(CNN)Humans have unusually globular (or round) skulls and brains compared to our ancient ancestors -- including our closest extinct cousins the Neanderthals -- and a new study provides a possible explanation as to why.
Neanderthal genes could explain the shape of our skulls, study finds
For the first time, an interdisciplinary team of scientists have identified two genes that affect the shape of the modern human's skull -- and they originate from Neanderthals.
"Billions of people living today carry a small fraction of Neanderthal genes in their genome -- a distant echo of admixture when our ancestors left Africa and encountered Neanderthals," said study author Philipp Gunz, a paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, via email.
These are typically humans with European ancestry stemming from interbreeding between Neanderthals and modern Europeans.
"By combining data from fossils, genetics and brain imaging we can learn something about evolutionary changes to brain development in our own species," said Gunz.
The team used MRI scans to analyze the cranial shape of about 4,500 peoples' brains before looking at their genomes to work out which fragments of Neanderthal DNA they carried.