Stem cells, the self-renewing precursors of other cell types, can be used to build brain organoids [or] “mini brains” in a laboratory dish. [Professor of medicine Alysson] Muotri and colleagues have pioneered the use of stem cells to compare humans to other primates, such as chimpanzees and bonobos, but until now a comparison with extinct species was not thought possible.
In a study published February 11, 2021 in Science, Muotri’s team cataloged the differences between the genomes of diverse modern human populations and the Neanderthals and Denisovans, who lived during the Pleistocene Epoch, approximately 2.6 million to 11,700 years ago. Mimicking an alteration they found in one gene, the researchers used stem cells to engineer “Neanderthal-ized” brain organoids.
It’s fascinating to see that a single base-pair alteration in human DNA can change how the brain is wired. We don’t know exactly how and when in our evolutionary history that change occurred. But it seems to be significant, and could help explain some of our modern capabilities in social behavior, language, adaptation, creativity and use of technology.
“This study focused on only one gene that differed between modern humans and our extinct relatives. Next we want to take a look at the other 60 genes, and what happens when each, or a combination of two or more, are altered,” Muotri said.