Methodologies for finding unknown ancestors

[SouthseaSteel]

I feel your pain!!  Despite understanding all the variables involved, I too feel there could be a robust methodology out there that systematically allows the user to either identify unknown DNA Matches or conversely to identify unknown ancestors in your tree.

I completely go along with everything else in this post, especially the Groupings discussion detailed in that classsic RC posting. And yes, multiple relationships/pedigree collapse is a real issue that should never be ignored. 

What is frustrating is that for me for the 15 or so DNA accounts I manage, most unexpected GGP identifications have just fallen into my lap fairly quickly based on Groupings analysis and a bit of triangulation and commonsense.  However, like the OPer, one unknown GGP for one account and for another account one Match of 136 cM remain stubbornly unresolved after 5 years.

All I can add here is to try the WATO tool.  It can help guide analysis, despite some extremely bizarre suggestions, but what never fails to be useful is the schematic tree of shared DNA Matches it presents after entering all your Match data.  It shows your inputted data as a pared down tree that ONLY shows your DNA Matches and the connections between them which I find extremely useful indeed. 

[Carmella]

This web article deals with small DNA clusters and small DNA matches in the UK (originally posted by another Rootschatter on another thread)  -

https://dna-sci.com/2023/05/04/working-with-junior-clusters-to-solve-unknown-parentage-in-the-uk/

[Zaphod99]

Be sure to get the latest edition of Bettinger's book. The first edition, which I've read many times, is already superseded a by later edition.

Zaph

Alas there is not a “one size fits all” solution.


Reading Graham Holton’s book will give you an insight into the technicalities, but be warned it is heavy going but it is the defacto standard, Blaine T Bettinger’s book is easier going.

[Steve3180]

Thank you one and all for your input.

I had a play with the WATO tool and I love the way it generates hypotheses but the results it gave me are wild. The first tree I tried it complained that there was nobody over 40 cM, I Wish !, in total on the maternal side I only have 11 dna matches over 40 cM, 8 of which are placed and only 1 in the unknown group. So I tried the tree with the Unknown at 56 cM, unfortunately sparser than the other, and as its most likely hypothesis it suggested 6 generations between 1874 and 1955, with lesser results even worse. I know a lot of people use this so I need to look at how best to present my data to it so I get sensible results.

The suggestion by Carmella was interesting also and possibly the most applicable as it was UK focused and understood that a lot fewer people test here. The chap who wrote it has a book out which I've just bought on Kindle but it's 500 pages so that might take a while to read.

I have a copy of "Genetic Genealogy in Practice" by Blaine Bettinger, which was useful originally but doesn't offer any help in this regard.

There's a new edition of the Graham Holton book out which I'm planning to get when they produce a Kindle version.

A few people mentioned drilling down to find candidates to test. Am I to understand you just find people who haven't tested but would likely be useful and write them a letter or something ? Does this actually get results ? I can't even get people who have already tested to reply !

I think in reality I'm just going to end up back at the waiting game as Biggles said. I've been at this five years now since the dna test, and fifteen before that and I thought I had enough, but it's not looking good.

[SouthseaSteel]

I notice that DNA Painter states in its WATO Q & A that "Strictly speaking, there is no minimum (for cM), but the statistics underlying WATO do not go below 40 cM, so the majority of your DNA matches should share at least 40 cM. The more they share, the better WATO works."

Not sure whether that means that such low cMs should not be entered in the first place as it may "distort" the hypotheses as experienced by you and me or whether they are simply redundant and are effectively ignored.

In my own frustrating case study I have 12 Shared Matches in my WATO but only 4 are over 40 cM and 2 of them are less than 50 cM.  The highest Match is only 136 cM.

[4b2]

I notice that DNA Painter states in its WATO Q & A that "Strictly speaking, there is no minimum (for cM), but the statistics underlying WATO do not go below 40 cM, so the majority of your DNA matches should share at least 40 cM. The more they share, the better WATO works."

Not sure whether that means that such low cMs should not be entered in the first place as it may "distort" the hypotheses as experienced by you and me or whether they are simply redundant and are effectively ignored.

In my own frustrating case study I have 12 Shared Matches in my WATO but only 4 are over 40 cM and 2 of them are less than 50 cM.  The highest Match is only 136 cM.

Is that not enough to get a good idea? From when I've used it, it seems to give quite good indications with such inputs.

I've also found it's best to just not put sub-40cM matches in - owing to them being to ambiguous to be useful.

[SouthseaSteel]

You know WATO is struggling when the highest hypothesis is weighted at 687,173.  Indeed, there are 52 hypotheses in total with no clear winner(s).  it is odd as the highest score suggested a Match 3 generations below, and it even strongly suggests that the Match could be 5 generations below.  And this is for somebody born in the 1970s!!!!

I will take out the sub 40 cM Matches and try it again.