DNA Mystery - Please Help

[cmower]

My mother, her sister, one of my sister's, one of my brother's and I all had our DNA tested.  Individual A showed up as a possible 3rd cousin (mother's side) to me, so I compared A to myself and all my relatives mentioned above.  I show up with 8 segments matching A, my sister and brother match 7 segments, my mom matches 1 segment and my aunt matches no segments.  Results for cM were similar.  I know nothing about DNA, but it doesn't seem logical to me that my mom would have fewer segments matching A than would my siblings and I.  And my aunt has none.  Wouldn't he have had to inherit the DNA from her if it was on her side?  My father died, so we can't have his DNA tested, but I'm thinking my father would have had more segments matching and that's why we have more segments matching than our mom.  Does that seem likely?  If so, does it also seem likely that somewhere way back, my mom and dad shared ancestors?

[davidft]

Hi

You have not really given enough information there. It is important to know the size of each match as if the match is too small it might be a false positive. As your mother and your aunt only have one segment matching between them I am curious how you "know" the match is on your mother's side, what you are seeing there could be a false positive.

If you could give details of the sizes of the matches someone else may be able to help (I am going to bed now). It would also be helpful if you gave your reasons for thinking the match is on your maternal side. Also what company did the tests.

Good luck.

[cmower]

davidft - Thanks for the reply.  I have no idea what I'm doing here.  The testing was through 23 and me and they are the ones that indicated the match was from my mother's side.  I suspect that to be due to the fact that there was some match on my mother's side.  I failed to mention earlier that my son was also tested.  Here are all of the results of the match to A:

My mother - 6 cM / 1 segment
My mother's sister - 0 cM / 0 segment
My sister - 82 cM / 7 segments
My brother - 127 cM / 7 segments
Me - 113 cM / 8 segments
My son - 76 cM / 5 segments

Please let me know if there's something I'm leaving out.

[Rosinish]

My mother - 6 cM / 1 segment
My mother's sister - 0 cM / 0 segment

I know nothing of DNA either but that looks odd.

What's the match like with your mother & her sister as well as the rest of you?

Your brother's seems high for being a maternal match with so many females in the loop or am I seeing things wrong with my non experience?

Annie

[sugarfizzle]

First of all, a warm welcome to Rootschat, and this board in particular.

It doesn't seem likely that the match is a maternal one. Have you tried contacting the match, to see if they know anything?

My suggestion would be to try that first, if you haven't already. If no response or no connection found, it may be a waiting game to see what other matches turn up.

Perhaps you could afford to test at ancestry as well, or your mother plus at least one of her children.  Ancestry not only has a much larger database, it also has the benefit of the associated family trees.

I have no experience of 23andme, so I don't know how best to advise you to sort through your matches there. At ancestry it would be probably be very clear, very quickly, whether your matches are on your father's side or on your mother's side, due to shared matches and matching tree names.

Regards Margaret

[whiteout7]

Looking at this DNA tool it doesn't seem mysterious to me

https://dnapainter.com/tools/sharedcm

[sugarfizzle]

Looking at this DNA tool it doesn't seem mysterious to me

https://dnapainter.com/tools/sharedcm

cmower has been predicted as 3rd cousin to this match by 23andme.
Possibly his mother has been predicted as 5th to 8th cousin (based on ancestry, don't know what terms they use at 23andme).

These roughly relate as predicted by DNA painter - though other relationships are included for 113 cM and 127 cM, they are of the same sort of degree.

6 cM
63.72% 6C 6C1R 5C 6C2R 4C1R 5C1R 7C Half 3C2R 4C2R 5C2R 7C1R 3C3R 4C3R 5C3R 8C or more distant

113 cm
42.54% Half 2C 2C1R Half 1C2R 1C3R 28.23% 3C Half 2C1R 2C2R Half 1C3R

The mystery is in why the disparity.

Regards Margaret

[cmower]

Thank you all for your responses.  I wasn't aware of that DNA tool, so that should prove to be very helpful.  I still don't understand why my mom would be a more distant relative than my siblings and I, but am beginning to really lean toward thinking the closer relationship is coming from my dad's side and there's some sort of distant relationship between my parents.  Both had family members who lived in County Armagh, Ireland.  Maybe I could get some cousins from my dad's side to get tested.  Maybe that could shed some light on the subject?

[davidft]

Thank you all for your responses.  I wasn't aware of that DNA tool, so that should prove to be very helpful.  I still don't understand why my mom would be a more distant relative than my siblings and I, but am beginning to really lean toward thinking the closer relationship is coming from my dad's side and there's some sort of distant relationship between my parents.  Both had family members who lived in County Armagh, Ireland.  Maybe I could get some cousins from my dad's side to get tested.  Maybe that could shed some light on the subject?

Pretty much agree with all that

Yes I would question 23andme's assertion that it is a maternal match, the amount of cMs your mother shares is too low. Most sites don't use matches under 7 or 10 cMs as the chance of a false positive is too high and I think that is what you have with your mother's results

Testing a paternal cousin would be a good idea as it could confirm what you have is actually a paternal match. (Provided any matching segments are sufficiently large).

This thread
https://www.rootschat.com/forum/index.php?topic=808674.0
has a couple of articles where a parent supposedly has less of a DNA match than their child and explains what may actually be happening there.

It would be a good idea to contact person A and ask if they want to try and discover the match. However you would need to know your ancestors back to GG Grandparents and  person A the same or it could get difficult. Rememner not everyone replies and some people take a very long time to reply so my advice would be to not put too much detail into the invitation and hope that the curiosity you stirred in them prompts them to reply.

Good luck