Interbreeding With Neanderthals May Explain Risk For Fatal Neurological Condition In Modern Humans

The study, published this week in nan journal Evolution, Medicine, and Public Health, was led by Kimberly Plomp, a caller postdoctoral chap astatine SFU and Mark Collard, nan Canada Research Chair successful Human Evolutionary Studies and a professor successful nan Department of Archaeology.

Their findings propose that Chiari Malformation Type 1, a superior and sometimes fatal neurological condition, whitethorn beryllium linked to Neanderthal genes that entered nan quality cistron excavation done interbreeding tens of thousands of years ago.

Chiari Malformation Type 1 occurs erstwhile nan backmost of a human's skull is excessively mini to decently clasp nan brain, causing portion of nan guidelines of nan encephalon to herniate retired of nan skull and into nan spinal canal. This tin origin nan herniated portion of nan encephalon to beryllium pinched, starring to symptoms specified arsenic headaches, cervix pain, dizziness and, successful terrible cases, decease if excessively overmuch of nan encephalon herniates out.

The knowledge that our ancient quality ancestors successfully mated pinch Neanderthals (and immoderate different hominin species) is not new. The impacts of specified interbreeding, however, are still coming to light.

In 2010, scientists discovered familial grounds that members of our type interbred pinch Neanderthals tens of thousands of years ago. It is now clear that surviving non-Africans person 2 to 5 per cent Neanderthal DNA that tin beryllium traced to these interbreeding events. We person besides learned that genes from different extinct hominin type beryllium successful nan modern quality cistron excavation owed to interbreeding successful nan distant past.

The thought that Chiari Malformation Type 1 mightiness beryllium nan consequence of different hominin genes entering nan quality cistron excavation done interbreeding was initially projected by Yvens Barbosa Fernandes of Brazil's State University of Campinas.

Because nan modern quality skull differs successful respective important ways from those of different hominins, Fernandes reasoned, having a skull that is influenced by nan genes of different hominin type whitethorn beryllium 1 of nan factors that causes nan malformation.

Plomp, Collard, and their colleagues put this mentation to trial utilizing modern aesculapian imaging exertion and precocious statistical style study techniques to comparison 3D models of skulls from surviving humans, some pinch and without Chiari Malformation Type 1, to fossils hominins, including ancient Homo sapiens, Neanderthals, Homo heidelbergensis, and Homo erectus. 

The squad recovered that group pinch Chiari malformation stock much style traits successful communal pinch Neanderthals than do group without nan malformation. Interestingly, each different fossil skulls were person successful style to humans without Chiari Malformation Type 1, indicating that nan findings are not owed to shared ancestry, but alternatively support nan presumption that immoderate group coming person Neanderthal genes that impact their skull shape, and this skull style results successful a mismatch betwixt nan style of nan skull and style of nan modern quality brain.

It's this mismatch that results successful nan encephalon not having capable room successful nan skull, and thus, nan encephalon is pushed retired nan only spread available, nan spinal canal.

With different populations astir nan world having varying levels of Neanderthal DNA, nan study predicts that definite populations - including those from Europe and Asia - could beryllium astatine a higher consequence of Chiari Malformation Type 1 than others, though further investigation is required to corroborate this.

"Studying archaeology and quality improvement is not conscionable interesting. It besides has nan imaginable to thief america understand and, successful immoderate cases, header pinch problems successful nan present," says Collard. "In this case, we've utilized fossils to thief america shed ray connected a aesculapian condition, but location are a batch of different modern problems that archaeological and palaeontological information tin thief america understand better."

The squad included researchers from University of Manchester, Liverpool John Moores University, Manchester Centre for Clinical Neurosciences, and University of Sussex.

Source:

Journal reference:

Plomp, K., et al. (2025). A trial of nan Archaic Homo Introgression Hypothesis for nan Chiari malformation type I. Evolution, Medicine, and Public Health. doi.org/10.1093/emph/eoaf009.