Mini Neanderthal brains grown in US lab

Scientists have successfully grown pea-size versions of Neanderthals' brains, an advance that may help better understand the species that went extinct about 40,000 years ago.

Cultivating and studying these mini brains may reveal why Neanderthals died out and Homo sapiens went on to conquer much of the planet, researchers said.

Genetic differences between Neanderthal and human brains may explain their demise and our success, said Alysson Muotri, director of the University of California, San Diego (UCSD) in the US.

It is possible that humans achieved great technological advancements because we have sophisticated neural networks, while Neanderthals didn't, Muotri said.

"Neanderthals are fascinating because they shared Earth with us, and there is now genetic evidence we actually bred with them," Muotri was quoted as saying by 'Live Science'.

Researchers compared the genome of Neanderthals with that of modern humans. Out of 200 candidate genes that showed significant differences between the two species, the researchers decided to focus one a gene expression regulator known as NOVA1.

NOVA1 is highly expressed during neurodevelopment and has been linked to neural conditions, such as autism and schizophrenia, Muotri said.

Scientists have already grown mini human organs, known as organoids, in the lab. To grow mini Neanderthal brains, they used the gene-editing tool known as CRISPR to "Neanderthalise" human pluripotent stem cells, or immature cells that can develop into any cell in the body, she said.

Then, using their in-house protocol, "we coaxed the stem cells to become a brain organoid," a process that takes between six and eight months, Muotri said.

Fully grown, the Neanderoids measure about 0.2 inches in size, "so you can actually see them with the naked eye once they are mature," he said.