Ancient DNA analysis has revealed a detailed picture of the life of a toddler who died in southern Italy 17,000 years ago, possibly due to a congenital heart condition.
In 1998, researchers discovered carefully laid under rock slabs in the floor of the Grotta delle Mura cavern in Apulia, southern Italy. It was the only burial in the cave, which also included signs of daily life and human occupation, says at the University of Florence in Italy.
Recently, Modi teamed up with multiple specialised teams across Italy and Germany to carry out modern analytical techniques on the remains of the little boy, who died when he was about 16-and-a-half months old, at about 82 centimetres tall.
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Radiocarbon dating placed the skeleton at between 17,320 and 16,910 years old – when Earth’s climate was beginning to warm up after the coldest part of the last glacial period.
Most ancient skeletons in warm climates like southern Italy become too degraded for significant DNA analysis, says Modi. But the child’s bones were well preserved in the cave’s cold conditions, allowing the researchers to recover about 75 per cent of the baby’s genome – “a remarkable achievement for ancient remains of this age”, she says.
“This enabled us to make robust conclusions about the infant’s ancestry, physical characteristics and even certain health aspects,” says Modi.
The child’s skin was darker than most modern Europeans, but not as dark as people from tropical climates, she says. He had blue eyes, in keeping with other recent discoveries . “This challenges modern assumptions about the appearance of ancient populations,” says Modi.
The genome also showed that the child had familial hypertrophic cardiomyopathy, a hereditary condition that causes thickening of the heart muscle and can lead to congestive heart failure and death, even in young people. His parents were closely related – probably first cousins.
Like most ancient hunter-gatherers, the baby carried genes for lactose intolerance – which only started to become less common with the advent of agriculture and animal domestication in northern Europe, says Modi.
As for the child’s teeth, the incisor and molar selected for analysis showed lines that reflect health challenges before and after birth, says team member at the University of Bologna in Italy. Those could have been due to the baby’s heart condition, but it is also possible that the mother struggled to get good enough nutrition during pregnancy. In addition, a fracture in the baby’s collar bone hints that he might have had a difficult birth.
Isotopes in the child’s teeth suggest that – unlike many hunter-gatherers – his mother stayed in one area during pregnancy, says Higgins. That might reflect her group’s way of life.
“We imagine that the mother lived in a close-knit community,” says Higgins. “Her life may have involved gathering food and taking part in other daily activities, remaining rooted in the local environment.”
This wouldn’t be a surprise, says at the University of Otago in New Zealand. “Mobility of human groups is often dictated by the availability of foods, and there is no reason to suggest that the region couldn’t have sustained them year round,” she says.
On a broader scale, the child’s genome reveals genetic traits from different hunter-gatherer groups based in other parts of Europe, suggesting group movements that started earlier than previously thought, says at Max Planck Institute for Evolutionary Anthropology in Germany, who didn’t participate in the research.
“The Mura child already exhibits the genetic ancestry that would become widespread in Italy around 14,000 years ago,” she says. “However, it pushes back the presence of this ancestry to around 17,000 years ago, which approximately corresponds to the end of the glacial period.
“We are increasingly learning more about Ice Age populations, and this study adds a valuable piece to the puzzle.”
Nature Communications
