Reconciling DNA results against what is known of father's (half-German) ancestry?

Question

I am unsure of who my father is (was).

The man I was told was my father is now deceased. His mother was born in Mannheim, Germany and she came to the US after the war. She had my dad which would have made him half German.

I did a DNA test through ancestry.com and received my results yesterday and I have 0.00% German heritage.

Does this mean that this man is not my father?

The test said I descended from Great Britain at 76%. Can anyone tell me what this means in further detail? Or if I should start looking somewhere else?

Answer 1

This test that you describe is not even remotely a paternity test. These ethnicity tests are only best guesses based on samples of currently or recently living people from those regions. They could totally miss many or all of your father's haplotypes just by random chance, as mentioned in this article from Scientific American:

even if an individual's ancestors did hail from [a specific region], if their particular lineage (as captured in their sample) does not match up with reference sequences, some tests will turn up with no family tie.

If you really want a definite answer you would need DNA from one of his living relatives (or from his body) and you would want a test done that is specifically designed to determine if someone is a close relative.

In this blog post, the author mentions that a grandparent and grandson may share 12.5-33.8% of their DNA. What that really means is that they would share that much of the variation in their DNA, because in reality your DNA is over 99.9% identical to the DNA in any other human. Very little of it varies at all.

Answer 2

Ancestry ethnicity estimates isn't able to differentiate German ancestry. It is most likely classified as Europe West however depending on where in Germany they are from, it is possible that German ancestry can be classified as Europe East or Great Britain.

On top of that, these estimates are just a guess. https://www.legalgenealogist.com/2014/05/18/admixture-not-soup-yet/ does a good job describing the weaknesses in the results. I would focus more on the DNA matches you find.

Answer 3

When you did the DNA test you may not have asked for both maternal and paternal DNA, and I know some sites only do both if you ask them to. My uncle had his done for both and we got some surprising results too.

We had always been told that my grandmothers family were totally Norwegian but the DNA said that there was a lot of European Jew in our DNA also. My uncle didn't use the Ancestry site so I can't speak to how they do the test but I wouldn't take it as meaning he isn't your father.

Just because someone is born in Germany doesn't mean that their heritage is purely German. You also haven't mentioned where your father's father is from.

You also stated it was only 76%, so perhaps consider the rest. I would not stress too much, it just means you have more digging to do and a mystery to solve.

Answer 4

Your mother could well have been of English heritage with parents who moved to Germany when she was young enough to simply go with them. Many parents and grandparents have been mum about various aspects of their birth because they could not foresee the socially accepted customs changing.

I've had autosomal DNA TESTS from ftdna.com & ancestry.com because my father has no brothers or sons and he is now long deceased. FTDNA.com gave me a much more scientific results that are much more consistently available to me. I am 31% Ashkenazi Jew from Lithuania. I'm proud of that. My father is German and Jewish, my mother's heritage is British Isles.