Half First Cousin or not??

[grahamm684]

Hi, I have a potential first Half cousin, recently discovered who if its true we share the same Grandad. He was with my Grandmother for a time and they had a son, my Dad, and then he married and had another son who had a daughter.
The only proof was Grandmother's say so which was good enough to stand up in court, and fight off an appeal.
Recently the daughter my potential half first cousin had an Ancestry DNA test, this said she had 4% in the area that her Grandad came from, but I have nothing.
Would you say that this means without any doubt that we are not linked or matched, and that my Grandmother had it wrong.

Kind regards,

Graham

[David Nicoll]

Hi,

   I would say this tells you nothing, 4% from a region, which is a notoriously dubious calculation could easily be zero, or simply someone else who has a link to the area in question.
   The real question is what is the cM match between you and your potential first half cousin.
   Check using the DNA painter, shared DNA tools, for a little more clarity.

   

[SouthseaSteel]

Hi,

   I would say this tells you nothing, 4% from a region, which is a notoriously dubious calculation could easily be zero, or simply someone else who has a link to the area in question.
   The real question is what is the cM match between you and your potential first half cousin.
   Check using the DNA painter, shared DNA tools, for a little more clarity.

 

Totally agree. Regional ethnicities at this level are meaningless.  However, half 1st cousins share very significant amounts of DNA at ca. 500 cM which would absolutely confirm such a close relationship between you.   

[jaywit]

My half 1st. cousins share between 200 and 250 cM with me to give you an idea.

[ReadyDale]

Try entering your cM numbers here:
https://dnapainter.com/tools/sharedcmv4
It'll give you a better idea of what relationships are likely

[Biggles50]

Go by the cM value and that indicates that the Daughter of your probably 1/2 1C should share about 224cM with you, although anywhere in the range is 62-469cM would still be pretty conclusive.

[Wexflyer]

Sounds to me like Graham may not have done a DNA test himself? Or my not have done an actual comparison to the putative half cousin?

[Glen in Tinsel Kni]

Ethnicity and regions do nothing to identify ancestors. The overlapping shared dna amounts between full and half cousin matches make it difficult to be certain which is correct when looking at results between two individuals in isolation. More reults re needed to be definitive and in some cases target testing is the only way to be sure. 

On paper I have 1c1r matches but the shared dna fits both 1c1r and h1c1r. After target testing their father (on paper my 1c), and finding he shares jut 350cM to me we instantly knew that part of the family are half relatives to me. It also answers why I'm the only one who matches two large group of mystery matches and confirmed my mother is an NPE.

[grahamm684]

Well, Thankyou for all your replies, but I am a total beginner with DNA. So I am completely blown away as what to do next.
I did an Ancestry Dna, test and I believe my potential cousin did recently, my results are registered on my tree and have many 1st 2nd 3rd cousin suggestions but not the one I am looking for here. I thought when she had done her test then it would show up with the  rest??
Anybody able to expand on a way forward for a beginner??

Cheers!