40,000 years ago, the last Neanderthal hominids went extinct, leaving modern humans – Homo sapiens – to survive and thrive. We don’t know why the Neanderthals died off and why we endured, but scientists are hoping to know more by conducting a strange and creative lab experiment. They are literally growing tiny brains in a lab.
To create what the lead researcher calls “Neanderoids,” the scientists begin with skin cells from what’s known as a “neurotypical” person. This means they don’t have any known genetic defects associated with the brain. The researcher – Allyson Muotri – and his team focused on just one out of 200 protein-coding genes for their experiment. The NOVA1 gene appears most prominently during early brain development of modern humans and was responsible for probably more than 100 brain proteins in Neanderthals.
Neanderthals were very much like humans, but they went extinct. Could their brains tell us why?
Using the groundbreaking CRISPR technology, the scientists switched out the modern human NOVA1 for the Neanderthal version. We know what Neanderthal DNA looks like because we have samples from fossilized bones. The transformation of the stem cells into brain organoids takes between six to eight months. The result: a mass of cells that imitate the cortex, which is the outer layer of the brain. The Neanderoids are about the size of a pea.
Scientists have already created mini versions of the modern human brain, so now it’s possible to compare the two. Already, we know that the Neanderoids are shaped a bit like a popcorn kernel, while human mini brains are spheres. Scientists also learned that the neuronal cells containing Neanderthal NOVA1 move more quickly when creating structures, but they don’t know what this means. Other features may shed more light on how the Neanderthals socialized. The process isn’t perfect, however, and it’s possible for the mini brains to develop mutations.
These experiments could help answer questions about Neanderthal and human brains
What’s next? Muotri hopes to wire human mini brains and Neanderoids to crab-like robots, so he can see if the brains will learn to control the robot. It will give us a better idea of how the brains’ differences play out and potentially set up one of the coolest and most adorable robot fights ever.