Neanderthal DNA conjugated to “mini brain” provides clues about human evolution: Shot

Alysson Muotri, a scientist at the University of California, San Diego, has grown brain organoids from human stem cells that have exchanged Neanderthal developmental genes for human versions.

Muotri Lab / UC San Diego

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Muotri Lab / UC San Diego

Alysson Muotri, a scientist at the University of California, San Diego, has grown brain organoids from human stem cells that have exchanged Neanderthal developmental genes for human versions.

Muotri Lab / UC San Diego

Fossils provide a detailed record of the early human skull, but the brain in it does not.

That’s why researchers have used genetic material from these fossils to find clues about how the human brain has evolved over hundreds of thousands of years.

And now they have succeeded in growing a human brain organoid or “mini brain” that contains a Neanderthal variant of the gene called NOVA1 from the team. Report In the journal Science..

“Old-fashioned versions of genes change the shape of these organoids,” he says. Allison Muotri, Professor of the University of California, San Diego and the Sanford Regenerative Medicine Consortium. He says that Neanderthal organoids have a non-uniform outer layer instead of growing into smooth spheres on the surface.

Organoids with the ancient NOVA1 gene also appear to mature faster and remain smaller than modern organoids, says Muotri. “Neurons start to become more active very early on,” he says.

The findings are consistent with the hypothesis that modern humans have evolved a large brain that continues to develop throughout life to navigate complex social systems.

The rapidly maturing brain is more capable at birth. However, it is unlikely that modern humans will continue to develop during childhood, the time to acquire important social skills.

Muotri and a large team chose NOVA1 because it is one of a relatively small gene group that has changed significantly from Neanderthals. Denisovan I walked around the earth. It is also a gene known to play an important role in brain development.

Compared to brain organoids grown from normal human cells (left), organoids with Neanderthal gene variants (right) have a coarse outer layer.

Muotri Lab / UC San Diego

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Muotri Lab / UC San Diego

Therefore, NOVA1 provided a “perfect” way to see if ancient genes could alter the way the brain develops, Muotri says.

To investigate, Muotri and his team turned to brain organoids, a small cluster of human brain tissue that grows in the laboratory and mimics early brain development. However, Muotri says that existing organoids had only the latest version of the NOVA1 gene.

“So we replace the old-fashioned version with the modern version,” he says, using common gene editing techniques. Scientists then saw how brain organoids, including archaic versions, differ.

Muotri says there is probably a reason why humans with newer variants of NOVA1 survived, but humans with older versions died.

“In the process of evolution, we may suggest that we have acquired the mutation. [did] Bring us [a] The big advantage of having this complex brain in later years, “he says.

The idea has been endorsed by scientists studying the effects of Neanderthal genes that are still present in many humans, especially those of European and East Asian ancestry.

“It’s very exciting to be able to actually explore who we are and what we are, using our knowledge of archaic DNA,” he said. Dr. Karen Berman, Head of Clinical and Translation Neuroscience Division, National Institute of Mental Health.

Herself the study People with high levels of Neanderthal genetics have shown that they tend to resemble Neanderthal skulls.

Berman and her colleagues evidence Neanderthal genes supported the creation of brain networks that focus on visual and spatial abilities rather than social interactions.

“It may have been the lack of these social networks that led to the death of the Neanderthals,” says Berman.

Dr. Michael Gregory, a psychiatrist and scientist working with Berman, says it’s easy to imagine how the Neanderthal brain became obsolete.

“If they went looking for food or hunting, they could better find traffic to different places,” he says. “But they also couldn’t form a group to fight common predators.”

And the cooperation of the group was important for the success of modern people.

Gregory says that all research on the ancient brain goes far beyond human history.

“What drives us is not only how things happened over time and in the process of evolution, but also how things went wrong and caused neuropsychiatric illness.

Gregory says that if scientists can answer these questions, they may be able to develop better treatments for disorders such as schizophrenia and autism.