DNA ethnicity logic check / Unexpected result

[Rosinish]

I do know that the grandmother of my highest match lived on the same street as my own grandparents at about the same time.

It seems more than a coincidence i.e. do you know what children the g/parents had & with such high cMs, is it possible your match may be a half sibling?

Annie

[Rosinish]

Having spoken more with the closest match, it seems it is possible that one of her grandfathers is a candidate for my biological father. I believe he would be English, but his wife was born in Ireland and would be the connection to the Irish family (I think!).

If your biological father was English & his wife (who is no blood/DNA relation to you) was Irish then that would be a coincidence as you'd have none of her Irish blood.

Annie

[AndyH81]

I do know that the grandmother of my highest match lived on the same street as my own grandparents at about the same time.

It seems more than a coincidence i.e. do you know what children the g/parents had & with such high cMs, is it possible your match may be a half sibling?

Annie

The only child I know for certain the grandparents had was the mother of my closest match. I suppose it's possible she might transpire to be a half-sibling. She's going to do a DNA test, but I have no idea when... after Christmas, I guess.

I know the following facts about the match's family:

Her grandmother was born in Ireland and is the connection to the Irish family.
Her grandmother has 2 sisters and at least 3 brothers, but the brothers are all dead. If we assumed the suggestion of 1st cousin once removed, then it would be one of those brothers (most likely) who would be my dad.
Her grandfather was adopted and isn't sure of his heritage - although they do know his family are from the same town I am from. I don't know whether this is his adopted family or biological; I assumed the former.
The grandparents had two children (that I know of): her mother and her uncle. Her uncle died when he was 15 in a crash in my home town the year I was born. I did the maths in my head and I don't think there's any chance at all he could be my father, so I completely ruled him out as a possibility.

We're both pulling our hair out as we feel like the answer must be staring both of us in the face but we're missing it.

Now, as for my 2nd and 3rd closest match -

2nd -

We have a 5.4% DNA match (379.1 cMs). MyHeritage estimates we have a 1st cousin once removed/2nd cousin relationship. To the best of my understanding, he is in Ireland and is part of the larger Irish family. According to my closest match, she has the same estimated relationship to him that I do.

3rd -

We have a 5% DNA match (375 cMs). Ancestry estimates we would have a 1st/2nd cousin relationship. She is in Ireland and has the same surname as my 2nd closest match, but I have no idea what their relationship is to each other. I've done my own research but cannot find that information and the information available to me on these other peoples' public trees doesn't provide that info. either... although that could be because they're all still living so the information is hidden by default.

[Mowsehowse]

I'm not sure this helps much but..... I just Googled:

(age of youngest father on record)

What a revelation!!  Might just throw your maths into disarray Andy?

[Galium]

So you have your close match's young uncle perhaps visiting his father's relatives in your town. 

If he was accompanied by his father (your match's grandfather), and that man is also your father, you would be related to your closest match, but not to her grandmother's family.

Your post suggests that you and your match's two close relatives are from her grandmother's family, is that right? Or is that uncertain.

I can see two possibilities.  One is that the grandfather (since he doesn't know his background) was born to an Irish woman, and you are all related to his biological family.

The other - well some fifteen year old boys look and behave towards women as if they were much older.

[AndyH81]

Deleted response. Not worth it.

[AndyH81]

Your post suggests that you and your match's two close relatives are from her grandmother's family, is that right? Or is that uncertain.

In so far as I know, yes. But logically, if the grandmother is Irish, then presumably her brother's would be Irish too - either by birth or ethnicity. If one of those grandfathers also had children in Ireland, that could explain why I have such close matches in both the UK and Ireland, right?

And it might also explain why the estimates of 1st cousin once removed keeps popping up?

It's not impossible the younger uncle was my father - but I do know that my mother's taste was generally in older men. Not necessarily massively older, but that's what I know of my father, step-father, and the partners she had between the two. Although I suppose that some younger teens do look older than they are. And she herself was only 19 at the time.

Her mother is doing a DNA test so I guess we can narrow this down pretty quickly:

If younger uncle was my father, the mother will be my aunt.
If uncle's father was my father, she'll be a half-sibling.

If it's another relationship, I guess I might have to go back to the drawing board.

[Galium]

So, it looks as though you can rule out your match's maternal grandfather, and (as the most likely contenders) you are left with either her uncle, or one of her great uncles? Or at a pinch, since I don't know the ages of these people, a son of one of the great uncles.

Against which, you would want to consider who was most likely to have visited your town, since it was the grandfather who had connections there, and not his wife's family.

(Of course, I don't know where you live, and whether is somewhere that anyone from Ireland might pop over to on a visit, or a place which makes it much less likely that that would be the case.)

[Carmella]

Hi Andy,

There is a DNA tool called "What Are The Odds?" I don't know if you've tried it...

You can use it to create a tree with various branches & input shared DNA cM values.
It then generates hypotheses as to where your most likely position in the tree is.

https://dnapainter.com/tools/probability