Recently I used the ‘DNAPainter‘ What Are the Odds Tool to place a DNA match in my tree and to identify her father.
M showed up in Greg’s list of matches at Ancestry.com. She and he shared 29 centimorgans of DNA across 2 segments, but she had no tree associated with her DNA. Her kit was administered by a 3rd person, D.
M and Greg’s shared matches were all cousins I knew, all of them associated with the Young branch of his tree. M also shared DNA with Greg’s Aunt Betty: 48 centimorgans across 4 segments. M and Aunt Betty had 14 shared matches. More than ten were known cousins all linked to the Young family tree.
I messaged D and she replied that M was born in outback Queensland and that M’s father was unknown. I knew of no relatives who came from there.
48 centimorgans of shared DNA is associated with a range of possible cousin relationships. It was not at all clear how M and Aunt Betty (and Greg) might be related.
I asked D to share a screenshot of M’s shared matches with Aunt Betty. I thought that if I knew how much DNA M shared with some of our known cousins I might be able to identify how M might be related.
One of the shared matches, that of J, jumped out. J is Greg’s 3rd cousin and is descended from one of the daughters of George Young and Caroline Young born Clarke. M and J share 815 centimorgans and so can be estimated to be 1st or 2nd cousins. Other known cousins also shared significant amounts of DNA with M, including F who shared 277 centimorgans and R who shared 443 centimorgans. Based on the amount of shared DNA F and R are estimated to be 2nd cousins to M.
I drew up a tree in the DNAPainter What Are The Odds tool, placing Betty and Greg and also J, F, R (and as well, K and B. I know how these are related.) K shares 60 centimorgans with M and B shares 55 centimorgans with M. Using the What Are The Odds tool you add how much DNA is shared between the match and the target name. The aim is to place the target on the tree.
I then switched to version 2
and then clicked on ‘suggest hypotheses’. The tool suggested 10.
Rachel lived from 1865 to 1918. M cannot be her child, so hypotheses 8 and 10 shown by the blue and green arrows are implausible. It is possible that M could be a grandchild of Rachel, but hypotheses 6 and 7, shown by the orange arrows, have much lower scores than other hypotheses, and so I removed them too. When removing hypothesis 8 though I did not delete that person on the tree but I removed the option that it was a hypothesis.
I am left with six hypotheses.
If I scroll down I get a ranking of hypotheses.
Scrolling further I get the table with a matrix showing the odds associated with each hypothesis and the various matches.
It can be seen that hypothesis 2 (highlighted in orange) is the most likely. J is most likely a first cousin of M, our target who we are trying to place on the tree. The next most likely hypothesis is that M is a half-aunt of J.
I know from my knowledge of the family tree that J does have a full uncle, brother of J’s parent M and showing as unknown sibling child of Leslie on the tree. Thus hypothesis 2 is possible from a genealogical perspective.
I checked the electoral rolls for the period that M was born and for the location. I found that the unknown sibling was indeed living in that part of Queensland at the relevant time. M’s mother had suggested the surname of M’s father. It was similar to the surname of J’s uncle.
On the basis of the calculations of What Are The Odds tool and a review of the broader circumstances, I am reasonably confident that hypothesis 2 is plausible. M is the 1st cousin of J. She is Greg’s 3rd cousin.