The Neanderthal, the other intelligent human species that disappeared approximately 40,000 years ago, still lives inside us. Between three and four percent of the genes of Homo sapiens are of Neanderthal origin. But there are many things we cannot know about Neanderthals by simply studying their fossilized remains, such as how their brain looked like. However, two groups of researchers went further and combined the high-end techniques of ancient DNA sequencing, the CRISPR genetic editing and the production of organoids (pseudo-organs grown from stem cells) to create Neanderthal mini-brains.
Early research, which has not yet been published in any studies, shows that these organoids have a different neuronal shape and connections than organoids built from Homo sapiens genes.
“We are trying to recreate the minds of Neanderthals,” explained Alysson Muotri, a geneticist at the University of California, San Diego, cited by Science Mag. His research group presented the preliminary results at a conference held at the university this month.
These researchers focused on one of the 200 known genes that differ between Neanderthals and modern humans, namely, the NOVA1, a central sequence in brain development and whose imbalances seem to be linked to the onset of autism and schizophrenia. This sequence is especially impressive because it only has a punctual difference between Neanderthals and modern-day humans.
Neanderthal mini-brains, created in the lab using ancient DNA, presented characteristics seen in modern humans with autism
Muotri has found that, unlike humans, Neanderthal mini-brains with the ancient DNA variant of NOVA1 are characterized by their cells migrating faster as their structures form.
“We think it’s related to the shape of the organoid, but we have no idea what it means,” the researcher admitted.
Also, Neanderthal mini-brains have an irregular, popcorn-like shape, while those of modern humans are somewhat spherical. Also, the neurons in the Neanderthals’ brains presented fewer synaptic connections, forming an abnormal network that, according to the researchers, resembles things found in the brains of people with autism.
“In modern humans, these kinds of changes are linked to defects in brain development that are necessary for socialization. If we believe that this is one of our advantages over the Neanderthals, it is a relevant observation,” explained Alysson Muotri.