Anglo-Saxons in Britain; what Genetics has shown so far

According to historical accounts and archaeology, the Anglo-Saxons migrated to Britain from continental Europe from the 5th Century AD. They brought with them a new culture, social structure and language.

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Dr Stephan Schiffels of the Max Planck Institute for the Science of Human History in Germany sequenced genomes of human remains from Hinxton, Saffron Walden, Linton and Oakington – all of which are near Cambridge.

The burials fall into three different age categories: Iron Age, early Anglo-Saxon and Middle Anglo-Saxon.

Contrary to narratives suggesting large-scale displacement of the Britons by Anglo-Saxon invaders, the researchers found evidence of intermarriage in the earliest phase of settlement.

In order to disentangle the Anglo-Saxon signal from the indigenous British genetic background, the researchers looked at many rare mutations across the whole genome.

“We found that these rare mutations were the key to studying historical samples. We could compare our ancient samples with modern samples in an improved way,” Dr Schiffels told BBC News.

“We could look at these in a very large sample of modern Europeans. For example, we studied low frequency mutations that must have occurred in the ancestors of the Dutch over the last few thousand years.

“We found that these mutations were shared with the Anglo-Saxon immigrants at a factor of two more than they are with the indigenous Celtic people. These rare mutations are found only with whole genome sequencing.”

From there, the scientists could track the contribution made by those Anglo-Saxon migrants to modern British populations.

They found that on average 25%-40% of the ancestry of modern Britons is attributable to the Anglo-Saxons. But the fraction of Saxon ancestry is greater in eastern England, closest to where the migrants settled.

(Source: https://www.bbc.com/news/science-environment-35344663)

5-dna

NovoScriptorium brings to your knowledge the following relative published papers:

a) Title: Iron Age and Anglo-Saxon genomes from East England reveal British migration history

Author/s: Stephan Schiffels, Wolfgang Haak, Pirita Paajanen, Bastien Llamas, Elizabeth Popescu, Louise Loe, Rachel Clarke, Alice Lyons, Richard Mortimer, Duncan Sayer, Chris Tyler-Smith, Alan Cooper & Richard Durbin

Abstract: British population history has been shaped by a series of immigrations, including the early Anglo-Saxon migrations after 400 CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences from 10 individuals excavated close to Cambridge in the East of England, ranging from the late Iron Age to the middle Anglo-Saxon period. By analysing shared rare variants with hundreds of modern samples from Britain and Europe, we estimate that on average the contemporary East English population derives 38% of its ancestry from Anglo-Saxon migrations. We gain further insight with a new method, rarecoal, which infers population history and identifies fine-scale genetic ancestry from rare variants. Using rarecoal we find that the Anglo-Saxon samples are closely related to modern Dutch and Danish populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.

Access: https://www.nature.com/articles/ncomms10408

b) Title: Genomic signals of migration and continuity in Britain before the Anglo-Saxons

Author/s: Rui Martiniano, Anwen Caffell, Malin Holst, Kurt Hunter-Mann, Janet Montgomery, Gundula Müldner, Russell L. McLaughlin, Matthew D. Teasdale, Wouter van Rheenen, Jan H. Veldink, Leonard H. van den Berg, Orla Hardiman, Maureen Carroll, Steve Roskams, John Oxley, Colleen Morgan, Mark G. Thomas, Ian Barnes, Christine McDonnell, Matthew J. Collins & Daniel G. Bradley

Abstract: The purported migrations that have formed the peoples of Britain have been the focus of generations of scholarly controversy. However, this has not benefited from direct analyses of ancient genomes. Here we report nine ancient genomes (∼1 ×) of individuals from northern Britain: seven from a Roman era York cemetery, bookended by earlier Iron-Age and later Anglo-Saxon burials. Six of the Roman genomes show affinity with modern British Celtic populations, particularly Welsh, but significantly diverge from populations from Yorkshire and other eastern English samples. They also show similarity with the earlier Iron-Age genome, suggesting population continuity, but differ from the later Anglo-Saxon genome. This pattern concords with profound impact of migrations in the Anglo-Saxon period. Strikingly, one Roman skeleton shows a clear signal of exogenous origin, with affinities pointing towards the Middle East, confirming the cosmopolitan character of the Empire, even at its northernmost fringes.

Access: https://www.nature.com/articles/ncomms10326

c) Title: Evidence for an apartheid-like social structure in early Anglo-Saxon England

Author/s: Thomas MG, Stumpf MP, Härke H.

Abstract: The role of migration in the Anglo-Saxon transition in England remains controversial. Archaeological and historical evidence is inconclusive, but current estimates of the contribution of migrants to the English population range from less than 10000 to as many as 200000. In contrast, recent studies based on Y-chromosome variation posit a considerably higher contribution to the modern English gene pool (50-100%). Historical evidence suggests that following the Anglo-Saxon transition, people of indigenous ethnicity were at an economic and legal disadvantage compared to those having Anglo-Saxon ethnicity. It is likely that such a disadvantage would lead to differential reproductive success. We examine the effect of differential reproductive success, coupled with limited intermarriage between distinct ethnic groups, on the spread of genetic variants. Computer simulations indicate that a social structure limiting intermarriage between indigenous Britons and an initially small Anglo-Saxon immigrant population provide a plausible explanation of the high degree of Continental male-line ancestry in England.

Access: https://www.ncbi.nlm.nih.gov/pubmed/17002951

d) Title: Y chromosome evidence for Anglo-Saxon mass migration

Author/s: Weale ME, Weiss DA, Jager RF, Bradman N, Thomas MG.

Abstract: British history contains several periods of major cultural change. It remains controversial as to how much these periods coincided with substantial immigration from continental Europe, even for those that occurred most recently. In this study, we examine genetic data for evidence of male immigration at particular times into Central England and North Wales. To do this, we used 12 biallelic polymorphisms and six microsatellite markers to define high-resolution Y chromosome haplotypes in a sample of 313 males from seven towns located along an east-west transect from East Anglia to North Wales. The Central English towns were genetically very similar, whereas the two North Welsh towns differed significantly both from each other and from the Central English towns. When we compared our data with an additional 177 samples collected in Friesland and Norway, we found that the Central English and Frisian samples were statistically indistinguishable. Using novel population genetic models that incorporate both mass migration and continuous gene flow, we conclude that these striking patterns are best explained by a substantial migration of Anglo-Saxon Y chromosomes into Central England (contributing 50%-100% to the gene pool at that time) but not into North Wales.

Access: https://www.ncbi.nlm.nih.gov/pubmed/12082121

e) Title: Investigating Anglo-Saxon migration history with ancient and modern DNA

Author/s: Stephan Schiffels and Duncan Sayer

Summary: British population history has been shaped by a series of immigration periods, including the Roman occupation from AD 43 and Early Anglo-Saxon migrations after AD 410. Until recently, the extent to which these events changed the genetic population structure in Britain was an open question. Two recent genetic studies have provided new insight by analys-ing the genome sequences from 19 ancient British samples, dating from between the 1st century BC and the 8th century AD. Here we will review these two recent studies, present a joint analysis of all 19 available samples, and put the results into a wider archaeological context. Key results reviewed here include: 1. high levels of genetic continuity between the Late Iron Age and the Romano-British period; 2. a clear increase in ancestry related to the modern Dutch population during the Anglo-Saxon period, suggesting a substantial arrival of new people during this time; 3. an estimated 38 % average Anglo-Saxon ancestry in the modern English popula-tion; 4. evidence for early admixture of Anglo-Saxon immi-grants and indigenous British inhabitants.

Access: https://www.academia.edu/35607719/Schiffels_S._and_Sayer_D._2017_Investigating_Anglo-Saxon_migration_history_with_ancient_and_modern_DNA

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