San Diego, California, USA: Geneticist Alysson Muotri of the University of California, San Diego, led a group of scientists who combined the study of ancient DNA, the editing of genomes with CRISPR, and building “organoids” from stem cells to create what they call “Neanderoids.” The researches swapped one protein-coding gene from the Neanderthal genome into human stem cells that grew into pea-sized masses resembling the cortex, or outer layer of the brain. When compared to brain organoids made with only modern human DNA, the neuronal cells in the Neanderoids migrate more quickly as they form structures, the Neanderoid neurons appear to have an abnormal neuronal network, and the individual Neanderoids appear have a “popcorn” shape, while the modern human brain organoids are spherical. Muotri says similar changes in neuronal development have been observed in the brains of children with autism, hinting they could be linked to socialization abilities. “If we believe that’s one of our advantages over Neanderthals,” he said, “it’s relevant.”
The results of this unprecedented experiment were presented at June’s UCSD conference called ‘Imagination and Human Evolution.’
According to Muotri, his team has infused human stem cells with Neanderthal DNA that they extracted from the fossilized remains to artificially grow mini brains that mimic the cerebral cortex, the outer layer of real brains.
According to Professor Muotri, the brain activity of these tiny so-called organoids should be similar to that in our brains and should give us some idea about the core differences between human and Neanderthal brain and how they process information and feelings.
There is at least one more team working to create Neanderthal ‘mini-brains,’ this one at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
The Institute’s director, Professor Svante Paabo, says we’re way off from resurrecting an actual living Neanderthal, but the mini-brains could unlock a lot of mysteries.
What the scientists are hoping to understand is how the long-extinct creatures planned, socialized and used language.
But according to Professor Pääbo, it is nearly impossible to state with any degree of certainty that the organoids will be able “to tell us how adult brains function.”
Muotri’s team has so far revealed that neurons in the so-called ‘Neanderoids’ make fewer synaptic connections, creating what resembles an abnormal neuronal network in the brains of children with autism. The geneticist is very cautious about any statements, saying that he wouldn’t want families to jump to conclusions thinking his team is comparing autistic kids to Neanderthals. “But it’s an important observation,” he says.
Muotri has already developed human organoids and is working to hook them to little robots and have them control their functions. He hopes that the next step would be pitting those robots against Neanderthal-brain-controlled ones.
“The complexity of the human brain, with thousands of neuronal types, permits the development of sophisticated behavioral repertoires, such as language, tool use, self-awareness, symbolic thought, cultural learning and consciousness in a short period of evolutionary time. Understanding what produces such complex network system during brain development has been a longstanding challenge for neuroscientists and may bring insights into the evolution of human cognition. Human pluripotent stem cells have the ability to differentiate in specialized in different cell types and tissues. From these pluripotent state, it is possible to generate organoid models, simplified representations of the human brain. We have been using brain-model technology (BMT) combined with genome editing to gain insights on several biological processes, such as human neurodevelopment and evolution. The reconstruction of human network activity evolving in a dish can help to understand how neural network oscillations might contribute to human imagination. Our findings suggest a potential bridge to the gap between the microscale in vitro neural networks electrophysiology and the live human brain.” the researchers wrote.