Differences in human and Neanderthal brains revealed

Now, an intriguing study released Sept. 8 has uncovered a potential difference that gave modern humans, or Homo sapiens, a cognitive advantage over Neanderthals, the Stone Age hominids living in Europe and parts of Europe. Asia lived before they became extinct about 40,000 years ago.

Scientists at the Max Planck Institute for Molecular Cell Biology and Genetics in Dresden, Germany, said they have identified a genetic mutation that caused the faster production of neurons in the Homo sapiens brain. The Neanderthal variant of the gene in question, known as TKTL1, differs by one amino acid from the modern human variant.

“We identified a gene that contributes to becoming human,” said study author Wieland Huttner, professor emeritus and director of the institute.

When the two versions of the gene were introduced into mouse embryos, the research team found that the modern human variant of the gene resulted in an increase in a specific type of cell that creates neurons in the neocortex region of the brain. The scientists also tested the two gene variants in ferret embryos and lab-grown brain tissue made from human stem cells called organoids with similar results.

The team reasoned that this ability to produce more neurons likely gave Homo sapiens a cognitive edge unrelated to total brain size, suggesting that modern humans “have more neocortex to work with than the ancient Neanderthal,” according to the study published. in the journal Science.

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“This shows us that while 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 TKTL1 activity is highest, than Neanderthals,” explained Huttner. from.

“There has been some debate about whether or not the frontal lobe of Neanderthals was as large as that of modern humans,” he added.

“But we don’t need to worry because we know (from this study) that modern humans must have had more neurons in the frontal lobe … and we think that’s an advantage for cognitive skills.”

‘Premature’ finding

Alysson Muotri, professor and director of the Stem Cell Program and Archealization Center at the University of California San Diego, said that while the animal studies revealed a “pretty dramatic difference” in neuron production, the difference was more subtle in the organoids. . He was not involved in the investigation.

“This was done in only one cell line and since we have tremendous variability with this brain organoid protocol, it would be ideal to repeat the experiments with a second cell line,” he said via email.

It was also possible that the archaic version of the TKTL1 gene was not unique to Neanderthals, Muotri noted. Most genomic databases focus on Western Europeans, and it’s possible that human populations in other parts of the world share the Neanderthal version of that gene.

“I think it’s rather premature to suggest differences between Neanderthal and modern human cognition,” he said.

How Neanderthal DNA affects human health - including the risk of getting Covid-19
Archaeological finds in recent years have suggested that Neanderthals were more sophisticated than pop culture depictions of brutal cavemen suggest. Our old relatives knew how to survive in cold and hot climates and used complex tools. They also made yarn, swam and made art.

Study co-author and geneticist Svante Pääbo, director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, pioneered efforts to extract, sequence and analyze ancient DNA from Neanderthal bones.

His work led to the discovery in 2010 that early humans interbred with Neanderthals. Scientists then compared the Neanderthal genome with the genetic data of living humans today to see how our genes overlap and differ: TKTL1 is just one of dozens of identified genetic differences, while some shared genes may have implications for human health. .

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