A simple permutation in the composition of a cerebral protein could explain a more abundant production of neurons in the front of our cortex than in that of Neanderthal.
by
The brain is a fragile clusters of cells, there are therefore Neanderthals only empty skulls: impossible to know directly how their brains were made and how our gray matter of modern human is distinguished. But researchers from the Max-Planck Institutes, in Germany, have identified a difference between our genome and that of Neanderthal which could be an increase in increased cognitive capacities compared to our missing cousin. Their work has just been published in the journal window Science .
“In 2014, Svante Paabo [Max-Planck Institute, Leipzig], with whom we collaborated, published the complete sequence of the genome of a Neanderthal of Siberia, in which a gene had been identified as a possible candidate to explain A brain development different from that of Homo Sapiens “, retraces Wieland Huttner (Max-Planck Institute, Dresden), specialist in the human brain and the last author of this new study. This gene is responsible for the production of a protein – named TKTL1 – presenting a single difference between these two species of the genus Homo: in the amino acid chain which constitute TKTL1, a lysine, present in Neanderthal, has been replaced, in sapiens, by a arginine.
A mutation certainly punctual but whose consequences are not to be minimized. Already, in 2020, the Wieland Huttner team had published the case of another gene which presented only one change between species of the genus homo and non -human primates. However, this simple protein variation made it possible to explain the difference in size between human brains, larger than those locked up in seated skulls.
a increased production of neurons
Nevertheless, even if they have brains of comparable size, Sapiens and Neanderthals may not have similar cognitive capacities. Indeed, the TKTL1 protein is particularly abundant in the front of the cerebral neocortex, also more commonly known as “gray matter”. And according to the results obtained by the German team, the mutation observed in TKTL1 would promote a multiple production of neurons during the development of our brain.
More precisely, the protein would play a role in the metabolic pathways at the origin of the neural progenitor cells, of the cells which, by dividing, form the neurons. “In particular there are two classes of progenitor cells: intermediate cells and radial glial cells, details Anneline Pinson, postdoctoral and first author of the study. While the former only divided once to lead to two neurons, The seconds are asymmetrically divided into a neuron and a new progenitor cell. They thus proliferate for several cycles and make it possible to produce much more neurons. “
You have 46.49% of this article to read. The continuation is reserved for subscribers.