December 3, 2022
Some people still have a copy of the Neanderthal gene, but the result is still a mystery

Some people still have a copy of the Neanderthal gene, but the result is still a mystery

Research by scientists at the Max Planck Institute for Cell Biology and Molecular Genetics in Dresden, Germany, has found that a mutation in the TKTL1 gene may have given modern humans a cognitive advantage over Neanderthals.

Through laboratory experiments, the team realized that a change in this gene, which is involved in regulating the growth of neurons in the cerebral cortex and which encodes a protein that is produced when the fetal brain is developing, significantly increases the number of neurons in the cerebral cortex. Hominins predated modern humans, giving them cognitive superiority over Neanderthals as well as other non-human primates.

Extinct human species neanderthal man They had larger brains than modern humans, but they were always associated with lower intelligence (although there are studies which shows that Neanderthals were more intelligent than initially thought). However, the study authors have also identified the Neanderthal version of TKTL1 in some modern humans, although they say it is very rare and still cannot answer some questions, such as whether it causes any disease or cognitive problems.

Studies published in 2014 that sequenced the genome of Neanderthals concluded that DNA of this type was not evenly distributed within the modern human genome. In one such investigation, nearly 100 different amino acids were identified between Neanderthals and modern humans, and with this in mind, Anneline Pinson and her team attempted to understand the genetic changes that contributed to the advantage of modern humans over Neanderthals and others. hominids.

In the lab, researchers carried out the study published this month in the scientific journal Sciencesintroduced modern human or ancestral versions of TKTL1 into the brains of house mice and rodent embryos and found that the first copy of the gene increased a type of neuron-generating cell in a region of the brain, the neocortex, responsible for complex functions such as memory, language and cognition.

In addition, the team also analyzed two copies of the gene in brain tissue created from human stem cells, called organoids, and the conclusions were similar. “This shows us that while we don’t know how many neurons a Neanderthal brain has, we can assume that modern humans have a higher number of neurons in the frontal lobe of the brain, where TKTL1 activity is higher than that of Neanderthals,” explains Welland Huttner. , one of the study authors. However, the difference in neuronal production was more “dramatic” in animal experiments than in organoids.

Given this study, Alison Muotri, a neuroscientist at the University of California, San Diego, USA, who was not involved in the study, said it’s important to test the progenitor version of TKTL1 in more human cell lines. “This has only been done on one cell line, and since we have huge diversity with the organelles protocol in the brain, it would be ideal to repeat experiments with a second cell line,” he said.

Mootri also said that the original Neanderthal genome has been compared to the modern European genome, making it possible that humans in some parts of the world shared the Neanderthal version of TKTL1.