Neanderthal blood may have extinguished them

When modern humans came out of Africa, a rapid evolution of their red blood cells may have helped them survive. In the opposite direction, it may have led to the eventual disappearance of the Neanderthals.

A study this Thursday in Scientific Reports revealed that the type of neanderthal blood can help explain your extinction.

By sequencing the genomes of dozens of people who lived between 120,000 and 20,000 years ago, the researchers found that the Neanderthals had a rare blood group that could have been fatal to their newborns.

As explained by the blood groups of humans are characterized by proteins and sugars – called antigens – Found on the surface of the red blood cells. An important antigen is the factor Rhwhich gives the “positive” and “negative” signs to blood types.

Since these variations in red blood cells are transmitted throughout generations, a team of researchers at the University of Aix-Marseille in France has decided to analyze the old genomes to better understand the evolutionary history of Neanderthals, Denisovans and Humans.

“Os Neanderthals have a blood group Rh that is very rare in modern humans, ”said the main author of the study, Stéphane Mazièresat Live Science.

This Rh variant – one type of RHD, another antigen of red blood cells – is incompatible with the variants that the team found in Denisovson or in the first Homo sapiens of your study.

“In any case of consanguineous crossing of a Neanderthal female with a Homo sapiens or denisova male, there is a high risk of hemolytic disease of the newborn,” explained the population geneticist. This disease can, finally, provoke Iteria, severe anemia, brain injuries and death.

“This may have contributed to the disappearance of the Neanderthal population”concluded the leader of the investigation.

The new study also found that the HR variants found in many people nowadays come from the first ancestors of Homo sapiens, who seem to have developed shortly after leaving Africa. Neanderthals, on the other hand, had HR variants compatible with each otherbut which remained virtually unchanged during the last 80,000 years of their existence.

Currently, the treatment of HR incompatibility involves prenatal administration of an immunoglobulin, a laboratory antibody that prevents pregnant women from producing antibodies against fetus blood. But 100,000 years ago, this type of red blood cell incompatibility would have been impossible to treat.

The lack of diversity in the red blood cells of Neanderthals and Denisovans may indicate consanguinity and decline in the number of inhabitantseventually leading to the extinction of these groups.

Although the general isolation of the Neanderthals can explain why their red blood cells have not evolved much over the years. However, there is still doubts about why the early red blood cells have diversified so much and so quickly – in a period of at least 15,000 years.