Revealed: how ancient Ireland’s ruling classes were an inbred lot
ANCIENT DNA has revealed inbreeding among the dynastic elite of Neolithic Ireland.
The finding centres around the remains of an adult male found at the 5,000-year-old passage tomb at Newgrange in Co Meath.
A study, led by Trinity College Dublin and published in Nature, uses genetic sequencing to reveal the man’s relatives were buried in other passage tombs more than 100km away — the cemeteries of Carrowmore and Carrowkeel in Co Sligo, and the Millin Bay monument in Co Down.
It points to a powerful social elite at the top of Irish Neolithic society.
Older than the pyramids, the Unesco World Heritage site at Newgrange is renowned for its annual solar alignment. However, little is known about who was interred in the heart of the monument or of the Neolithic society which built it over five millennia ago.
The man was buried within the most ornate chamber in the tomb, with specialised ritual inventory, and winter solstice solar alignment that would have been viewed only by a select few.
Professor Dan Bradley, of Trinity College Dublin, said: “The prestige of the burial makes this very likely a socially sanctioned union, and speaks of a hierarchy so extreme that the only partners worthy of the elite were family members.”
The research was carried out in collaboration with colleagues from Queen’s University Belfast, University College London, NUI Galway, University College Cork, University of Cambridge, Sligo Institute of Technology and the National Monuments Service, with support from the National Museum of Ireland and National Museums Northern Ireland.
Prof Eileen Murphy from Queen’s University said: “It is quite incredible to think that the man born of an incestuous union and interred inside the Newgrange passage tomb was biologically related to those buried in tombs in the megalithic cemeteries in Sligo and the Millin Bay monument in Co Down.
“These burial clusters lie several hundred miles apart from one another and are suggestive of widespread and enduring connections.”
This study has confirmed these connections through ancient DNA.
The researchers sequenced 44 whole genomes from Irish Neolithic people, alongside relevant ancient genomes.
These were merged with an ancient dataset to allow for more detailed analysis of population structure and estimation of inbreeding.
Overall, the researchers observed no increase in inbreeding during the Neolithic period in Ireland, indicating that communities maintained sufficient size and communication to avoid mating with fifth-degree relatives or closer.
Dr Thomas Kador from UCL said the new evidence matched up with tales from mythology.
“In Irish mythology there is a tradition associating the tombs of the Boyne Valley with incestuous relationships among ancient royals and deities, and it is striking how these stories resonate with our findings,” he said.
“Irish folklore and literary scholars have long suggested that these stories, first recorded in the Middle Ages, date back to a long-standing oral tradition.
“However, nobody would have assumed that such traditions could stretch back to the Stone Age.”
The Millin Bay megalithic site in Co Down has always been considered somewhat atypical because its shape does not conform to that of the main megalithic monument classes.
It has previously been considered, however, to have passage tomb affinities because of its association with megalithic art and Carrowkeel pottery typical of these burial grounds.