European Jewish DNA - comparison with me and Dad - advice please

[LouiseB31]

Good afternoon, I am looking for someone with a good working knowledge to help me with my latest genealogical conundrum.

My Ancestry DNA showed I had 5% European Jewish DNA in a range of 0 - 9%. This was an unexpected delight because as far as I knew I was about 95% British and 5% Irish


So I arranged to have my father tested and he has come out as 22% European Jewish on a range of 16 - 27%.

This was even more exciting, but very puzzling.

My question is around the increase from one generation to the next and what it might mean in terms of our working out which relative might have been Jewish. Is the fact that Dad's DNA is at least double mine - using the top of my range and the bottom of his - likely to suggest that one of his parents will be something around double his, say 45% or so?  And does this mean that quite probably one of his grandparents were Jewish? Or might the jump go up much less gradually so that I could be looking at great grandparents?

Thanks very much

Best wishes, Louise

[hurworth]

Hi Louise,

The percentages quoted are estimates only, and will vary if you tested with a different company

Gedmatch (it's free) also has some tools which look at origins/ethnicity, so it would be worth uploading there (and looking for cousins on their database as well).   The percentages are very likely to be different.

I wouldn't assume it's just one ancestor who was Jewish.   It's possible that your father has Jewish ancestry via both his parents.

[JustinL]

Hi Louise,

I'm no expert in this field. However, my father's paternal grandfather was a German Jew, so your thread caught my eye.

If you do a google search for 'European Jewish DNA', you'll find some interesting thoughts on the matter. The thread here http://ancestryforums.custhelp.com/posts/93387c1c44 was particularly informative.

It is important to bear in mind that the results you get back from Ancestry are a comparison with other results in their database, the vast majority of which derive from inhabitants of the USA. That is to say, that your DNA is not being compared with a large number of DNA samples taken from people living in our part of the world.

Presumably, you know quite a bit about your father's four grandparents, not to mention his grandparents.

Is there any suggestion that any of them were born outside of the British Isles?

Justin

[LouiseB31]

Thanks Justin, I appreciate your comments and will send you a private message on the subject if that is okay.

[LouiseB31]

Thanks to Hurworth for the advice. I have uploaded the raw data onto GedMatch and FamilyTreeDNA and have found over 1000 matches - that is people with some of the same DNA. Many of them Jewish. Unfortunately there is no-one nearer than 5 generations at the moment but we press on....

[DevonCruwys]

Louise

You might have to look at the ISOGG Wiki page on autosomal DNA statistics:

http://www.isogg.org/wiki/Autosomal_DNA_statistics

We would normally expect to receive about 25% of our DNA from each of our four grandparents. However, there is in practice considerable variation and you might get 19% from one grandparent and 29% from another grandparent. Admixture tests aren't usually that reliable beyond the continental level but they can detect Ashkenazi Jewish DNA with reasonable confidence. Your results are being compared with reference populations.

The results are consistent with your dad having one Jewish grandparent, though they would also be consistent with him having two half-Jewish grandparents. As you only receive half your DNA from each of your parents it would seem that by chance a lot of the Jewish DNA hasn't been passed on to you.

In order to isolate the line on which the Jewish ancestry falls it would help to test other close family members such as first or second cousins to see who else picks up the traces of Jewish ancestry. Your father could also take a Y-DNA test to see if he has Jewish ancestry on his Y-chromosome lineage (his surname line).

[LouiseB31]

Thanks very much for the reply DevonCruwys

Things have moved on a little bit since I posted this thread and exactly as you suggest, we have been able to identify what is euphemistically called a non parental event. One of his biological grandparents was indeed Jewish and by cross matching other tests, including a cousin, I was able to identify which one. There was hardly any likelihood of any Dad's ancestors ever meeting someone Jewish, so it is only on one side as I thought it must be.

Isn't DNA a marvellous thing, I am now triangulating lots of trees of Jewish people with DNA matches to Dad, within about four generations, in the hope of eventually landing on at least the right bit of the family, if not our actual ancestor.

My only disappointment is that the 30 years of work I did on the tree of the grandparent that is not now correct (with the help of innumerous rootschatters) is now irrelevant to us, although still relevant to others in the family whose genealogy has not been, ahem, compromised.

Thanks again for chipping in and confirming - if you had spotted this and replied two weeks ago I would have kissed you. I lay awake for several nights trying to work out the maths and the likelihoods. Thankfully I got there anyway with various people's help sending me articles, just like to you, to read etc.

It's the most exciting thing to have happened in years, family tree wise, I am absolutely delighted.

[DevonCruwys]

Louise

That's great news. I'm glad you were able to work it all out. It is exciting when DNA reveals these previously hidden secrets. I'm sure there will be other people who will benefit from all the other research you've done.

[LouiseB31]

Just to let everyone know that my Jewish great grandfather has now been identified. I know who he was and lots of detail about him. I even know how and where he met my great grandmother. The only thing I do not have is a photograph and I have already exhausted every avenue. So that's a shame. I eventually found him when I persuaded my father's sister to test with 23andme, and up popped two second cousins who had not tested on any of the other platforms where our DNA had been put. So if nothing else, do consider testing with them too if you are equally struggling. It took me four years to do that, otherwise I could have had it boxed off long since.