Study Reveals Striking Differences Between Our Brains and Neanderthals

— Petr Student / Shutterstock.com

New research suggests that a mutation stimulating the growth of neurons in our neocortex may be responsible for our superior cognitive abilities compared to Neanderthals.

The TKTL1 protein

The mutation in question leads to a single amino acid change in a protein called TKTL1. Previous studies have shown that this mutation is present in almost everyone living todaybut not in older humans, such as Neanderthals and the Denisovansnor in other primates.

The TKTL1 protein is also known to be produced in progenitor cells that give rise to the neocortex (the outer layer of the brain involved in conscious thought and language). suggesting that she may have helped shape the brain modern humans, in particular by increasing the synthesis of certain membrane molecules necessary to increase the production of neurons in the frontal lobe.

In the context of work published in the journal Science, Anneline Pinson and her colleagues at the Max Planck Institute sought to precisely determine its impact, by injecting the modern human TKTL1 protein into the brains of mouse and ferret embryos. They also cultured brain organoids from human cells, some of which were modified to produce the older version of TKTL1, present in Neanderthals.

Microscopic image of a dividing basal radial glial cell — © Pinson et al. / Science 2022 / MPI-CBG

These experiments showed that the mutation increased the number of neocortical progenitor cells, called radial basal glia, involving a higher number of neurons in this part of the brain. According to Wieland Huttner, co-author of the study, the result would have been ” an increase in the size of the neocortex, the density of neurons within it, or both “.

Similar sized but different shaped skulls

The study of the skulls suggests that the brains of modern humans and Neanderthals were similar in size, but different in shape, with Neanderthals having more elongated brains. According to the researchers, it is possible that this difference in shape is also due to the mutation.

Although we don’t know how many neurons there were in the Neanderthal brain, we can assume that the frontal lobe of modern humans, where TKTL1 activity is highest, harbors more. », points out Pinson.

So could we make people smarter by modifying genes to increase the number of basal radial glial cells? ” I don’t know if we could do it “says the researcher. ” Having more neurons can also have drawbacks. »

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