DNA Query

[Gadget]

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.

[MrsS2012]

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 

[MrsS2012]

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?

[Gadget]

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 

[avm228]

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.

[MrsS2012]

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.

[Gadget]

I've not known such a mistake.

[MrsS2012]

I've not known such a mistake.

OK thank you... Awkward situation.. I'll let her decide how she wants to proceed.

[avm228]

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.