A genetic mystery surrounding red blood cells might have played a role in the demise of our Neanderthal relatives, according to a new study, but the full story is far from simple.
A deadly genetic mismatch
The research suggests a fatal genetic incompatibility between Neanderthals and modern humans, which could have contributed to the extinction of our ancient cousins. Here's the twist: it's all linked to a gene that affects red blood cell function.
When Neanderthals and early modern humans encountered each other in Eurasia approximately 45,000 years ago, they didn't just exchange genes; they also potentially passed on hidden reproductive risks. Patrick Eppenberger and his team discovered that different versions of the PIEZO1 gene, which is found in both modern humans and Neanderthals, may have caused hybrid Neanderthal-human women to miscarry.
Oxygen's double-edged role
The Neanderthal variant of PIEZO1 allowed hemoglobin to cling tightly to oxygen molecules, possibly an adaptation to survive extreme cold and starvation. But this very adaptation could have been detrimental during pregnancy. High oxygen levels in maternal blood can lead to low oxygen supply to the fetus, causing growth restrictions or even miscarriage.
A complex inheritance
The genetic incompatibility only arises in specific mating scenarios, such as a hybrid Neanderthal-human mother with a modern human father. This would have significantly reduced the chances of offspring survival, impacting the ability of Neanderthal women to pass on their mitochondrial DNA to future generations.
Unraveling the puzzle
Paleolithic archaeologist April Nowell highlights the study's significance in understanding Neanderthal extinction, particularly the maternal-fetal incompatibility in oxygen transfer. John Hawks, a biological anthropologist, draws parallels to other genetic blood conditions in modern humans, suggesting that the Neanderthal gene variant's negative effects may have led to its decline in modern populations.
But the PIEZO1 gene is just one piece of the complex puzzle of Neanderthal extinction. Eppenberger and his colleagues emphasize that the impact of interbreeding was likely subtle and gradual, and more research is required to uncover other potential hybrid incompatibilities.
And this is the part most people miss: could this genetic incompatibility be a key factor in the Neanderthals' fate, or is it just one of many influences? The debate continues, and the full story of our ancient cousins' disappearance remains a captivating mystery.
