Unknown 3 x great grandfather - could DNA help?

[LizzieL]

Is there any way that a DNA test could identify an ancestor that far back (assuming he had proved descendants and they had also tested)?

My 3 x great grandmother Ann had a relationship with an unknown man and the result was my 2 x great grandmother Sarah. Sarah's daughter was my great grandmother Elizabeth. Elizabeth's son was my paternal grandfather.
As I understand it, my grandfather would have had a 25% chance of inheriting this unknown man's x chromosome, but it wouldn't pass on any further in the family.

Has anyone any advice, please.

[medpat]

I am in contact through our DNA with a male distant cousin.

His great great great grandmother Ann is the sister of my great great great grandmother Harriet. Ann and Harriet's parents were born about 1790 and about 1794 (baptism or census records).

The DNA of our 4th great grandparents went through male and female lines to get to both of us as 4th cousins. This is one generation further back than you are asking about. I believe you have a chance of finding the family but the individual may be impossible as I don't know how you'd separate him from his closest male relatives.

Hope this helps you decide what to do.

[Pheno]

Yes DNA would go that far back - several of my matches are 4th/5th cousins.

The latest DNA match I have is through a set of 4 x great grandparents who were born 275 years ago.

Pheno

[hurworth]

You would want as many of Sarah's descendants via different lines to test as possible to have any chance.

Is your grandfather alive, or any of his siblings?  Did Elizabeth have siblings, and if so did they have children?

With DNA we have been able to confirm who a gtgtgt-grandfather was, but we did have a name.  Without a name I think it would be difficult.  His gtgt-granddaughter from his marriage matches 7 (and counting) descendants of her gt-grandfather's half brother.  They range from her half3C1R to half3C3R.

Her daughter is a match with four of the seven, so you can see how it's best to get the older generations to test.

On the other hand, still can not identity any matches via a different line.  It's as if this gt-grandfather managed to avoid being recorded anywhere before he emigrated OR somehow his name changed when he emigrated and it stuck.  But that will need more of his descendants to test.     

 

[LizzieL]

Unfortunately my grandfather and his siblings died many years ago. He had three sisters, one died as a child, the other two married but neither had any children. Three of his brothers had children and some of their children and grandchildren are likely to be alive.

Elizabeth had several siblings, I have so far found marriages and children for three of them, but not traced any further than the first generation yet, but a good chance that there are some descendants still living.