Neanderoids
Geneticists seek to grow miniature likenesses of Neanderthal brains
Geneticist Alisson Muotri from the School of Medicine at the University of California, San Diego, spoke about the ongoing experiments in his laboratory on growing mini-brains of Neanderthals from cell cultures. A report on this work was made at the Imagination and Human Evolution conference in San Diego, the website of the journal Science tells about its content. At the moment, these are not attempts to fully reproduce the Neanderthal brain tissue, the cells in the experiment have only one Neanderthal gene.
Previously, the only way to find out the structure of the Neanderthal brain was to study the endocrines – prints of furrows and convolutions of the brain on the inner surface of the skull. Now a fundamentally new method is proposed. It became possible thanks to progress in three areas: the isolation of ancient DNA, genome editing and the cultivation of "mini-organs". Primitive miniature analogues of real organs grown from cell cultures have become much more advanced in recent years. Scientists were able to obtain analogs of the heart, kidney, brain, stomach, lungs, retina, large and small intestines in laboratory conditions. They have groups of differentiated cells similar to those found in full-sized organs.
A group led by Muotri grew pea-sized structures from stem cells with modified DNA that matched the DNA of Neanderthals, which reproduced the tissue of the cerebral cortex. Compared with similar organoids containing the DNA of modern humans, "Neanderthal" mini-brains have differences in both the shape and structure of neural networks.
Now Muotri and his colleagues' research is focused on the NOVA1 gene, which plays a role in early brain development in modern humans, and is also associated with autism and schizophrenia. A similar Neanderthal gene differs from it only in one pair of nucleotide bases. Muotri and his collaborators take skin cells of a "neurotypical person" (that is, a person without any known genetic defects associated with neurological disorders), then these cells are converted into pluripotent stem cells. Using the CRISPR genome editing method, they make changes to the NOVA1 gene corresponding to the Neanderthal genome. In a few months, cortical brain organoids grow out of cells (the authors of the work called them neanderoids).
Comparing them with organoids grown under similar conditions with a normal genome (above), the researchers noticed that neural cells with the Neanderthal NOVA1 gene (below) migrate faster within the organoid. The external shape of the organoids is also different: the usual almost spherical, "Neanderthal" ones are similar to popcorn.
Some of the differences found coincide with the signs that Muotri had previously observed in the brains of children with autism. "I don't want families to come to the conclusion that I am comparing autistic children with Neanderthals, but this is an important observation," says Muotri. – In modern people, these types of changes are associated with abnormalities in the development of the brain, which turn out to be key for socialization. If we think this is one of our advantages over Neanderthals, it's important."
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