Scientists claimed to have discovered the first case of Down syndrome in Neanderthals, suggesting that archaic humans were compassionate caregivers.
The team analyzed a small skull fragment from a six-year-old girl they named ‘Tina’ who lived more than 1,450,000 years ago and found that the fossil had characteristics consistent with children with this genetic disorder.
The analysis showed that Tina He suffered from a congenital pathology in the inner ear that is related to the genetic disorder and probably caused severe hearing loss and disabling vertigo.
The discovery has suggested that Neanderthals were capable of providing altruistic care and support to a vulnerable member of their social group, as the child survived years after birth.
The team made digital scans of a small cranial fragment of a six-year-old girl they named ‘Tina’, which was discovered in Cova Negra, a cave in Spain.
Dr Mercedes Conde-Valverde, professor at the University of Alcalá and lead author of the study, told DailyMail.com: ‘Until now, it was only possible to diagnose Down syndrome in fossil specimens through ancient DNA analysis.
‘In our work we have been able to diagnose it through an anatomical study of the inner ear.
“This opens the possibility of studying the possible presence of Down syndrome in fossil specimens and thus being able to document its prevalence in past populations.”
The fossils were found in the Cova Negra, a cave located in Valencia, which was excavated between 1929 and 2017.
Researchers recently analyzed remains found during a 1989 excavation and discovered three new fossils that had previously gone unnoticed.
While the age cannot be determined, the team believes they are between 146,000 and 273,000 years old, depending on when the region was inhabited by the now-extinct species.
Among the trio was “an immature temporal bone (CN-46700),” the team wrote in the study published in Scientific advances.
It was a fragment of one of the two temporal bones – the right one – that help form the sides and base of the skull, protecting the brain and surrounding the ear canal.
The researchers used microcomputed tomography on the fossil, a 3D imaging technique that uses X-rays to view the inside of an object, slice by slice.
Digital examination of CN-46700 showed a combination of inner ear abnormalities consistent with Down syndrome.
“The pathology suffered by this individual caused highly disabling symptoms, including, at a minimum, total deafness, severe attacks of vertigo and inability to maintain balance,” said Dr. Conde-Valverde.
The digital scan of CN-46700 showed an abnormally reduced volume in the cochlea, compared to the fossil of Kebara 1, a Neanderthal without the abnormalities.
“Taking these symptoms into account, it is highly unlikely that the mother alone would have been able to provide all the necessary care and at the same time attend to her own needs,” Conde-Valverde added.
Therefore, for Tina to have survived at least six years, the group must have continually helped the mother, either taking over the care of the child, helping her with her daily tasks, or both.’
CN-46700 showed abnormally reduced volume in the cochlea, a hollow tube in the inner ear that looks like a rolled-up snail shell and contains the sensory organ of hearing.
This suggested that the cavity was much narrower than average, which is found in up to 50 percent of children with Down syndrome.
The scan was compared to another digital Neanderthal ear from a child of about the same age, showing a difference from Tina’s.
Other symptoms experienced by CN-46700 “would have included, at a minimum, severe hearing loss and a markedly reduced sense of balance,” Conde-Valverde and his team wrote.
The researchers also identified a malformation in the lateral semicircular canal, which previous research had considered common in people with Down syndrome.
The lateral semicircular canal is the shortest of the three auditory canals and detects angular and rotational movements of the head.
The discovery, according to the researchers, has suggested that Neanderthals were capable of providing altruistic care and support to a vulnerable member of their social group as the child survived years after its birth.
A 2014 study by the University of Montreal, which analyzed 34 years of subjects with Down syndrome, found that 5.8 percent had two cases of lateral semicircular canal malformation.
The fossilized ear canal also showed enlarged vestibular aqueducts, previously detected in individuals with this genetic condition.
The team noted that when the fossils were found in 1929, the average life expectancy of a child with Down syndrome was only nine years.
And previous research found earlier cases during the Iron Age, but the three known examples did not survive more than 16 months.
The fact that Tina lived to be six years old suggested that other members of her group cared for her.
Previous evidence that Neanderthals cared for the sick and injured sparked debate about whether this was motivated simply by expectations of reciprocal behavior or by genuine compassion.
“For decades, Neanderthals were known to care for and care for their vulnerable companions,” Conde-Valverde said.
Temporal bone fossil CN-46700 is shown in the photo. The left shows the posterior view, the middle image is the medial view, and the right shows the anterior view.
‘However, all known cases of caregiving involved adult individuals, leading some scientists to believe that this behavior was not true altruism but simply an exchange of help between equals: ‘Today for you, tomorrow for me.
‘What was not known until now was the case of a person who had received extra-maternal care since birth, although he could not reciprocate.
“The discovery of the Cova Negra fossil supports the existence of true altruism among Neanderthals.”
Archaeological evidence at Cova Negra has indicated that the site was occupied for short periods by small groups of Neanderthals, hunter-gatherers who roamed the landscape in search of food and other resources.
Tina’s age at death, based on the state of maturation of certain inner ear structures, showed unusual longevity for a child in such circumstances with a condition known for intellectual disability and developmental delays.
“The survival of this child, beyond the breastfeeding period, implies group care, probably longer than parental care, typical of a highly collaborative social context among group members,” says co-author Valentín Villaverde, a university student at the University of Valencia. Emeritus Professor of Prehistory.
“Otherwise, it is very difficult to explain the survival of this individual until he was six years old.”
“Tina’s discovery,” said Conde-Valverde, “represents the oldest known case of Down syndrome and demonstrates that the diversity observed in modern humans was already present in prehistoric times. This finding guarantees that the history of human evolution includes all of us.’
