DNA to find unknown great grandfather

[Kenneal67]

My wife has a NPE on her family tree and her great grandfather is unknown. After doing Ancestry DNA she has a link at 303cM with a chap. Ancestry states most likely relationship is second cousins. I have now constructed this chaps family tree and one of his great grandfathers is a family very well known and linked to ours. His great grandfather is now in pole position as the unknown person. However could it also equally be one of the unknown chaps brothers?

[Biggles50]

Reading your text it looks like your Wife and her DNA match are of the same generational relationship so that limits the options.

The probability is of the match being a 2C and whilst 303cM is higher than the mean value for this relationship it is still well within the 41-592 of the bell curve distribution of the DNA Painter database.

I would ask a Cousin on the same line to take a DNA test to see if their results also point in this direction.

If there are direct descendants of the presumed Father who respond to contact but who have not taken a DNA test then they could be approach with a view of asking them to take a DNA test could also be worthwhile.

I would also look at the Shared Matches and work them into the Tree as much as you can.

Once you have say 6 other DNA matches linked into the tree then uploading the tree into DNA Painters WATO tool and seeing what the probability options are will add weight to the conclusions.

Uploading her DNA to MyHeritage, ftDNA and Gedmatch may give additional DNA Matches who can be worked into the tree if their cM is high.

In the absense of any legal Paternity case then the above will be as good as it gets.

I would also say that the option of a Brother as you ask would pit the MRCA back a generation which has a much lower probability.

Hope this helps.

[Kenneal67]

Reading your text it looks like your Wife and her DNA match are of the same generational relationship so that limits the options.

The probability is of the match being a 2C and whilst 303cM is higher than the mean value for this relationship it is still well within the 41-592 of the bell curve distribution of the DNA Painter database.

I would ask a Cousin on the same line to take a DNA test to see if their results also point in this direction.

I would also look at the Shared Matches and work them into the Tree as much as you can.

Once you have say 6 other DNA matches linked into the tree then uploading the tree into DNA Painters WATO tool and seeing what the probability options are will add weight to the conclusions.

Uploading her DNA to MyHeritage, ftDNA and Gedmatch may give additional DNA Matches who can be worked into the tree if their cM is high.

In the absense of any legal Paternity case then the above will be as good as it gets.

I would also say that the option of a Brother as you ask would pit the MRCA back a generation which has a much lower probability.

Hope this helps.

Dear Biggles ,

Thanks for taking the time to reply it is appreciated. My wife and this chap are at the same generational level and so my simplistic thinking was that they shared a great grandfather. There are other shared links between my wife and this chap on Ancestry and I have looked at their trees or lack of and they are all a bit of a rats nest.

We do have one cousin of my wifes however who is also  shared match to this guy and we have another cousin of my wifes who is thinking about taking an Ancestry DNA test too

Thanks Again

Ken

[4b2]

I had a similar issue, but not an NPE, rather the family were from India and any records that might shed light on the matter will be in a church there somewhere.

My mother's mother's mother was born in India in 1899/1900. And that's all we knew. From quite extensive cataloging of DNA matches I was able to determine who one of the parents are. This was done by finding DNA matches triangulating seven different matches. However, this has only been possible due to the sheer number of tests I have - 10. With enough tests you can rule the siblings out.

So let's say this theoretical great-grandfather had four siblings. Really you'd need a test from each of their descendants.

I have a similar situation with another match. My aunt has a full first cousin match - doesn't fit in any other way. She was born out of wedlock. So all I can say is that it was not my aunt's father who was the father - it was one of his four brothers. I can make a good guess as to who the father is, but unless one of the children of the other brothers takes a test, the identity can't be known.

[Biggles50]

Ancestry now have their Pro Tool available via an additional subscription.

What I would do in your situation is to ask First Cousins to take a DNA test.

I would also seek out Second Cousins and ask them to take a DNA test.

Then cross referencing the results they should share DNA with your 303cM match and the amount of cM that they share with them and with each other will help pin down the wayward Father.

If the 303cM is responding to Messages you could also suggest that they download a copy of their DNA and upload it to MyHeritage, ftDNA and especially to Gedmatch.

You could then do the same with your Cousins DNA and use all the tools in Gedmatch to narrow down the segments of DNA that are common to you all.

Plus do continue with my suggestions in my forst post.

You have quite a DNA learning curve to work along.

Good luck.