October 1, 2022

Study reveals surprising differences in the brains of modern humans and Neanderthals | Neanderthals

Neanderthals have always been portrayed as our goofy cousins ​​and thugs. Now, groundbreaking research – although not confirming the stereotype – has revealed startling differences in the evolution of the brain of modern humans and Neanderthals.

The study involved inserting a Neanderthal brain gene into mice and rodents and creating “mini-brain” structures called organelles, grown in the lab from human stem cells. Experiments revealed that the Neanderthal version of the gene was linked to a slower creation of neurons in the cerebral cortex during development, which the scientists said could explain modern humans’ superior cognitive abilities.

“Welland Huttner, who led the work at the Max Planck Institute for Molecular Cells, said: biology and genetics. “We believe this is the first convincing evidence that modern humans were cognitively better than Neanderthals.”

modern man and Neanderthals They split into separate lineages about 400,000 years ago, with our ancestors remaining in Africa and Neanderthals moving north into Europe. About 60,000 years ago, the exodus of modern humans from Africa brought the two species to face again and intermarried – Modern humans of non-African heritage carry 1-4% of Neanderthal DNA. 30,000 years ago, though, our ancient cousins ​​disappeared as a distinct species, and the question of how we outgrew Neanderthals has remained a mystery.

“One tangible fact is that wherever Homo sapiens goes it will essentially outperform the other species there. It’s a little strange,” said Professor Laurent Nguyen, of the University of Liège, who was not involved in the latest research. [Neanderthals] They were in Europe long before us and could have adapted to their environment including pathogens. The big question is why will we be able to compete with them.”

Some argue that our ancestors had an intellectual advantage, but until recently there was no way to test the hypothesis scientifically. This changed in the past decade when scientists succeeded in sequencing Neanderthal DNA From a fossilized finger found in a Siberian cave, paving the way for new insights into how Neanderthal biology differed from that of Neanderthals.

Recent experiments focus on a gene, called TKTL1, involved in the production of neurons in the developing brain. The Neanderthal gene version differed by one letter from the human version. When introduced into mice, the scientists found that the Neanderthal variant led to the production of fewer neurons, particularly in the brain’s frontal lobe, where most cognitive functions are located. The scientists also tested the gene’s effect in rodents and blobs of lab-grown tissue, called organelles, that replicate basic structures of the developing brain.

“This shows us that although we don’t know how many neurons a Neanderthal brain has, we can assume that modern humans have more neurons in the frontal lobe of the brain, where [the gene’s] “Activity is the highest, from Neanderthals,” said Anneline Pinson, the study’s first author.

Chris Stringer, head of human origins research at the Natural History Museum in London, called the work “pioneering”, saying it set out to tackle one of the central puzzles of human evolution – why, with all of the previous diversity of humans, they are now the only ones left.

“Ideas came and went — better tools, better weapons, proper language, art and symbolism, better brains,” Stringer said. “Finally, this provides evidence as to why our brains were superior to those of Neanderthals.”

More neurons does not automatically mean a more intelligent type of human being, even though it dictates the brain’s basic computing power. Human brains contain twice as many neurons as chimpanzees and bonobos.

Nguyen said the latest work is far from conclusive evidence of the superiority of modern human intelligence, but it does show that Neanderthals had meaningful differences in brain development. “This is an interesting story,” he added.