It is not the first time that tiny brains have been grown for research, but it is the first time that someone has grown a hybrid of the human organ with an ancient human cousin.
These sesame seed-sized brains created from a mix of human and Neanderthal genes briefly survived in Petri dishes in a laboratory at the University of California, San Diego.
Human mini-brains tend to be smooth spheres, like little marbles. Neanderthal brains were smaller and more irregular. Further analysis revealed that partially Neanderthal mini-brains were more chaotic in their neuronal activity and produced different sets of proteins than fully human ones .
The study offers clues about how organs have evolved over millennia. Some of the brains were grown using standard human genes, and others were altered using the CRISPR gene editing tool to obtain a brain development gene taken from Neanderthal remains.
Specifically, the researchers replaced the human NOVA1 gene in some of the stem cells used to grow mini brains with a NOVA1 gene reconstructed from genetic remains in the bones of long-dead Neanderthals. Researchers know that NOVA1 plays a role in brain development.
For now, researchers have taken the development of "mini-brains" to a point where they can detect electrical signals oscillating in tissues. According to Alysson Muotri , a geneticist at the University of California, San Diego, it is reminiscent of things found in the brains of people with autism:
I don’t want families to conclude that I am comparing autistic children to Neanderthals, but it is an important observation. In modern humans, these types of changes are linked to defects in brain development that are necessary for socialization. If we think this is one of our advantages over Neanderthals, this is relevant.