Scientists have long suspected that inbreeding was one of the main causes that led to the extinction of Neanderthal man. And this seems to be confirmed by a recent study led by Spanish researcher Antonio Rosas, from the Higher Council for Scientific Research (CSIC), which has been published in Scientific Reports .
To carry out the research, Rosas and his team analyzed the fossil remains of the thirteen Neanderthals recovered in the Asturian cave of El Sidrón, all members of the same family. They detected seventeen congenital anomalies distributed throughout his skeleton: nose, jaw, ribs, feet, wrists… Everywhere they showed genetic singularities.
“The Neanderthals lived in small groups and geographically separated from each other, so they were practically isolated,” explains Rosas. The result is that they began to interbreed between members of the same family and, with the passage of time, in addition, the group was further reduced and inbreeding increased. This inbreeding, maintained over time, could lead to a significant decrease in Neanderthal biological variability ”.
The remains of the thirteen Neanderthals from El Sidrón correspond to seven adults –four women and three men–, three adolescents and three children. They all belonged to the same family. “At least four of the thirteen Neanderthals from El Sidrón had an anomaly in the closure of the anterior or posterior arch of the cervical vertebrae,” says another of the researchers, Luis Ríos, from the Paleoanthropology Group of the National Museum of Natural Sciences of the CSIC. Another striking case is the presence of congenital anomalies in the scaphoid (one of the bones of the wrist) ”.
“Studies carried out on various samples, including those from El Sidrón, indicate high levels of inbreeding, maintained over time, and with a possible increase in the last surviving Neanderthal groups ,” adds Ríos.
An old Asturian family
The remains discovered in the El Sidrón cave, in the Asturian town of Piloña, belong to Neanderthals who lived there about 49,000 years ago. This collection of remains, made up of more than 2,500 pieces, is the most complete and abundant in the Iberian Peninsula. Among the bone remains found, four jaws, three maxillae, a multitude of teeth, cranial fragments and bones of the trunk and extremities stand out.
The investigation of these remains has allowed many conclusions to be drawn about how these prehistoric communities lived. Thus, for example, evidence has been found that they divided work by sex, that they knew the medicinal use of certain plants, that their diet included pine nuts, mushrooms and mosses, and even that they practiced cannibalism.
Image: On the left, a Neanderthal skeleton with 11 of the physical anomalies detected. On the right, some of the bones analyzed for the study (MNCN-CSIC Comunicación Paleoanthropology Group).
