It proposed that the Early Medieval migration events commonly known as Anglo-Saxon (a better term to include the 9th Century surge could be Anglo-Danish), has been exaggerated. They concluded that the modern English had only 10% to 40% descent from these Continental immigrants, with the remainder majority reflecting earlier Iron Age / Romano British ancestry.
An independent 2016 investigation by Schiffels, Haak etal looked at ancientDNA from cemeteries in Cambridgeshire. The results supported POBI's conclusion, proposing:
'East English population derives 38% of its ancestry from Anglo-Saxon migrations'
This has quickly shifted into the domain of public lore. That the Anglo-Saxons did not displace the local Britons, that they did merge, with those of British ancestry assuming Anglo-Saxon culture, and that the modern ethnic English of local descent, have only a minority of Anglo-Saxon ancestry.
There were criticisms of both studies. POBI had been based on the DNA of modern populations. Whilst the Haak, Schiffel etal study contained too few ancientDNA samples.
A new study published in 2022, by a similar research team:
This study has been based on far more samples of ancientDNA. A total of 460 NW Europeans including 278 individuals from England. In conclusion, they continue to emphasise admixture, a merging, and the adoption by some people of local descent, of Continental Northern European (Anglo-Saxon) grave goods. They managed to map local family histories of merging population.
They increased the projected impact of Continental Northern European DNA on the British genome.
A recap:
POBI 2015 suggested 10% - 40% Anglo-Danish
The small scale Schiffels, Haak etal report of 2016 suggested 38% 'Continental Northern European' (Anglo-Danish) in the Cambridgeshire region.
The 2022 study based on hundreds of ancient remains increased the percentage of new arrivals. They conclude that it is higher further east, closer to the North Sea, but declines as an average in Western England. At its peak in Eastern England, they projected that Anglo-Danish accounted for 76% of the genome:
'the individuals who we analysed from eastern England derived up to 76% of their ancestry from the continental North Sea zone, albeit with substantial regional variation and heterogeneity within sites.'
This is a higher estimate than that proposed by the previous two studies.
The discussion was not restricted to the percentage of this Continental Northern European DNA. They also examined the origins of these early medieval immigrants. They concluded that they had arrived from a belt across Northern Europe that focused on Frisia, North Germany, and Denmark. They also suggest a smaller, secondary population from further south that might be Frankish. Finally, they detected that this immigration event extended for longer than previously thought, extending into the 8th Century CE, and blending into the Danish settlement.
One fascinating find, I will discuss in another post, concerns the remains excavated in Kent of the UpDown Girl. Just as a taster:
A small caveat. None of these genetic studies can distinguish between Anglo-Saxon DNA and the later, Medieval Danish DNA. Hence, it might be better to consider this as Anglo-Danish. But in some ways, the 9th Century was a fresh surge of the same immigration event.