Posted today on Anthrogenica by JonikW:
The first of the aDNA presentations now: “The Anglo-Saxon migration and formation of the early English gene pool”, Stefan Schiffels and Joscha Gretzinger.
Gretzinger (speaking very quickly throughout) started by saying about 80 people have been working on this since 2018 (including Schiffels as a PhD student). Gretzinger started off by looking at earlier studies including POBI. Then he turned to their own work. This is a map of sites the study looked at to find out the true picture:
https://i.imgur.com/Ftq9RPU.png
England forms a cline between Wales and Scotlands and the Netherlands and Germany on a PCA. In the Bronze and Iron Age, England clusters with other Brits. But the 285 new samples sit with the northern Germans and Danes.
The Early Medieval English are genetically closest related to northern Germans, Danes and Dutch. Most sites in England have majority ancestry from the Continent at this time.
Y chromosomes: haplogroup I1 is the big development. Around 76 percent of the paternal ancestry in the study comes from the continent. They also arrive at a level of 76 percent using the autosomal data alone.
https://i.imgur.com/bcEAgC9.png
Mitochondrial dna. Women were also involved in the migration.
Where did the continental incomers come from?: Nearly exclusively Northern Germany and Denmark. There is a “nice cline from the northern Netherlands to southern Sweden”, but mainly concentrated northern Germany and Denmark.
Impact of the migrations on the modern population: It’s not possible to model English as a simple two way mixture between the iron age population and northern Europeans.
We think a better model for modern England involves a mixture between the IA Brits, early English and some French ancestry.
A three-way admixture model for the present day population has to include French.
French ancestry 43 per cent in east Anglia and also strong in Kent.
Conclusions in bullet points:
We detect 76 percent ancestry replacement during the Early Middle Ages in England
We find no evidence for sex bias in the admixture process
We identify Lower Saxony and Denmark as the most plausible geographic homeland of those immigrants.
Admixture was heterogenous across England and follows an East to West cline
Continental ancestry was later diluted by southwestern European ancestry.
They now want to understand how this later French ancestry entered England (he mentioned David Reich is working with them).
Points from the questions and answers at the end: they have 30 early Medieval and 10 Iron Age samples from the Netherlands (I’m not sure whether those all belong specifically to the study because he mentioned they don’t have English IA samples of their own). Norway was not sampled specifically for the study but it looks different from the key areas discussed here including Denmark. Samples were mostly taken by archaeologists. Next they need to sample the west of England more and be careful to avoid bias of sites. They admit that “one of the major issues” is that they have is that they don’t have Roman samples from Britain. But this large-scale change that we see in the Early Medieval Period in England is NOT Roman Period”. They know this from studies that they have access to but that are not published yet.
