In honor of Irish American Heritage Month, we’ve added a new group to our Historical MatchesSM feature that offers a glimpse into Ireland’s ancient past. This group, called the “Megalithic Society of Neolithic Ireland,” includes members of an elite society connected to Ireland’s megalithic tombs, which were built over 5,000 years ago.
What do we know about the ancient farmers who built Ireland’s megalithic structures?
The Neolithic Period (7000–2000 BCE) was a time of profound transformation in Europe, as populations transitioned from a nomadic hunter-gatherer lifestyle to settled farming communities. This era also saw the rise of megalithic architecture—monumental stone structures such as stone circles, dolmens, and passage tombs—built for both ceremonial and funerary purposes.
In Ireland, megalithic architecture first appeared around 4000 BCE, marking the beginning of a tradition that would shape the island’s landscape for millennia. While the enduring stone structures provide valuable insight into Neolithic craftsmanship and ritual practices, little was known about the ancestry, social organization, and kinship patterns of the people who built and used them—until now.
In 2020, researchers sequenced the genomes of 44 ancient individuals from sites across Ireland to better understand these early communities. What they discovered was unexpected.
The surprising case of inbreeding among Ireland’s ancient elite
One of the most remarkable individuals in this study was a man buried inside Newgrange, one of Ireland’s most famous and elaborate passage tombs. Built around 3200 BCE, Newgrange consists of a massive circular mound surrounded by a stone ring. A narrow passageway leads to a cross-shaped inner chamber, which aligns with the rising sun during the Winter Solstice, flooding the tomb with light in a dramatic annual event—suggesting it had deep ceremonial significance.
When researchers analyzed this man’s genome, they found something highly unusual: extreme genetic similarity between the DNA he inherited from his mother and father—a telltale sign of close inbreeding. Their analysis indicated that his parents were either full siblings or a parent-child pair.
While such close inbreeding has been considered taboo in most societies, his elaborate burial suggests that his parentage was not only accepted but possibly even socially sanctioned. The researchers proposed that this could be an example of “royal” or “dynastic” incest, a rare practice historically used by ruling families—such as the Egyptian pharaohs—to maintain political power and prestige within a single bloodline.
Elite burials across Ireland hint at an ancient dynasty
Further evidence of his elite status came from genetic links to several other high-status individuals buried in major passage tombs, including Carrowmore and Carrowkeel, located nearly 100 miles west of Newgrange. These connections suggest that a powerful, interconnected elite class may have existed in Neolithic Ireland, with its members buried in monumental tombs across the island—perhaps forming an early ruling dynasty.
Learn More
Want to find out if you share a distant connection to this elite lineage of Neolithic Ireland or to the many other non-elite individuals in this group? Explore the Historical Matches feature, available to 23andMe+ Premium™ members, to see if your DNA links you to this ancient dynasty—or to hundreds of other historical individuals from the past.
