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General => Ancestral Family Tree DNA Testing => Topic started by: MrsS2012 on Wednesday 03 June 20 17:32 BST (UK)

Title: DNA Query
Post by: MrsS2012 on Wednesday 03 June 20 17:32 BST (UK)
Hi all,
So one of my cousins got in touch with me yesterday, we haven't spoken for years but she recently took a DNA test through ancestry and had heard that I had also taken one and was working on the family tree so suggested we work together.
Had a chat with her earlier on the phone and we've managed to find each other's trees on the ancestry site.. however it says that we are not a DNA match.. yet our fathers are brothers?
We also went through the list of matches that we have been given and none of them match.. it seems we share no common ancestors at all?
I'm quite confused by this and am now questioning the accuracy of the DNA test.
Anyone else had this?
Title: Re: DNA Query
Post by: Gadget on Wednesday 03 June 20 17:38 BST (UK)
If your fathers are brothers, you are 1st  cousins and you should share approx between 396 and 1397cMs.

How long ago did your cousin test as it sometimes takes a while for the Ancestry matching routines to run?

Gadget

Add - did your father have any other siblings?
Title: Re: DNA Query
Post by: MrsS2012 on Wednesday 03 June 20 17:45 BST (UK)
If your fathers are brothers, you are 1st  cousins and you should share approx between 396 and 1397cMs.

How long ago did your cousin test as it sometimes takes a while for the Ancestry matching routines to run.

Gadget

Add - did your father have any other siblings?
It was a while back I think. I can find out exactly.
My father had one other sister.
Title: Re: DNA Query
Post by: Gadget on Wednesday 03 June 20 18:02 BST (UK)
Are either of you in contact with the sister's offspring (if any) ?

Also, is it possible for both of you to check for any possible more distant relatives that you might share DNA with?
Title: Re: DNA Query
Post by: Craclyn on Wednesday 03 June 20 18:14 BST (UK)
The first thing to check is whether both of you are getting other matches that tie in with the set of grandparents you think you share. If one of you is, but the other is not, then this might suggest that there is a discrepancy between the documented family and the biological family.
Title: Re: DNA Query
Post by: MrsS2012 on Wednesday 03 June 20 18:27 BST (UK)
She did the test in January.
She's just linked her DNA to her tree she's told me. Mine was already linked.
Will check again tomorrow.
My aunt has two daughters but neither of them have taken a test.
Title: Re: DNA Query
Post by: Gadget on Wednesday 03 June 20 18:39 BST (UK)
When you look at your DNA matches listing, can you identify any matches who are on your father's side?

Add  it might be an idea if you could both upload you DNA files to a site that has a chromosome browser - e.g. My Heritage or Gedmatch.

(my line is playing up at the moment )
Title: Re: DNA Query
Post by: MrsS2012 on Thursday 04 June 20 09:48 BST (UK)
I've heard of Gedmatch.. ok will look into this.
Title: Re: DNA Query
Post by: Ruskie on Thursday 04 June 20 09:54 BST (UK)
If you are both new to DNA you may find My Heritage easier to use than Gedmatch, however you will both need to pay a fee to unlock the chromosome browser and other features - I think this is worth doing.

Good luck.  :)
Title: Re: DNA Query
Post by: Gadget on Thursday 04 June 20 09:55 BST (UK)
You'll both need to download your DNA data from Ancestry and then upload it to Gedmatch. You will then be able to compare chromosome by chromosome and use other features.
Title: Re: DNA Query
Post by: MrsS2012 on Thursday 04 June 20 16:37 BST (UK)
You'll both need to download your DNA data from Ancestry and then upload it to Gedmatch. You will then be able to compare chromosome by chromosome and use other features.
Thank you. I'll have a chat with her and we will look into this  :)
Title: Re: DNA Query
Post by: MrsS2012 on Monday 08 June 20 13:21 BST (UK)
The first thing to check is whether both of you are getting other matches that tie in with the set of grandparents you think you share. If one of you is, but the other is not, then this might suggest that there is a discrepancy between the documented family and the biological family.
Slightly worried as I am getting matches that tie in with our grandparents but she isn't. The only matches she is finding is from her mother's side?
Haven't suggested Gedmatch to her yet as tbh I'm concerned what it might turn up :-\
Could there be another explanation or is it a likely case that we aren't related after all?
Title: Re: DNA Query
Post by: Gadget on Monday 08 June 20 14:17 BST (UK)
It looks as if it could be a non-parental event or maybe a family adoption- i.e. you're not related.  That's difficult for you  :-\
Title: Re: DNA Query
Post by: avm228 on Monday 08 June 20 15:48 BST (UK)
It looks as if it could be a non-parental event or maybe a family adoption- i.e. you're not related.  That's difficult for you  :-\

I agree - handle with care as this looks like a potentially sensitive outcome with regard either to her own paternity or her father's blood ancestry.
Title: Re: DNA Query
Post by: MrsS2012 on Monday 08 June 20 15:58 BST (UK)
Oh dear.. Possibly opened quite a large can of worms here... I'll let her take the lead on this and decide how she wants to go about it I think  :-\
I guess what I'm asking is.. Is there anyway the DNA test can be mistaken.. Can we still be cousins but just not have the same DNA.. I'm guessing not.
Title: Re: DNA Query
Post by: Gadget on Monday 08 June 20 16:18 BST (UK)
I've not known such a mistake.
Title: Re: DNA Query
Post by: MrsS2012 on Monday 08 June 20 16:46 BST (UK)
I've not known such a mistake.
OK thank you... Awkward situation.. I'll let her decide how she wants to proceed.
Title: Re: DNA Query
Post by: avm228 on Monday 08 June 20 22:19 BST (UK)
There are rare circumstances in which anomalous DNA results are caused by a phenomenon called chimerism, one variant of which involves the absorption and expression of donor DNA by a recipient of a transplant or transfusion. Modern methods of treating donor tissue and blood products make this less likely to happen nowadays (and it was always rare). It’s very unlikely to be relevant but worth mentioning for completeness.

I suppose there is a theoretical possibility that a lab processing a DNA genealogy sample might attribute a sample to the wrong person, but there are careful safeguards against this and like Gadget I have not heard of it happening.
Title: Re: DNA Query
Post by: guest189040 on Monday 08 June 20 23:46 BST (UK)
If you have any other Cousins you could always buy them a DNA test, the results should help narrow down the answers.
Title: Re: DNA Query
Post by: MrsS2012 on Tuesday 09 June 20 09:43 BST (UK)
OK thank you for the replies everyone. I'll see what my cousin wants to do.