out of Africa brought the two species face to face once again, and they interbred – Modern humans of non-African heritage carry 1-4% Neanderthal DNA. By 30,000 years ago, however, our ancient relatives disappeared as a distinct species, and the question of how we outcompeted the Neanderthals remains a mystery.
“One concrete fact is that wherever Homo sapiens go they will basically compete with other species. This is a bit different,” said Professor Laurent Nguyen of the University of Liège, who was not involved in the latest research. [Neanderthals] existed in Europe long before us and would have adapted to their environment, including pathogens. The big question is why we can compete with them.
Some argue that our ancestors had an intellectual edge, but until recently there was no way to scientifically test this hypothesis. This changed in the last decade when scientists successfully sequenced Neanderthal DNA A fossilized finger found in a Siberian cave has led to new insights into how Neanderthal biology differed from our own.
Recent experiments have focused on a gene called TKTL1, which is involved in neuron production in the developing brain. The Neanderthal version of the gene differs from the human version by one letter. When inserted into mice, the scientists found that the Neanderthal variant led to the production of fewer neurons, particularly in the frontal lobes of the brain, where most cognitive functions are located. The scientists also tested the gene’s influence on ferrets and blobs of lab-grown tissue called organoids, which mimic the basic structures of the developing brain.
“Although we don’t know how many neurons were in the Neanderthal brain, this shows us that modern humans have more neurons in the frontal lobes of the brain. [the gene’s] Activity is much higher than Neanderthals,” said Annelyn Pinson, first author of the study.
Chris Stringer, head of research into human origins at the Natural History Museum in London, described the work as “groundbreaking”, saying it began to address one of the central puzzles of human evolution – why, with the diversity of humans in the past, we are now only a remnant.
“Ideas have come – better tools, better weapons, the right language, art and code, better brains,” Stringer said. “Finally, it’s a clue as to why our brains worked better than Neanderthals.”
More neurons does not automatically equal smarter humans, although it does dictate the brain’s basic computing ability. The human brain has twice as many neurons as the brains of chimpanzees and bonobos.
The recent work is far from definitive proof of modern humans’ superior intelligence, but demonstrates that Neanderthals had meaningful differences in brain development, Nguyen said. “It’s an amazing story,” he added.