Iron Age and Anglo-Saxon genomes from East England reveal British migration history
By Stephan Schiffels, Wolfgang Haak, Pirita Paajanen et al.
Nature Communications, Vol.7:10408 (2016)
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.
Introduction: Within the last 2,000 years alone, the British Isles have received multiple well-documented immigrations. These include military invasions and settlement by the Romans in the first century CE, peoples from the North Sea coast of Europe collectively known as the Anglo-Saxons between ca. 400 and 650 CE, Scandinavians during the late Saxon ‘Viking period’ 800–1,000 CE and the Normans in 1,066 CE. These events, along with prior and subsequent population movements, have led to a complex ancestry of the current British population.
Although there is only a slight genetic cline from north to south at a coarse level recent analyses have revealed considerable fine-scale genetic structure in the Northern and Western parts of Great Britain, alongside striking homogeneity in Southern and Eastern England4 in the regions where archaeologists identify early Anglo-Saxon artifacts, cemeteries and communities. A variety of estimates of the fraction of Anglo-Saxon genetic ancestry in England have been given with the recent fine structure analysis suggesting most likely 10–40% .