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Understanding the "British Isles" DNA results

Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 1:35PM GMT
Classification: Query
I have received my DNA results and am a little bit confused as to how they should be interpreted. My results showed that I am 98% British Isles and 2% Uncertain. All my ancestors on my Tree do come from the British Isles so this is not the issue.

My confusion is due to not being able to interpret what "British Isles" really means. I know that the British Isles were a crossroads for many different cultures - including Scandinavian, among other peoples. Therefore, I would have expected some breakdown in the ethnicities shown for a person who is so strongly "British". But this is not the case for me and for many others.

My question is: Is there a real "Briton" that is genetically distinct and detectable? Or is "British Isles" simply a typical blend - kind of like a standard seasoning? (A little of this, a pinch of that?) What does it mean to be "British" and why is it not broken down into the separate ethnicities that contributed to this "Britishness"?

Thanks!

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 10:12PM GMT
Classification: Query
Edited: 6 Dec 2012 10:15PM GMT
I could use some help understanding this as well. I am also interested in understanding more about the different groups there, in particular Celtic. I had not realized they were located in so many areas?

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 10:53PM GMT
Classification: Query
Thank you for your reply. Having read a little bit more on the subject, I have come to realize that DNA does not come down to us as a neat package from both sides, and in equal amounts. It seems to be a rather random recombining of genetic material, so that quite a bit is lost over the centuries. One blog site suggested that in 10 generations we might receive DNA from as few as 10-12% of individuals in our family tree, which surprised me.

However, I would still like to know how the test shows our DNA as falling into a typical "British Isles" group, particularly after so many centuries of invasions. Those changes continue to the day, with the addition of Indian, Pakistani and African peoples (among others) into the British Isles, so I imagine that whatever it means to be "British" will one day change even further from what it is at this time. But what does it all mean at this moment in time? I would have expected to have seen at least some "Scandinavian" in my results, since my mother's family came from a Viking settlement in the Scottish Highlands and her surname carried that place name down to the present day.

I have understood that siblings may carry quite different results from each other and also that the more direct family testing is done the better and more accurate the results might be. I will consider having the rest of my family tested, if I can afford it, to see if we eventually get more nuanced results.

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 11:08PM GMT
Classification: Query
Having "British Isles" in your results simply means that your pattern of Ancestry Informative Markers (AIMs) is statistically similar to those of a reference sample of individuals whose ancestry can be traced to that geographic area. Because the British Isles are a complex region, those individuals represent a mixture of more ancient ethnicities. There is an interesting project that you may want to google called "People of the British Isles: The Face of Britain." If you are interested in deep ancestry, you may also want to get YDNA and mitochondrial DNA tests and join the haplogroup projects at Family Tree DNA or get the new National Geographic Geno 2.0 test. I have done YDNA and that indicates that my paternal lineage can be traced to a proto-Celtic culture that arose some 3000 years ago in Central Europe. I am eagerly awaiting my Geno 2.0 results.

Jim

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 11:15PM GMT
Classification: Query
That is very interesting, Jim. Your deep ancestry results are really exciting! I am considering doing the NatGeo Geno 2.0 test as well. For a paternal lineage I'd need the cooperation of my Dad, who thinks this is all silliness, but I do not agree. It's science and it is new, so I'm on board. Thanks for your feedback and congrats on your interesting results!

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 11:16PM GMT
Classification: Query
That is very interesting, Jim. Your deep ancestry results are really exciting! I am considering doing the NatGeo Geno 2.0 test as well. For a paternal lineage I'd need the cooperation of my Dad, who thinks this is all silliness, but I do not agree. It's science and it is new, so I'm on board. Thanks for your feedback and congrats on your interesting results!

Re: Understanding the "British Isles" DNA results

Posted: 6 Dec 2012 11:23PM GMT
Classification: Query
The Geno 2.0 project is testing a number of recently discovered SNPs and promises eventually to permit a much more detailed breakdown of haplogroups. My current haplogroup assignment is R1B1A2A1B3C-L2. Others in that group trace their ancestry to Northern France, the British Isles and Denmark, which is consistent with my documented family history that indicates my paternal ancestors were part of the Norman-Welsh invasion of Ireland in the 12th century. I am hoping that the new results will help to bridge the millennia between the current findings and the written record.

PS--when Ancestry eventually releases the raw data you can use the various admixture/ethnicity calculators available at Gedmatch for more detailed analyses using different reference groups.

Jim

Re: Understanding the "British Isles" DNA results

Posted: 7 Dec 2012 1:46AM GMT
Classification: Query
wrote this in response to a private questions, but it might be of general interest.

Your ethnicity analysis is based on the identification of specific Single Nucleotide Polymorphisms (SNPs). The computer generates a listing of your values and compares it with reference populations. These are groups of individuals who have been tested and who have documented ancestry in a particular region. Ancestry has not released its list of reference populations but FTDNAs can be found in their FAQ. You will see that not every region of the world is listed, and some regions contain a mix of populations. An example in FTDNA's analysis is "Orcadian," residents of the Orkney Islands off Scotland, who combine Anglo-Saxon, Scottish (Pictish), Norman, Scandinavian and other groups. The computer looks for a close fit between you and the reference populations. If you fit exactly (within a statistical margin of error), your ethnicity will be given as 100%. So that means that you fit the Ancestry reference population for British Isles, whatever that is, not that all of your ancestors were British.

The matches are done differently. There the computer looks at blocks of SNPs on each of your 23 chromosomes. It finds other people who share a particular segment. Again, Ancestry doesn't tell us what numbers they are using, but FTDNA typically looks for at least 7 centimorgans, which is a measurement of the number of base pairs shared. If you share several segments, or even one long segment with another person, the computer calculates the probable number of generations back to your common ancestor and estimates a relationship.

So here's an example of how that might work in practice. I have an ethnicity analysis of 93% British Isles, 7% other. I have documented German ancestors, who are incorporated into the British percentage because of a common Saxon or Celtic ancestry. Imagine that my German ggg grandfather, who lived in Bavaria, had a brother who went across the mountains to Switzerland to work. There he met an Italian woman and they had daughters. Some of their daughters married Italian men, but one went to North Africa and married a Berber. So there might now be German, Italian and Berber individuals, all of whom carry my gggg grandfather's DNA, and are therefore my distant cousins. But all might also have very different ethnicity percentages.

Hope this helps.

Jim

Re: Understanding the "British Isles" DNA results

Posted: 7 Dec 2012 11:34AM GMT
Classification: Query
This does help. So, a "British Isles" designation indicates a particular, predictable mix, somewhat like a box of Old Bay seasonings are always Old Bay seasonings, no matter what the recipe in which it appears? In my case this all makes perfect sense because everyone I have found on my Tree have been from the British Isles. What I expected to see, however, was more of a breakdown of ethnicities that make up the British isles, such as Scandinavian, Saxon, etc. Perhaps this is not really the test for such detail, or else the samplings are still too new?

I am still a little bit confused as to how people with nearly exclusive German and Russian ancestry on their genealogical Tree are related to me as fourth to sixth cousins, unless I have not uncovered aunts and uncles who married into more German families, or their children did? I mean, how far back is fourth cousin? Certainly within recorded genealogy, right? Yet I have not been able to see it as yet on my Tree...

The "Uncertain" designation poses its own mysteries, but not terribly so at only 2%, and I wanted to be clear about what this test was giving us.

Thank you, Jim, this is fascinating!

Re: Understanding the "British Isles" DNA results

Posted: 7 Dec 2012 4:35PM GMT
Classification: Query
Surnames: Mansfield
My DNA results were very similar. Mine were 97% British Isles and 3% unknown. Honestly, I was a bit disappointed if one can be disappointed in one's DNA. It's just that I wanted one of those multi-colored pie charts. I wanted more diversity.

And I'm surprised that there wasn't at least some Scandinavian in my results which is mixed in with most people of British ancestry. I guess for those of us that come out so high of a percentage of only one group of people, we can at least say our ancestors were good at hiding the women during various invasions :-)

I am going to get a second opinion (and maybe a third and a fourth), though. I've just sent back my comprehensive genome kit to FamilyTree DNA. This will test Y-chromosome, mitochondrial, and autosomal DNA. I also joined the Mansfield DNA project. After that, I will probably go ahead and take part in the National Geographic project and get tested by 23andme, too.

It'd be nice if some of these test results were merged so I wouldn't have to spend as much. But as it is, I'd rather see myself tested as comprehensively as possible to ensure accurate results. Moreover, I'm hoping to discover a branch of the family that got "lost" through adoption a couple of generations back. This will only work if they are testing, too, and there's no way to know which service they might be using.

Regardless, I think it will interesting to compare my ancestry.com's 97% British results against the FamilyTreeDNA results in a few weeks.
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