Startling evidence has appeared concerning the identity of the people who developed a major culture known as the Atlantic Façade which spread megalithic monument-building all along the Atlantic and North Sea coasts of Europe. It seems these people did not originate in Europe at all, but were sophisticated Neolithic seafarers from the Near- or Middle-East, and while they interbred with many Mesolithic hunter-gatherers during their colonisation of the various regions they travelled through, once they arrived in Ireland and Britain the DNA of native hunter-gatherers of these islands completely disappeared.
An Introduction.
A new study in Nature, published in April 2019, explains how the farmers and builders of the Atlantic Façade coastal areas were a genetically separate group from the Neolithic peoples who had introduced farming into central Europe via the Balkans. Although both groups had their origins in the Middle-East, the builders of the Atlantic Façade had developed technical seafaring expertise that enabled them to establish a sophisticated and extensive culture of monument-building along the coastal fringes of southern and western Europe as they spread from their ancestral homes in the Fertile Crescent of the middle East. They took a maritime route along the southern coasts of the Mediterranean and up the Atlantic coast from Portugal to Brittany before establishing themselves in Britain and Ireland, but then the DNA of the original Mesolithic inhabitants of these islands disappeared, leaving little or no genetic trace in subsequent generations.
This new area of study, known as archaeogenetics, has provided information that sometimes confirms previous theories regarding migration patterns and culture spread, but it has also challenged other well-established hypotheses, causing fascination but also some consternation within the archaeological community regarding the ‘migrationist vs. diffusionist’ question, which has attempted to map the spread of new cultures in pre-history through the evolution or replacement of archaeological styles. Early theories favoured hoards of warriors sweeping across new regions and slaughtering all they found, a theory that fell out of fashion as it became clear that some novel techniques and styles seemed to have been spread by more peaceful means such as trade or intermarriage between neighbouring populations.
But a series of new studies suggests that, in ancient Britain and Ireland at least, the old-fashioned scenario of total population replacement may not have been far from the truth! It appears that the native British/Irish genome may have been almost totally replaced on a number of occasions between the appearance of hunter gatherers after the last ice age and the establishment of the Iron-Age Celtic tribes. In fact, it now appears that after Ireland and Britain became geographically detached from the European mainland, the islands became almost exclusively inhabited by immigrants whose ancestry originated from as far away as the Russian Steppe and the Middle East, and it was these immigrants who constructed some of Britain's and Ireland's most iconic monuments.
References
Brace S., Diekmann Y., Booth T.J. Ancient genomes indicate population replacement in Early Neolithic Britain. https://www.nature.com/articles/s41559-019-0871-9 Published: 15 April 2019
Paulsson, B. Schulz. Radiocarbon dates and Bayesian modeling support maritime diffusion model for megaliths in Europe (February 26, 2019). NAS. 116 (9): 3460-3465. doi:10.1073/pnas.1813268116
Callaway, E. Divided by DNA: The uneasy relationship between archaeology and ancient genomics Nature 555, 573-576 (2018) doi: 10.1038/d41586-018-03773-6
Olalde, I. et al. The Beaker Phenomenon And The Genomic Transformation Of Northwest Europe. Nature 555, 190–196 (2018).
Lazaridis et al., The genetic structure of the world's first farmers. bioRxiv preprint, posted June 16, 2016, doi: http://dx.doi.org/10.1101/059311
See also:
Mesolithic Britain and Ireland
The Atlantic Façade comes to Britain and Ireland
Bronze Age Beaker-Folk come to Britain and Ireland