Autosomal DNA 1st cousin mystery

Genetic genealogy is the application of genetics to traditional genealogy. Genetic genealogy involves the use of genealogical DNA testing to determine the level and type of the genetic relationship between individuals.
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MarcuccioV
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Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

There HAS to be someone on here with enough experience in Autosomal DNA testing to POSSIBLY explain this (doesn't seem to be much explanation on the web):

On my Ancestry.com DNA matches list, I have TWO people who come up as FIRST COUSINS to me.

Cousin #1 is a known first cousin, the eldest son of my father’s older brother. We know each other well. He matches me at a level of 1,212 cM (17% match) on 33 segments with a longest match being 130cM.

Since he matches me on my paternal side, he shows NO Italian ethnicity.

Cousin #2 is an enigma. I have never heard of her before. We have been in contact, but can’t make any headway into the potential relationship. There ARE some oddities though, which make it all the more mysterious and confusing.

She matches me at the level of 838cM (12% match) on 38 segments with longest match at 75cM.

That puts her squarely in 1st cousin territory. She indicates we are very close in age (ruling out a possible 1st cousin 1x removed). She was also born in Southern California, as was I. She claims she was NOT adopted.

She has a public tree, which I have researched. Only match found is we appear to share a common ancestor – a 5GGf on my paternal side, who is a 6GGf on her maternal.

Her ethnic makeup is 50% Italian (again, as am I). But on HER tree, NO Italian surnames (at least none that can be determined). She IS at least, interested in this Italian ethnicity.

When we compare shared matches, it gets EVEN MORE bizarre.

ALL of our shared matches have at least a decent % of Italian (2 of those are 98% and I have connected the dots to my maternal side). When I listed family surnames on the Italian side, she had never heard of any of them before.

She also DOES NOT match my paternal first cousin, nor any of my paternal 2nd-3rd-4th cousins either. I think that rules out the paternal side of the family. Right..?

So as a 1st cousin (remember I ruled out 1st 1x removed due to age), that makes the ONLY possible relative my maternal uncle (my mother’s twin brother). Okay, so her age fits in the middle of the 9-year gap in ages between 2 of his kids (born 6 years before me & 3 years after).

But it seems remote (nearly impossible) at best. And she claims no adoption (I don’t suppose illegitimacy can be ruled out, but I just can’t make that work out). I don’t recognize her mother’s name, plus it’s her maternal side where I found my paternal ancestor match.

NONE of this makes the least bit of sense to me, and I'm a “rational” type of thinker (as opposed to “emotional”). Call me Mr Spock (I find the circumstances illogical, Captain).

Is there ANY chance this is some kind of fluke..? But then why connections to my maternal relatives..?
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Re: Autosomal DNA 1st cousin mystery

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As I noted to you, lot's of possibilities but the obvious on cM of match is what I think it may be, but note the possibilities in the table I showed earlier. 1st cousin range can also mean other relatives as well.

If you can get her to do a 23andme kit, then connect with you, you might see a better connection. 23andme is more accurate than Ancestry and also they let you see more details and also DNA to DNA testing company, results will shift higher or lower.

Also check your 23andme matches to see if it shows any X chromosome matches like mine below. This might be because I tested my Mother and it allows it to denote a match. It automatically tells me if we share a maternal grandparent, in this case we do, same maternal GGPs
match23.PNG
You could ask her to upload to gedmatch or myheritage then do a comparison, myheritage will show you the chromosome browser for the ancestry data.
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

afecad wrote: 15 Apr 2021, 01:58 As I noted to you, lot's of possibilities but the obvious on cM of match is what I think it may be, but note the possibilities in the table I showed earlier. 1st cousin range can also mean other relatives as well.

If you can get her to do a 23andme kit, then connect with you, you might see a better connection. 23andme is more accurate than Ancestry and also they let you see more details and also DNA to DNA testing company, results will shift higher or lower.

Also check your 23andme matches to see if it shows any X chromosome matches like mine below. This might be because I tested my Mother and it allows it to denote a match. It automatically tells me if we share a maternal grandparent, in this case we do, same maternal GGPs

match23.PNG

You could ask her to upload to gedmatch or myheritage then do a comparison, myheritage will show you the chromosome browser for the ancestry data.
Yes, I've thought of these things, but I think this is all new to her and I don't want to burn any of the bridges I've crossed thus far. I may just wait to see if she comes around & seems more willing to explore the connection. I don't want to risk alienating her at this point...
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Re: Autosomal DNA 1st cousin mystery

Post by afecad »

At this point, I'd suggest you post your question on one of the forums where there is more DNA aficionados. There are others too, but this is enough to get you started and they are very active with people who can likely give you more opinions.

https://forums.familytreedna.com/

https://customercare.23andme.com/hc/en- ... mer-Forums
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

afecad wrote: 15 Apr 2021, 04:06 At this point, I'd suggest you post your question on one of the forums where there is more DNA aficionados. There are others too, but this is enough to get you started and they are very active with people who can likely give you more opinions.

https://forums.familytreedna.com/

https://customercare.23andme.com/hc/en- ... mer-Forums
Okay, I will. Thanks. 8)
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Re: Autosomal DNA 1st cousin mystery

Post by darkerhorse »

I think it's a good idea to attract responses from others on all the related threads you've started. Someone new may have some new insights.
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

darkerhorse wrote: 15 Apr 2021, 21:32 I think it's a good idea to attract responses from others on all the related threads you've started. Someone new may have some new insights.
I will certainly take it under advisement.
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

So I've done a little more research into this. Based on documents posted by her, her mother wasn't exactly stable, relationship-wise. She was married at least 4 times, the first time when she was very young, and divorced 3 times. I also checked into other possible family members and the relationship comes down to only ONE possible match -- her father CANNOT be anyone but my mother's twin brother (albeit the odds seem astronomical).

Since my last post, my wife received the results on her test, and I checked some of her 1st cousin matches for comparison. Although still in 1st cousin range, her matches (documented and known relatives) are weaker than my match to my "mystery" cousin. Only my known 2 first cousins are stronger matches, but that's relative. Point is, it's not a mistake or miscalculation.

And there is NO possibility of her being a 1st-once-removed. 0%.

While looking for information on my matches' mother, I believe I stumbled upon her husband's profile. It shows a pic of a man and woman (fairly recent pic) in wedding garb. The woman looks to be about my age, dark-haired.

I studied the pic closely. Although not necessarily striking, I see a slight resemblance to my uncle's 3 daughters (she would be a half-sister to them). She does NOT resemble my dad's side at all. Not definitive, but it could be a further clue.

Since our last communication, she has been off the radar. Perhaps this whole sordid mess is sinking in and she needs time to process it all. I can't imagine the feelings of betrayal. I'm going to give her all the space she needs, since I am at least confident that I have solved the mystery...
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Re: Autosomal DNA 1st cousin mystery

Post by darkerhorse »

I've lost track. Can you briefly summarize the mystery and the solution?
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

darkerhorse wrote: 18 Apr 2021, 18:28 I've lost track. Can you briefly summarize the mystery and the solution?
My ancestry matches gave me 2 1st cousins. One is a documented paternal male cousin that I know personally.

The other was a female 1st cousin I had never heard of. Her ethnic makeup is 50% Italian (as is mine). She has a public tree, with no Italian surnames. There IS, however, a supposed match between her 6GGf on her maternal side & my 5GGf on my paternal.

Her DNA is NOT a match to the male paternal 1st cousin above. She has 5 shared DNA matches with me -- all with some % of Italian ancestry. 2 of those are 98 & 97% Italian, and who I've connected the dots to my maternal (Italian) grandparents.

Being a first cousin, and since none of my cousins were old enough at the time to give birth (she & I are close in age). That means one of her parents MUST be a sibling of one of MY parents.

Since she doesn't match the paternal 1st cousin, but matches others tied to my maternal side, that leaves a sibling of my mother. She had one who reached adulthood. Her twin brother.

"Mystery cousin" was born & raised here in Los Angeles, as was I. My uncle lived here from 1953 until his death in 1997. He can be the only possible match as her parent.

I have been in contact with her, but she is careful with information (I can understand). She says she is NOT adopted. She refers, however to her mom as her "birth mother". Her mom has a checkered history where marriages & relationships are concerned.

So I found (through my own research) a photo of what I believe is her (I'm pretty sure it is). Take a look at the following photos. The first is "mystery cousin" (mother NOT Italian). The second is one of my known 1st cousins (daughter of the same uncle, mother is Sicilian). Tell me if YOU see any resemblance:
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

Let me just add that 'mystery cousin" looks more like my actual known cousin than her own sisters do. And my known cousin's eyebrows are her mother's. Mystery cousin's eyes/eyebrows look like my mom's side...
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Re: Autosomal DNA 1st cousin mystery

Post by MarcuccioV »

And this is my uncle (he and my mom looked nothing alike):
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Re: Autosomal DNA 1st cousin mystery

Post by darkerhorse »

Yes, some similarity in facial features and expressions. If you had said they were sisters I would notice their coloring is a bit different, but I wouldn't have been surprised.

So, you never knew of her because of some intrigue?
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Re: Autosomal DNA 1st cousin mystery

Post by darkerhorse »

You also could use the face comparison software.
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Re: Autosomal DNA 1st cousin mystery

Post by darkerhorse »

*photo comparison software
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