Online Science Editor Vincent Plant discusses how DNA evidence has transformed our understanding of Neolithic Ireland
If you travel to 25 kilometres north of Dublin, you may come across a vast stone circle known as Newgrange, built a thousand years before the pyramids of Giza. In the centre of the monument is the tomb of an individual who was buried there 5000 years ago in the Neolithic. This in itself is not that surprising; however, DNA evidence has now revealed the possibility of a structure that would have seemed familiar to later civilisations- a ruler who was considered divine.
DNA evidence has now revealed the possibility of… a ruler who was considered divine
The man buried at Newgrange appears to be middle aged and died sometime around 3200 BCE. His DNA was sequenced, along with 43 others from across Ireland, in an attempt to follow the slow expansion of settlers from Anatolia across Europe who arrived in Ireland in approximately 3700 BCE. What they found was surprising: his parents were first-degree relatives, meaning they were either siblings or parent and child.
In most cultures there is a heavy taboo associated with such unions, for interlinked biological and cultural reasons. However, there is somewhat of an exception to this rule whereby if they do occur, it is likely to be within royal families that were said to have some sort of divinity. Previous consensus had been that Neolithic Irish culture was reasonably egalitarian; houses were found to be roughly similar sizes and hierarchy is markedly absent from gravesites. The implied existence of such a ruling class seems to undermine this assumption.
Close relatives having children has been common in royal families throughout history, such as the Ptolemies of Egypt, the 13th century Sapa Inca known as Manco Cápac, and the Habsburgs, to name only a few. Tutankhamun’s parents were full siblings, Charles II of Spain had only a third of the normal number of ancestors. As may be expected, this causes health repercussions involving recessive conditions cropping up, and therefore parents are more likely to pass on the same alleles to their children.
Members of this ‘clan’ have been found all across Ireland, which led the main author of this study Dr Cassidy to suggest that the family had access to prime gravesites across Ireland for 500 years at least, and were prominent and powerful in society.
Members of this ‘clan’ have been found all across Ireland
The genetic study also revealed the oldest person to retroactively be diagnosed with Down’s syndrome, a condition resulting from three copies of chromosome 21. The boy was buried in a sacred place five and a half thousand years ago in county Clare, and was found to have been breastfed before his death.
Dr Cassidy felt that the study would allow an insight into the values of an ancient civilisation. DNA evidence can sometimes allow us to peel back the years in a way that other evidence cannot, showing how vital it will remain across disciplines in years to come.