understanding Matches of matches knowing some connections

[brigidmac]

Using DNA painter tool  to theorise on possible relationships  from 3c to half c x3


can the possibilities be narrowed down by looking at shared matches to their known relatives ?

   X matches me by 54 cm
So there are several possibilities

I know what my relationships are  to our shared matches including several with private or unlinked trees.
So  I can make an educated guess at common ancestors


X has to work out the generation + which line they fit into

Does knowing that they match my own cousin( not theirs) by 121 narrow.down possibilities and eliminate some possible relationships

Can you see most likely relationship  * see charts below

[brigidmac]

X  me  54 cm & X  my cousin 121 cm 5 segs

Our  relationship to X must be the same !

We are similar ages to X but that is not always indication of DNA generations

What are the possible combinations now ?

[brigidmac]

I think it's odd that the top percentages of possible relationships suggested for me + X are the bottom most likely suggestions for
 X and my cousin

 #  I do  know  this person's DNA match amounts for my mum& my  mums cuz and half c1xR all descended from same grandfather .
 
Charts to follow

I'm  hoping these variations will help other people who DON'T know How they match

 So I'd  appreciate opinions from pro s or amateurs  about how /what to  deduce.
 
I think it already narrows down to 6 possibilities for X  and myself

Half 3C most likely from probabilities
Or 2C2R
3C ( most likely from generations)
Half 2C
2C 1R
Or  3C1R unlikeliest

[brigidmac]

So this is where I get stuck
How do we compare level of match between X myself .& my cousin as above

Or from chart below
 between X &  my mum 146cm 
X & mums  cousin 176cm

Can more possibilities be ruled out from this older generations matches

# Reworded to make  clearer ... hopefully !?

[brigidmac]

the top 5 suggestions would obviously be most likely and the older generation have more consistent probabilities for relationship matches

they MUST be a generation older than the first 2 examples

So some of the lower ones can be ruled out .

Need a logistics brain to confirm I'm thinking on right lines

I feel like the solution should be getting closer

Is the most likely answer now 3C to the sixties generation and 2C1R to the 1930s testees ??

If we have similar matches in future will we be able to extrapolate.

[brigidmac]

To continue in case anyone is following

Mr X has a high match with Mr T who has surname which is in our family (at first cousin level ) & matches son of Mr T at 381 cm

My mother matches Mr T at 146cm 2 segs
Who I  match at 38cm my cousin at 28cm

Theory was that Mr T and Mr X were the same generation and same relationship to us

Found that the connection was Mr Ts mother and surname a red herring  following the branch now  added to tree
Mr T is 2C 1R to my mum the cm levels are high for that level
3c to myself and MY cousin

Son of Mr T is showing as 3c1r to us and grandchildren of Mr t who have tested are not showing as matches  ..at 3c1r ..too distant

But they do match Mr X

Now think Mr X may be half nephew of Mr T

So if I could program all those results to a computer would it e able to confirm theory

[rsel]

Hi brigidmac,
   From your posts i am guessing you have used the Shared cM tool, on the DNA painter site, but have you tried the WATO tool ?  Using that, you can build a little tree  with you and your cousin, and enter the shared match to X for each of you, it can then use the combined odds to suggest possible relationships rather than just the one at a time ?

Richard

[Romilly]

I’ve tried using WATO Richard, but can’t make head or tail of the charts that I’ve done 😵‍💫

Romilly.

[rsel]

Hi Romilly,
   Which charts are you referring to ?  You have 3 parts to the results from the WATO tool, the tree itself which shows the various hypotheses (with v2 it also highights the best fit), then you get a table version of those hypotheses ordered by best fit to worst, with finally a table with the individual results from each person cM match.  I personally don't take to much notice of the last table, but the other 2 are very useful especially if you start removing the hypotheses you know are impossible :-) 

Richard