DNA ethnicity logic check / Unexpected result

[AndyH81]

Hi all,

I was wondering if those a bit more knowledgeable about DNA and ethnicity estimates might be able to help me out?

A few months back, I did an Ancestry DNA test and failed to match to anyone on my paternal side, only those on my maternal side. Subsequently, my father agreed to do a DNA test and when we got the results, we failed to match as father and son, thus suggesting we're actually not biologically related - although we have not had a legal paternity test yet to 100% confirm this.

If you're bored and want to read that whole story, then the information can be found in this thread: https://www.rootschat.com/forum/index.php?topic=854302.0

Anyhow, I noted that in my results I had lots of close relative matches to two families in Ireland that none of us had ever heard of and, vice-versa, they had absolutely no idea how we could be related either.

According to my DNA ethnicity estimate, my heritage is between 12 - 40% Irish (according to Ancestry) or about 35% Irish (according to MyHeritage, which was done as a separate, independent test). This surprised all of us as none of our family, paternal or maternal, have connections with Ireland either by marriage or breeding (that we know of).

My father's DNA by comparison came back with a result of 0-4% Irish ancestry. Now, in my logical mind, the only way I could possibly have more Irish ancestry than him would be if it came from my mother's side... but I know that not to be true. So, I am making the working assumption that my biological father would, therefore, have to have been Irish or have a lot of Irish ancestry. Is that a fair assumption?

I'll be honest and say that, as I cannot find any logical link between myself and these previously unknown Irish family members, my working assumption would be that my biological father would either have to be a member of one of those families or be closely related to them?

Basically, I need someone to tell me whether or not my hypothesis could be even remotely accurate, or whether I am just using tenuous syllogisms to create a story that is just not there! 

Any help or assistance in understanding this would be greatly appreciated!

Cheers,
Andy

[KGarrad]

But - they are estimates!

Not to be relied upon for serious genealogy

[decor]

If you have close matches with those families in Ireland, and it's not through your mother, it must be through your biological father.
The ethnicity estimates are not an exact science, but the centimorgans you share with those Irish families are definite.

[phil57]

As said above, you need to concentrate on the matches that you have, and research those families and yours to try and establish a connection.

Ethnicity estimates are just that. I have estimated percentages of Scottish, Irish and Scandinavian ethnicity. It doesn't necessarily mean that I or my recent ancestors have any connection with those countries (in the last 250-300 years we certainly don't) only that parts of my DNA share identical regions to those also commonly found in a number of people from those countries. It is more likely that we are all descended from the same people in the more distant past, who came from elsewhere and migrated into those countries.

I have a very close connection to a male who tested with Ancestry, but has only a very small tree and who hasn't responded to my messages. I have spent months researching and building his tree. I have taken some wrong turns along the way and had to retrace my steps, but I now have a reasonable tree of his more recent ancestors, beyond the timeframe that our match suggests.

The only possible connection between us is that several of my ancestors going back 3-4 generations lived in the same town as his great grandmother, some of them in the same street. I have established that his grandmother was born two and a half years after the death of his great grandmother's husband, and that the father named on his grandmother's birth certificate is apparently fictitious, but bears the same forename as one of my great-great-uncles who lived nearby at the time.

I am now pretty certain that the answer to our connection must lie there somewhere, but I doubt I will ever discover the absolute truth unless my match already knows about it, and he's not sharing.

[Rosinish]

I agree with others, the cMs is what matters most with your close matches.

What are your closest 5 - 10 matches (cMs) & relationships on your 'unknown' paternal side & do they match each other?

Looking at ethnicity at this stage is only going to confuse you more (in my opinion).

You may find the Leeds method a great help...

https://www.yourdnaguide.com/leeds-method


Annie

[AndyH81]

Okay, so, as I just stated on my other post: Centimorgans don't really mean a huge amount to me because my knowledge is so limited. Pretty much all I know is that we get roughly 50% of our DNA from each parent.

What I can add to this story is that all of my closest matches come from the afore mentioned strangers in Ireland - and 1 woman in England who also happens to be looking for her real father, and I believe also happens to be connected to the same family in Ireland.

According to our result, we share 7.7% of our DNA (543.2 cM total). The system offered the suggestion of 3 main relationships:

1. Great niece (which is impossible based on what I currently know about my known siblings, though I suppose in this scenario I have to accept there may be more I don't know of);
2. 1st cousin once removed;
3. 2nd cousin.

The other closest relationship was offered as a 1st/2nd cousin with whom I share 5% of my DNA (375 cMs), and then other 2nd/3rd cousins from that family with cMs ranging from 221 cMs - 234 cMs). Those individuals, I believe, are either all siblings or cousins.

Does that mean anything to anyone here!?!? Any tips would be appreciated because I am clearly out of my depth here. *facepalm*

[Ruskie]

It means you’ve sort of hit the jackpot Andy. Those are very high cm matches. 

Have you contacted each of those matches in the hundreds of cms?
Do all of those high matches match each other (as already asked by Annie)?
Have any of them contacted you? (Which may indicate their level of interest and curiosity)

[AndyH81]

It means you’ve sort of hit the jackpot Andy. Those are very high cm matches. 

Have you contacted each of those matches in the hundreds of cms?
Do all of those high matches match each other (as already asked by Annie)?
Have any of them contacted you? (Which may indicate their level of interest and curiosity)

I have indeed contacted them. The "niece" and I have chatted back and forth quite a lot (we contacted each other at virtually the same time), and we can't figure out how we're related. I've come to the conclusion that it's not on my mother's side - but if my father and I aren't biologically related, I have literally no starting point at all because my mother is dead so I can't even get a clue as to who it might have been.

The only thing we know is that of our mutual matches, they appear to be on her mother's side. I have absolutely no idea how I can be related to them - not even a little bit - although my speculation is clearly that it must be on my paternal side, as I can't find any clear connection on my mother's side.

None of the others contacted me. I contacted them all, and got a few non-responses, and the others simply stated they didn't know how we were related because they weren't aware of any family members living in England.

I might have to rope in Davina McCall for this.

[phil57]

Have you looked at Ancestry shared matches for you and your match, if there are any? Are any of them people who you already know of or recognise that link to a specific side/branch of your tree? Do any of them have trees that you can also investigate?