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Sunday, May 1, 2016

Ancient Polish admixture in Denmark

This ESHG 2016 presentation about Danish population structure is sure to be interesting. I wonder how the authors were able to discern ancient Polish admixture from more recent Polish admixture? Keep in mind that lots of Poles settled in Denmark during the past 150 years or so. For instance, former Danish national team goalkeeper Peter Schmeichel is half Polish. And Caroline Wozniacki is totally Polish.

Abstract: Denmark’s genetic history has never been studied in detail. In this work, we analysed genetic and anthropometrical data from ~800 Danish students as part of an outreach activity promoting genomic literacy in secondary education. DNA analysis revealed remarkable homogeneity of the Danish population after discounting contributions from recent immigration. This homogeneity was reflected in PCA and AMOVA, but also in more sophisticated LD-based methods for estimating admixture. Notwithstanding Denmark’s homogeneity, we observed a clear signal of Polish admixture in the East of the country, coinciding with historical Polish settlements in the region before the Middle Ages. In addition, Denmark has a substantially smaller effective population size compared to Sweden and Norway, possibly reflecting further lack of strong population structure. None of these three Scandinavian countries seems to have suffered a depression due to the Black Death in the Middle Ages. Finally, we used the students’ genetic data to predict their adult height after training a novel prediction algorithm on public summary statistics from large GWAS. We validated our prediction using the students’ self-reported height and found that we could predict height with a remarkable ~64% accuracy.

Athanasiadis et al., Nationwide genomic study in Denmark reveals remarkable population homogeneity, ESHG EMPAG 2016 Presentation Abstract, P18.091C

Update 24/08/2016: The paper is now available at Genetics and open access. See here: On the remarkable genetic homogeneity of Denmark.


FrankN said...

I wonder whether "Polish" is the adequate term here, "West Slavic" (Obotrite/ Wagrian/ Rani/ Pomeranian) might be more appropriate.

There is little doubt about early medieval interaction between Danes and West Slavs. Rügen (Rugians/Rani), and Fehmarn (<-"po more", Obotrites) were under Danish control for prolonged periods, Pomerania was Danish until 1227.
Add to that:
- some 50 "wendish" toponyms on Lolland, Falster, and Mön, e.g.
- a century-long early medieval tradition of Obotrite rulers marrying Danish Queens,
- the well documented multi-cultural emporia along the SW Baltic coast (Stargard/Oldenburg, Liubice/Old Lübeck, Rerik/Groß-Stömkendorf, Wolin/Jomsburg etc.) with West Slavic-Saxon-North Germanic (Danish/Skanian) coexistence not only indicated namewise, but also archeologically (e.g. different burial customs). Roskilde's city neighbourhood "Windeboder" (wendish booths) suggests that this multi-cultural trading pattern also extended to the Danish heartland.
- Intensive high medieval trans-baltic trade, involving (sometimes competing, sometimes co-operating) the Hanseatic League as well as Danes,
- later Swedish control of Pomerania (including Vorpommern), that via Skane should also have acted on Eastern Denmark,
- Danish rule over Holstein, including a good part of previously West Slavic (Wagrian, Obotrite) East Holstein until 1864, with some of the leading nobility (e.g. the Rantzau family) having Slavic roots.

If such century-long interaction hadn't left genetic traces in the Danish population, it would be a miracle.

I wonder what "East of the Country" means in this respect. I expect it to comprise Bornholm, Lolland, Falster, Mön, and, to a lesser extend, Zealand, maybe also Langeland.

Davidski said...

Yeah, you're right. They probably mean anyone West Slavic from what is present-day Poland and surrounds.

But there were indeed some tight contacts between Poland and Denmark during the early Middle Ages, so some Poles did probably settle in Denmark at that time.

szopen said...


I have a question for you. Since it's of no interest to other blog readers, let me ask it in Polish, if you don't mind.

Kilku studentów informatyki potrzebuje problemu do rozwiązania w systemie rozproszonym. Pomyślałem, że może, zamaist kolejny raz rozwiązywać problem komiwojażera, mogliby spróbować zaimplementować jakiś użyteczny algorytm z genetyki. W efekcie powstałoby w najlepszym razie darmowe oprogramowanie realizujące coś, co może się Panu przydać, a w najgorszym razie napiszą ciekawszą inżynierkę (nawet jeżeli może się okazać, że będzie to czysto akademickie rozwiązanie jakiegoś problemu). Czy mógłby Pan coś zasugerować?

Gdyby Pan był zainteresowany i wolał napisać na email zamiast pisać w tym wątku, mój adres publiczny to szopen małpa europe com

Davidski said...

OK, cool, just sent you an e-mail.

LED Power said...

Nie ma adresu podanego mailowego tutaj i na innych twych blogach, a chciałbym się skonsultować w sprawie użycia twoich arkuszy z frekwencjami komponentów jak K15, k6 itd., w moich analizach statystycznych i parę pytań technicznych. Nie chcę zaśmiecać wątku, odpiszesz na