Bred Neanderthals and humans

For the first time, researchers are breeding Neanderthal mini-brains

It is undoubtedly one of the most exciting questions that anthropologists and their specialist colleagues have to answer: What was responsible for the fact that the Neanderthals became extinct around 30,000 years ago and that modern humans remained as the only representatives of the homo genus?

The publications on this topic have long been in the thousands. This is also due to the fact that all of the hypotheses made are difficult to test empirically. With the decoding of the Neanderthal genome in 2009 by researchers led by paleogenetics pioneer Svante Pääbo, hard facts were hoped for. Indeed, the Neanderthal DNA showed few, but significant, deviations from ours.

Presumption of higher intelligence

But can these differences in the genome explain our presumed intellectual superiority? In any case, it couldn't have been the size of the brain itself, because there was more space for gray cells in the skulls of our closest relatives than in ours. But since nothing of the brain mass itself has been preserved, researchers have so far only been able to study the cavities in the skull.

On the occasion of his most recent lecture in Vienna, Pääbo indicated, who won the Körber Prize on Thursday, a new way of discovering the differences in brain and brain development between Neanderthals and modern humans: by breeding Neanderthals mini-brains.

Combination of three new methods

That sounds spectacular - and it is, although these so-called organoids are only the size of a pinhead. This approach was made possible by the combination of three hot research fields: the analysis of old DNA, the CRISPR / Cas9 gene scissors and the breeding of mini-brains, which was invented at the IMBA in Vienna.

The science magazine Science recently reported online about promising progress in these experiments - and first, as yet unpublished interim results. Specifically, it is about the research of a team led by Allyson Muotri (University of California in San Diego), who succeeded in inserting the Neanderthal version of the NOVA1 gene into stem cells with pinpoint accuracy using CRISPR / Cas9.

Amazing mini-brain differences

These modified stem cells then grew into mini-brains - like their human counterparts with the normal NOVA1 gene - in order to replicate the cerebral cortex on a small scale. In fact, there were amazing differences: the Neanderthal brain cells migrated faster within the organoid and ultimately resembled small popcorns, while the human organoids formed spherical shapes.

And the Neanderthal organoids had distant similarities in their internal organization to the brains of people with neurological defects such as autism.

Frankenstein sends his regards

What Muotri is planning with the mini-brains sounds really crazy in comparison: He wants to connect the human organoids with robots that look like crabs and hopes that the mini-brains will learn to control the machines. If that works, he would like to have them fight against those controlled by Neanderthal mini-brains. (Klaus Taschwer, June 23, 2018)