Ancestry DNA. Is there any possible way this is my 1st cousin?

Anonymous 1

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For all my life I have known this person as my 1st cousin... Our dads are brothers (same Grandparents) , there has never been a question about it. We both took DNA tests and this is what I am getting in relationships for her.

Shared DNA: 77 cM across 6 segments

Unweighted shared DNA: 80 cM

Longest segment: 28 cM

3rd/4th cousins.



Both lines of my family are very intertwined way back when. So this cousin shows up related to random people in my moms and dads side but not to my closely related family.



She is my cousin regardless, but is there any way at all she is really my 1st cousin?
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Aletheia
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Anonymous 1 wrote: Tue Jun 28, 2022 3:35 pm Shared DNA: 77 cM across 6 segments
Unweighted shared DNA: 80 cM
Longest segment: 28 cM
https://www.familysearch.org/en/blog/ce ... anding-dna
https://whoareyoumadeof.com/blog/what-i ... -ancestry/
https://familytreemagazine.com/dna/how- ... tionships/

Image

Note that a given relationship, such as first cousins, can share varying amounts of DNA because of recombination (“shuffling” that occurs at conception). You usually share about 850 cM with a first cousin, but that number could be as low as 553 or as high as 1,225 cM.
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Aletheia
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Anonymous 1 wrote: Tue Jun 28, 2022 3:35 pm is there any way at all she is really my 1st cousin?
I think the word you want is "genetically", rather than "really".

In the sense that genetic 1st cousins share exactly one grandparent...

...there's always a chance of samples being swapped or contaminated, or the company screwing up.

But, unless you're trying to work out whether it is safe for the two of you to have S*x (or for your children to do so). Or trying to work out if your grandmother had an affair...

does it really matter?
Anonymous 2

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First cousins should share a set of grandparents, no?
Aletheia wrote: Wed Jun 29, 2022 5:01 am
Anonymous 1 wrote: Tue Jun 28, 2022 3:35 pm is there any way at all she is really my 1st cousin?
I think the word you want is "genetically", rather than "really".

In the sense that genetic 1st cousins share exactly one grandparent...

...there's always a chance of samples being swapped or contaminated, or the company screwing up.

But, unless you're trying to work out whether it is safe for the two of you to have S*x (or for your children to do so). Or trying to work out if your grandmother had an affair...

does it really matter?
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carterscutie85
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Anonymous 2 wrote: Wed Jun 29, 2022 5:10 am First cousins should share a set of grandparents, no?
Aletheia wrote: Wed Jun 29, 2022 5:01 am
Anonymous 1 wrote: Tue Jun 28, 2022 3:35 pm is there any way at all she is really my 1st cousin?
I think the word you want is "genetically", rather than "really".

In the sense that genetic 1st cousins share exactly one grandparent...

...there's always a chance of samples being swapped or contaminated, or the company screwing up.

But, unless you're trying to work out whether it is safe for the two of you to have S*x (or for your children to do so). Or trying to work out if your grandmother had an affair...

does it really matter?
I was coming to say that lol. My aunt's child certainly has the same paternal grandparents that I do.
Anonymous 1

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Aletheia wrote: Wed Jun 29, 2022 5:01 am
Anonymous 1 wrote: Tue Jun 28, 2022 3:35 pm is there any way at all she is really my 1st cousin?
I think the word you want is "genetically", rather than "really".

In the sense that genetic 1st cousins share exactly one grandparent...

...there's always a chance of samples being swapped or contaminated, or the company screwing up.

But, unless you're trying to work out whether it is safe for the two of you to have S*x (or for your children to do so). Or trying to work out if your grandmother had an affair...

does it really matter?
In the sense that she is still my cousin, no it doesn't matter.

As for genealogy yes it does.

And if we are genetically 1st cousins then we would share a set of grandparents (our dad's parents)
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Aletheia
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Anonymous 2 wrote: Wed Jun 29, 2022 5:10 am First cousins should share a set of grandparents, no?
Yep. My screw up!
Anonymous 3

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She’s not your first cousin.
PrincessLaLa
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Is there any chance that one of you is adopted? Maybe born to another family member but raised by who you know as your parents?
Based on the numbers you gave, the two of you are not biologically first cousins. There could be a few different reasons (possible relationships) for the results you ended up with though.
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PrincessLaLa wrote: Thu Jun 30, 2022 9:52 am Is there any chance that one of you is adopted? Maybe born to another family member but raised by who you know as your parents?
Based on the numbers you gave, the two of you are not biologically first cousins. There could be a few different reasons (possible relationships) for the results you ended up with though.
No, neither one of us is adopted. All my relationships came out as expected DNA wise (Minus this cousin). I called my mom and asked (didn't want to ask cousin, her mom or my uncle) and my mom knows that my cousins mom was 18 pregnant and gave birth to my cousin, but seemed shocked with the results... So if something did happen and my uncle is not her father, my mom had NO idea.

The weird thing the more I look. This cousin is related to bits and pieces of my moms family and my dad's Paternal side (My mom and dad's lines intermix generations back so everyone matches everyone somewhere) . But nowhere does she show matches to my dad's moms line.

So as far as I can see there is 2 options here. My uncle is not her dad and I am related to her mom many many generations back (this makes the most sense to me.) OR my uncle is not my grandparents kid, and he is a interfamily adoption from my grandpa's family (If this is true, I can't figure out how and grandma and grandpa are gone).

It's not going to change anything, and I am not going to ask her. She knows I do family history and have done the ancestry DNA test. If she wants to tell me she will. It just seems so weird to me, and I was hoping that it might just be a weird DNA fluke or something.
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