Understand shared cM

[ElizaMuza]

hello guys,

I have three different DNA Matches. With the first one I am sharing 26 cM and with her daughter 10cM, with the other DNA Match i am sharing 25 cM.
It says we are relatives 4-7 degrees, 4th Cousins. Which ancestor or greatgreat....parents are we sharing?

In this Case Match 1 is a daughter of a woman called Mary Smithers, Match 2 (her daughter) a granddaughter of Mary Smithers. Match 3 is a granddaughter of Harriet Smithers, a sister of Mary Smithers. So the Grandparents of Match 1 are the Greatgrandparents of Match 3. My possible 4x Greatgrandfather would be a brother of Grandfather of Match 1 and Greatgrandfather of Match 3.

The other scenario is that Match 1 is the Greatgranddaughter of a couple called Bennett/Coleman. Match 3 is a GreatGreatgranddaughter of the same couple. I would be a GreatGreatGreatGreatgranddaughter of the couple Bennett/Coleman. Are these relationships accurate for 4th Cousins? My ancestor was illegitimate so i can't say how i am related to the match but their families lived in the same village and down the road and the other branches of their tree does not match with my families location.

i hope you can understand my thinking and can help to understand my DNA Matches

[rsel]

Hi ElizaMuza,
     With those cM sizes you have a very wide range of relationships that are possible, so its difficult to say with any certainty.  I know it may fall outside the recommended cM sizez, but have you tried using the WATO tool on the DNAPainter web site ?  It allows you to enter a tree with a set of linked people and specify the cM match size to a target person, and then can suggest the most likely relationships between the target person and the tree you entered.

Richard

[Biggles50]

I agree with Richard, a wide range of possibles.

If you are having trouble getting your head around relationships based on cM values do look at DNA Painter’s Shared Matches tool and enter the cM value.  But before entering the cM value study the chart.

You will be presented with the probabilities after entering the cM value.

One can use the chart as a guide, the single figure in each cell shows the Mean value from within the range of values that the tool uses to determine probabilities.  The submitted cM values that they use in the tool are presented in the range of values which are under the single mean value.  The range if plotted in a graph would be a Bell Curve and you can use your matches cM to estimate where it would be on the Bell Curve and thus give yourself a better understanding of what the probability is likely to be.  Sorry if this is confusing, its the best I can do.