View Full Version : DNA Mystery

13-09-2018, 4:29 PM
I am having more and more problems with sorting out my DNA Matches. This is what I have/know.

I share 226.7cM of DNA with Match 1
I share 203.5cM of DNA with Match 2
I share 18.7cM of DNA with Match 3

Match 1 and Match 2 share 336.8 cM, and Match 3 is Match 1's Grandparent and they share 1782.6 cM. I can see the relationship between matches 1 and 2 on their trees, however, I can't find a link between me and any of them. Am I wrong in thinking that if I match 1 you would expect the match to her grandmother to be higher?

Please if anyone can suggest a way of getting to the bottom of this I would be very grateful.

Thank you.

14-09-2018, 5:45 PM
My thoughts are that I would want to see and compare all these matches on a chromosome browser, which would show if the 18.7 cm you share with the grandmother of match 1 (which I presume is one single length) is also shared at the same place on the same chromosome with the other two matches.

Are match 1 and match 2 also descendants of the husband of match 3? That could suggest that you are also related to him, or related to one of his and match 3's joint children.

If there is a Jewish element you could easily be related to multiple ancestors of all three matches. Hegemony / cousin marriage in the Jewish community makes unravelling relationships very tricky.


15-09-2018, 7:40 PM
Hi Deeny, Thanks for your reply. I have looked at the the three matches on a Chromosome Browser and the 18.7 cM of match 3 do not match with any of the cM from Matches 1 and 2, and you are right it is just one length.


This is how the matches sit on one tree, but I don't match at all as far as I can see.

16-09-2018, 9:40 PM
It seems, from your chart, that you are related to Match 1 as well as to Match 3, her grandmother, but you have inherited the same 18.7 cM segment of DNA as the grandmother through an entirely separate line. You are related to Match 1 in two separate ways, so from two different lines of their family, even though Match 1 hasn't inherited that particular 18.7 cM length of DNA.

From your chart you can see how Match 1 and Match 2 are both descended from EK and DP so the DNA that they share will have filtered down through one or both of them, from the previous generation which includes HK, HP, EP and AS on your chart. The DNA you share with Match 1 and Match 2 is likely to have come down to you from one or more of those four, (or from their parents) or a sibling of one of those four (or their parents).

The grandmother's 18.7 cM match with you comes from somewhere within her own grandparents' lines of RT, JM, ER and FR or their parents, or siblings of those people.

You may have to build your matches tree back another couple of generations before you can find the mutual ancestors you have in common on both lines and just hope that there hasn't been an NPE along the way to throw everything awry!