perjantai 9. kesäkuuta 2017

British Viking Age samples placed on the genetic map

I got recently new samples from quite a new study, link here.   It looks more like a technical test than actual sampling for a purpose to study history, but anyway I sampled the data.  So far I have available eleven Viking Age samples from UK and have now tested them.   The data consist of around ten samples from each population, with exceptions of Swedes.  Only two Swedish samples were available for my mega-snp data base, both from the study "Genomic analyses inform on migration events during the peopling of Eurasia" (Luca Pagani 2016). The first one was from Nyköping, the second was without any place declaration.

The PCA lacks of a few Viking Age samples due to being too bad thus canceled by the outlier check.   British Viking Age samples look like to be German, but I should remind that PCA is based on dedicated components rather than genetic similarity in basis of the whole genome.   Let's see how those samples look in a formal analysis.  I have made several tests to give different views, for the reason that populations don't place in tests on one or two dimensional axis.

We see that in formal tests Swedes are closest to British Viking Age samples, followed by Irish and Scottish samples.  One straightforward conclusions could be that those Viking Age people were mixed Scandinavians and Celts/Britons. One bizarre remark:  Swedish samples are on the PCA prone to bias towards Finns and Norwegian samples show less this kind of similarity.  Still Swedish samples are closer those Viking Age samples from UK.   I have not tested this curio using formal analyses, but as far as I know this will be true in all tests.

edit 11.6.2017  12:50

German samples are from Leipzig.

4 kommenttia:

  1. Some of the Vikings could be Czech. Funny :)
    And here I was figuring out why most of my mother-in-law paternal lineage matches are Scandinavia ;)

    Kuba from Czechia

    1. Czech people are not so far away from Germans. My goal is not to make genetic makeups, I just put things in the open, but you can do it in many different ways. As I mentioned the PCA is based on components and can create misleading results. For example: I have split Finns into two groups (CW-like and locals) in all my tests and usually use both groups on my plots, but now I used only the CW-like group to show the link between Finns, Estonians and Scandinavians. I can do it otherwise too. Everyone playing with PCA's can make different views. The result can be manipulated because we all are admixed in different ways, something common, something not common; we can tune results, especially PCA's and admixtures. So, in many times what you see is only what you want to see. It is easier to agree that what you tell is what you want to tell, but also what you see is not less subjective. In UK and USA all Vikings stories are popular, more popular than in Scandinavia. It directs thoughts, makes values. Using ancient samples can be misleading too. Maybe Saxons, Danes and Swedes were 1500 years ago exactly same people. Today people living in Saxonia can be different people, because Charlemagne killed thousands Saxons, thousands fled away and the rest were subdued and reduced to a kind of serfdom. And for the second, the study didn't mention that those ancient people were Vikings, it only mentioned that they lived in Viking Age Britain. Everything is making stories :)

  2. This finding reminds me of this Danish DNA paper: Nationwide Genomic Study in Denmark Reveals Remarkable Population Homogeneity

    Figure 3 of the article shows that there is twice as much Finnish ancestry in Sweden than Swedish ancestry in Finland. The percentage of Finnish ancestry in Sweden could be in c. 7% range.

    1. Finnish ancestry, or common ancestry of Finns and Swedes excluding Swedish historical ancestry in Finland, is rather poorly known matter. It is also somewhat sensitive matter outside Finland. For safety's sake, both Finnish groups, CW and Local, cluster strictly on PCA because they have common ancestry, but they also differ. Both groups are cleaned of all outliers, it is cleaned of all samples showing tendency towards other populations, including Swedes. My Finns are absolutely Finnish, covering all Finnish speaking Finns. Conversely most commercial services offering genetic ancestry tests use only samples similar to my Local group, and therefore admixtures they get for Finns are incorrect.