The people after which England is named made up more than three quarters of the nation's genetic ancestry during the early Middle Ages.
Researchers found that the arrival of Europeans between 400 and 800CE, including the Angles from which the word England is derived, accounted for 76% of the genetics of the British population at this time.
While subsequent arrivals have diluted this proportion in the genetics of modern-day Britons, it still represents around half of the ancestry of people in eastern England today. This decreases in the southwest of England, Wales and Scotland, where the contribution from the ancient Celtic populations remains high.
Professor Ian Barnes, a Merit Researcher at the Museum who co-authored the paper, says, 'It's great that we've been able to contribute to this extensive study of the early English, as there's almost no ancient DNA (aDNA) work on the Anglo-Saxon period.'
'The results are fascinating and flag up how significant the change in the population was at this time.'
The findings of the study were published in Nature.
How did Britain change in the early Middle Ages?
The early years of the 400s were one of turmoil in Western Europe, as the Roman Empire lurched from crisis to crisis. While there is no specific date for the end of Roman rule in Britain, it was over by at least 410CE.
At this time, the genetic makeup of England was primarily comprised of Celtic ancestry, with significant contributions from continental Europeans as a result of the Romans. The genetics of Wales and Scotland, meanwhile, remained more distinctly Celtic.
Over the next few hundred years, the arrival of Europeans contributed to the formation of Anglo-Saxon culture in England, which would dominate until the arrival of the Normans in 1066. However, whether this migration was peaceful, or ensured by force, has been debated for many years.
A lack of widespread archaeological evidence had been used by historians to suggest that England was ruled by a small but elite group of Anglo-Saxons which led to the adoption of their culture over time. However, this theory did not explain why in some areas these individuals can be found buried side by side with Britons.
More recently, advances in extracting DNA from ancient skeletons have allowed researchers to sequence the genomes of the long dead, allowing them to infer changes in the population over time.
Dr Selina Brace, a Museum specialist in aDNA and another of the paper's co-authors, explains the process.
'When attempting to extract DNA from bone, we would typically begin by drilling a small hole into it using a drill similar to the kind a dentist might use,' Selina explains. 'This is so that we can drill at a slow speed without generating too much heat that might damage the DNA further.'
'We remove a small amount of bone powder, using chemicals to break down the bone and extract the DNA. Finally, we prepare the DNA for sequencing using a process called library building.'
Previous studies have suggested that the mixing of continental Europeans and Britons provided the basis of Anglo-Saxon ancestry in Britain, along with arrivals from further afield. However, these studies only looked at DNA from a handful of individuals.
By increasing the scope of these investigations to almost 500 human remains, including 285 from England, the new paper provides the most detailed insight yet into the development of the Anglo-Saxon people.
'Earlier, prehistoric time periods have previously been worked on at a similar scale to this study, but they are more straightforward to investigate because population transitions are taking places between groups which are completely different to each other,' Ian explains. 'This means they can be identified more easily.'
'The demographic changes we see in the Anglo-Saxon migration are between groups that are comparatively closely related to each other, so you need more sophisticated techniques to identify them.'
How did the Anglo-Saxon migration affect early English genetics?
The researchers found that the new arrivals into England following the collapse of the Romans shared the greatest similarity with the genetic makeup of remains from northern Germany and the Netherlands, as well as Denmark and southern Sweden.
The arrival of these people began in the mid-400s and continued until the 800s. However, the combination of the original British Iron Age ancestry with these new arrivals is not sufficient alone to explain the genetic makeup of individuals during early Medieval England.
The researchers found that an additional wave of migration with French Iron Age ancestry was necessary to explain this discrepancy, with the people of East Anglia in particular having significantly higher genetic contributions from this group.
Both waves of arrivals from the continent were focused on England's east coast, with their genetic contribution petering out towards the southwest of the country and in the UK's other nations.
The fact that the Europeans contributed some three quarters of genetic ancestry to English people at the time means that the arrival of new populations from the continent was likely the result of ongoing mass migration rather than by the influence of a smaller, elite group.
Analysis reveals there was no detectable difference between the number of men and women arriving in England, suggesting that an invasion by an army of fighting-aged men could not alone be responsible for the observed changes in genetic ancestry.
There is some evidence of integration between the groups, with men of all backgrounds equally likely to be buried with grave goods that indicate higher status.
However, in other areas, people of European ancestry were buried separately from native Britons, while women descended from European arrivals were more likely to be buried with grave goods that indicate higher status. As a result, it is unclear how socially separated the groups were.
To further investigate how European ancestry spread across the country, the researchers have suggested further aDNA sampling of early Middle Ages remains from southern England, Wales and Scotland.
They also suggest sampling remains from the Norman period to provide greater insight into how the genetics of the burgeoning nations were diluted by a new influx of arrivals almost 1000 years ago.
