Wednesday, June 11, 2014

AncestryDNA vs FTDNA & What the Results Tell Me

My FTDNA myOrigins results
Earlier, I talked about the new myOrigins results at FTDNA and how I had zero results for my British heritage even though I have several known British branches in my tree and AncestryDNA puts my British results around 55%, a massive difference - which one do I put more weight in? On one hand, FTDNA's zero British results seems hugely inaccurate but equally, AncestryDNA's estimate of only 5% West Europe (German, for me) when I know I have several German branches and only a 2% "trace amount" of Scandinavian when one of my great grandfathers was Norwegian always felt a little off too.

My results from AncestryDNA, trace amounts are in outline
In my other post, I talked about how FTDNA was probably placing my British DNA into it's Scandinavian and German categories, because the British do have Viking and Germanic tribe influences and my results for those categories are much higher with FTDNA than they are with I've realized that what this may mean is that my British DNA is entirely Viking and Germanic, with little to no Celtic or Roman influence. This idea is supported by the fact that AncestryDNA give me only trace amounts of Irish results (less than 1%). At first, I though this was just because I have no real Irish ancestry - all my "Irish" ancestors were actually from what is now Northern Ireland, which means they are more than likely genetically Scottish or English (shhh, don't tell my half Irish husband). And this may still be the case. But it's also come to my attention that what AncestryDNA mean by "Ireland" is actually more like "Celtic". Additionally, FTDNA seems to suggest that their "European Coastal Islands" category (shown on their map as basically Britain and Ireland), may be their idea of "Celtic" too, because their description of this category says: "This group is typical to the British Isles, especially Ireland." So, I'm getting little to no Irish/Celtic results from AncestryDNA and I'm also showing no results for "especially Ireland" from FTDNA. Maybe the different results from the two companies aren't so different after all, if what they are both trying to tell me is "you're not Irish or Celtic."

What it's also probably telling me is that because my British DNA is so influenced by Viking and Germanic DNA, it is almost indistinguishable from those categories. Depending on the control group samples each company used, my British, Scandinavian, and German DNA will therefore naturally have different percentages and it doesn't mean one is more accurate than the other. When you have two or more groups of peoples who are genetically too similar to one another to tell them apart, it's going to be difficult, if not impossible, to accurately place their DNA. It's probably never going to be accurate to say I'm "this much British and that much Scandinavian" - it will be more accurate to say that apart from my Italian heritage, I mostly come from Viking and Germanic blood, regardless of whether that DNA has more recently come from Britain or Norway or Germany.

At least both companies seem to agree that I am about 1/3 Italian - although with FTDNA, I am getting similar influences from the Middle East. According to them, I am 17% Middle Eastern but of course, I know there is no one in my tree from the Middle East. What's happening here is very similar to what is happening with my British DNA - that the Italians, particular southern Italians and Sicilians (which are a known part of my ancestry), have had genetic influences from the Middle East and therefore some of their DNA can be very similar. Even AncestryDNA identified trace amounts from the exact same regions of the Middle East - just one example of why you shouldn't always dismiss those trace amounts as statistical noise.

While it's easy to lump those Middle Eastern results into my Italian ancestry because I have no Middle Eastern ancestors, it's more difficult to distinguish my British, Scandinavian, and German DNA because I do have ancestors from all of those places. But if you take a look at the two maps above and ignore the percentages for a moment, it's interesting to see how almost all the circled regions are the same from both companies. They've both identified "West Europe" or in this case, my German heritage. They've both identified my Scandinavian - or Norwegian heritage. They both identified some small amounts from Finland/NW Russia which I think is coming from an influence on my Norwegian ancestors. And they've both identified my Italian DNA with it's Middle Eastern influences. The only thing missing from FTDNA is a circle around the British Isles, which I think I've been able to explain, and the fact that AncestryDNA's results has less than 1% from Asia South, which is essentially India, but I'm pretty sure this is just statistical noise or somehow again related to my Italian ancestry.

Still, FTDNA results like this can be very misleading for people who don't take the time to consider these possibilities. Equally,'s "trace" amounts of my Scandinavian DNA might be misleading too, when it may be higher than that. There is so much to consider and my varying percentages from these two companies just goes to show that DNA is not such an exact science yet after all.

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