Ancient DNA from an Italian cave uncovers dark case of father/daughter incest

The DNA uncovered a complex ancient community with a startling family secret.

In a mountain cave in southern Italy, Bronze Age families buried their dead for centuries. Now, those scattered bones are telling a story of migration, dietary resilience, and one extraordinary family event.

At Grotta della Monaca, Calabria, researchers reconstructed the genetic and social life of a Protoapennine group that lived between about 1780 and 1380 BCE. By extracting ancient DNA from scattered bones, they traced family ties, long-distance connections, and daily habits. They also uncovered the earliest known clear genetic evidence of a father-daughter incest in prehistoric Europe, preserved in the genome of a teenage boy buried there.

The study was published this week in the journal Communications Biology.

Wider Connections

Grotta della Monaca lies more than 600 meters above sea level in the Pollino massif in southern Italy. It’s far from the Bronze Age towns and ports that usually dominate Mediterranean archaeology. Yet, the people buried there were not as isolated as you might think.

“Our analysis shows that the Grotta della Monaca population shared strong genetic affinities with Early Bronze Age groups from Sicily, yet lacked the eastern Mediterranean influences found among their Sicilian contemporaries,” said Francesco Fontani, the study’s lead author, in a statement.

The pattern suggests that Calabria followed a distinct demographic path, even while maintaining contact across the narrow Strait of Messina. Two individuals carried genetic links to northeastern Italy, evidence of long-distance travel across the peninsula.

The DNA showed a common Bronze Age pattern, combining ancestry from early farmers, European hunter-gatherers, and steppe herders. It closely matched Early Bronze Age Sicily, with some local differences. Despite living in a small mountain community, these people were part of wider patterns of movement and contact.

Food, Family, and Burial

The researchers also found that burial practices here were strictly organized. Mothers were laid to rest near their children, and one specific sector was devoted almost entirely to women and juveniles, with only a single adult man present.

But the bones reveal more than just who died; they reveal how they lived.

Genetic markers showed that most individuals in the cave were lactose intolerant. Biologically, they shouldn’t have been able to drink milk as adults without getting sick. Yet, isotopic evidence from their bones indicates they consumed significant amounts of dairy. But this didn’t stop them.

“This paradox illustrates how cultural adaptation can precede genetic evolution,” said Donata Luiselli, a co-senior author of the study, in a statement. Long before the genetic mutation that allows most adults today to digest milk became common in Europe, people were already herding animals and finding ways to use their products.

Long before the genetic mutation for lactase persistence became common in Europe, these herders had figured out a workaround—likely processing milk into cheese or yogurt to reduce the lactose, allowing them to survive in a rugged mountain environment.

A Dark Family Secret

Among the 23 individuals analyzed, one genome stood out immediately. A pre-adolescent boy showed an extreme amount of shared genetic material—far more than you see even in small, isolated populations.

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When the team looked closer, they found what they call “indisputable evidence” of a first-degree incest. The boy was the son of the only adult male buried in that main funerary area. The mother was that man’s own daughter.

“This exceptional case may indicate culturally specific behaviours in this small community, but its significance ultimately remains uncertain,” said Alissa Mittnik, a senior author of the study, in a statement.

While archaeologists have found evidence of incest before, it is usually between siblings and often in royal or elite contexts (think ancient Egypt or the Incas) to preserve a bloodline. Parent-child unions are much rarer and biologically riskier.

Why this happened remains unknown. The community was not extremely small, nor does it show evidence of rigid hierarchy. Whether the union was tolerated, coerced, or a singular transgression may never be clear.