Rare Neanderthal DNA mean some people's brains are slightly different shape, study suggests

Interbreeding with Neanderthals thousands of years ago, elongated brains, according to a new study.

Scientists connected two ancient DNA fragments that have been passed on to European people with slight changes in skull and therefore brain shape.

A key feature of the human head is its distinct roundness, in contrast to extinct relatives and ancestors.

Due to some ancient humans breeding with Neanderthals, many Europeans alive today have up to 2 per cent Neanderthal DNA scattered around their genomes.

Previous research has suggested this genetic material may help fight off infections, but the next step is that some people still have Neanderthal-like heads.

Professor Simon Fisher, one of the scientists behind the work, said the effects of the DNA fragments were "really subtle", but they detected them across a large sample size of nearly 4,500 European MRI brain scans.

They then used information from previous Neanderthal DNA studies to identify pieces inside living human genes that were correlated with more elongated heads.

Both fragments contained genes already known to the brain development known as UBR4 and PHLPP1, which makes sense of the shape of the brain and are interlinked.

"We know that UBR4 or PHLPP1 disrupts UBR4 or PHLPP1 completely consequences for brain development," explained Dr Fisher, a geneticist at the Max Planck Institute for Psycholinguistics.

The Neanderthal fragments were discovered in key roles such as learning and coordinating movements.

However, the scientists are stressed there is no indication that the DNA pieces have any effect on the cognitive abilities of modern humans.

"The focus of our study is on understanding the unusual brain shape of modern humans," said Dr Philipp Gunz, another Max Planck Institute scientist.

"This could not be done."

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The researchers said they hope this discovery will help them unravel how modern humans first evolved their distinct brain shape.

They now intend to scale up their studies to include even larger samples, including a sizeable collection of genetic material from British people.

Ultimately they hope to find the full suite of genes controlling the shape of human brains, and how their roundness is linked to other characteristics.

These results were published in the journal Current Biology.

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