Research indicates what advantage modern humans had over Neanderthals

By studying fossilized skulls, scientists know that the brain size of a Neanderthal was the same, if not slightly larger, than that of a modern human. However, researchers know little about Neanderthal brain development because soft tissue does not preserve itself well in the fossil record.

Now, an intriguing study released on September 8 has revealed a potential difference that may have given modern humans, or Homo sapiens, a cognitive advantage over Neanderthals, the Stone Age hominids that lived in Europe and parts of Asia before they were born. extinct about 40,000 years ago.

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

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

When the two versions of the gene were inserted 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 genetic variants in ferret embryos and lab-grown brain tissue made from human stem cells, called organoids, with similar results.

The team argued that this ability to produce more neurons likely gave Homo sapiens a cognitive advantage unrelated to overall brain size, suggesting that modern humans have “more neocortex to work with than ancient Neanderthals,” according to the published study. in Science magazine.

“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 higher, than Neanderthals,” Huttner explained.

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

“But we don’t need to care because (from this research) we know that modern humans must have more neurons in the frontal lobe. […] and we think this is a boon for cognitive abilities.”

“Premature” Discovery

Alysson Muotri, professor and director of the Stem Cell Program and Archaealization Center at the University of California at San Diego, said that while the animal experiments revealed “quite a dramatic difference” in neuron production, the difference was more subtle in organoids. . He did not participate in the research.

“This has only been done on one cell line, and as we have huge variability with this brain organoid protocol, it would be ideal to repeat the experiments with a second cell line,” he said by email.

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

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

Archaeological discoveries in recent years have suggested that Neanderthals were more sophisticated than pop culture depictions of brutal cavemen might suggest. Our ancient relatives knew how to survive in cold and hot climates and used complex tools. They also made yarn, swam and created 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.

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