Neanderthals have long been portrayed as our stupid, murderous cousins. Now, groundbreaking research — while not substantiating this stereotype — has revealed striking differences in brain development between modern humans and Neanderthals.
The research involved inserting Neanderthal brain genes into mice, ferrets and “mini-brain” structures called organoids, which were grown in the lab from human stem cells. Experiments have shown that the Neanderthal version of the gene is associated with slower production of neurons in the developing cerebral cortex, which scientists say could explain the superior cognitive abilities of modern humans.
“Making more neurons lays the foundation for higher cognitive function,” said Wieland Hertner, who led the work at the Max Planck Institute for Molecular Cell Biology and Genetics. “We think this is the first convincing evidence that modern humans were cognitively better than Neanderthals.”
About 400,000 years ago, modern humans and Neanderthals split into separate lineages, with our ancestors staying in Africa while Neanderthals migrated north to Europe. About 60,000 years ago, with the mass migration of modern humans out of Africa, the two species came face-to-face again and interbred—modern humans of non-African ancestry carry 1-4% Neanderthal DNA. However, by 30,000 years ago, our ancient cousins had disappeared as a distinct species, and the question of how we outcompeted Neanderthals remained a mystery.
“A concrete fact is that wherever Homo sapiens go, they basically outcompete other species out there. It’s a little strange,” said Professor Laurent Nguyen of the University of Liege, who was not involved in the latest research. “These guys [Neanderthals] It was in Europe long before us and had adapted to the environment including pathogens. The big question is why are we able to out-compete them. “
Some believe our ancestors had an intellectual advantage, but until recently there was no way to test this hypothesis scientifically. That has changed over the past decade, as scientists have successfully sequenced Neanderthal DNA from fossilized fingers found in Siberian caves, providing insights into Neanderthal biology versus ours What a difference paves the way.
The latest experiments focused on a gene called TKTL1, which is involved in the production of neurons 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 resulted in fewer neurons being produced, particularly in the frontal lobe of the brain, where most cognitive functions reside. The scientists also tested the gene’s effect on ferrets and lab-grown tissues called organoids, which replicate the basic structure 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 had more neurons in the frontal lobes, where [the gene’s] activity was highest in Neanderthals,” said Annelyn Pinson, lead author of the study.
Chris Stringer, head of human origins research 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 there was so much diversity in the human past , we are now the only ones left.
“Ideas come and go — better tools, better weapons, the right language, art and symbolism, better brains,” Stringer said. “In the end, this provides a clue as to why our brains may have been superior to Neanderthal brains.”
More neurons does not automatically equate to a smarter human type, although it does determine the brain’s basic computing power. There are about twice as many neurons in the human brain as in the brains of chimpanzees and bonobos.
The latest research is far from clear evidence of the superior intelligence of modern humans, but shows striking differences in brain development among Neanderthals, Nguyen said. “It’s an exciting story,” he added.