(ORDO NEWS) — What makes modern people unique? This question has long been a driving force for researchers.
The size of the brain and the production of neurons are probably the main reasons for the increase in cognitive abilities that has occurred in the course of evolution.
Researchers at the Max Planck Institute for Molecular Cell Biology and Genetics (MPI-CBG) in Dresden, Germany have shown that the modern human variant of the TKTL1 protein, which differs from the Neanderthal variant by only one amino acid, significantly affects the number of radial glial cells in the modern human brain.
Neurons around the head
Basal radial glial cells generate the majority of neurons in the developing neocortex, a part of the brain that plays a role in complex cognitive processes.
And since TKTL1 activity is particularly high in the frontal lobe, the researchers concluded that this single human-specific amino acid substitution in TKTL1 explains why Homo sapiens have more neurons.
It is noted that earlier a comparison of the brain of a Neanderthal (Homo neanderthalensis) and a reasonable person (Homo sapiens) did not show any critical differences.
And the current study brings clarity, partly answering the question of how the number of neurons affects the development of mankind.
How the study was done
During the experiments, the scientists compared the two versions of TKTL1 and how they affect the production of neurons in the neocortex of mouse embryos.
Thus, the number of cells in radial glia increased with the introduction of the TKTL1 protein from Homo sapiens, while the version of the protein from Neanderthals did not change their number in any way.
Therefore, the brains of already grown laboratory mice with arginine-containing TKTL1 had a large number of neurons.
“Our work implies that the production of neurons in the neocortex during fetal development in modern humans is higher than in Neanderthals, especially in the frontal lobe,” said Wieland Hattner, who led the study.
“It is tempting to suggest that this contributed to the development of the cognitive abilities of modern man.”
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