Identifying someone with a really large DNA match

[Gadget]

are there any signs of you being related on more than one line?  I have quite a few as my father's side were in the same broad area for many years.

[TreeDigger]

Have you tried DNA Painter's WATO (What Are The Odds) tool? Because this sounds like a good case to try it with.

Just (well, it's some work) set up your tree with your 2x great-grandfather as starting point, list as many descendants and details as you can including for yourself, then add the cM amounts for X, pose the question "where do I fit in" with X's year of birth, and hit enter.

You should get a number of hypotheses and at least an idea where to look.

TD

[LizzieL]

Tried WATO but doesn't seem to get me much further. Implies that our closest shared relative would be my paternal grandfather, but with such a large match, that was my guess too.

[TreeDigger]

I ran WATO's beta tool with your data, entering hypothetical birth years based on your information. It really throws up some shade, because really none of the hypotheses make sense genealogy wise. Of course adding birth & death years greatly improves statistical calculations.

Have you removed all the hypotheses that would be impossible (i.e. placing X in your own age group) and seen significant percentage increases? Because I did, and though age wise it's still off, I think you have to start looking for an unknown (half) sibling of your father.

Somehow I have the sneaking suspicion you already know that though 

[Biggles50]

I agree with Treedigger.

665.7cM is to close a relationship.

WATO does seem to use the “Unknown” option rather a lot, its there “get out of jail” card.

It looks to me like the match is probably a 1/2N or 1/2GN.

I certainly would not discount the 56% batch, one of my 2C is 32 years my senior.

I very much doubt if documentation will tell the right story, Mother’s Maiden name of their birth cert is probably all there is.

Bite the bullet and try to contact them.

[LizzieL]

I have tried to contact, but I am not a subscriber to MH, just uploaded data (and possibly paid a small amount at the time), so I would have to take out a sub.
Looking at Birth registrations for people with the same name born in the year stated on his tree, there are only two. One is on Facebook, but hasn't been active for just over a year. Given age, probably abandoned FB as it's only for oldies  . But there doesn't seem to be a family resemblance. But he is the most likely geographically. The other one lives further from my target area and I have found his parents names, but haven't yet got back any further with him.

If it was a half nephew or half great nephew, that would mean descended from an unknown child of my father. But that is impossible because there is no match at all with anyone connected to my paternal grand mother's side and I have a number of matches on that side on MH, both from her father's and her mother's side. 

[Nanna52]

Take a breath Lizzie.  Have you worked out broadly which side he belongs to, paternal or maternal.
My 4 half first cousins match me at 572, 514, 496 and 483, all on ancestry.  Same grandmother, different grandfathers.  From experience I know that numbers on My Heritage are bigger than on Ancestry so half first cousin would be reasonable to me.
It is a pain that you can’t email my heritage matches.  I suggest to look carefully and see if you can build or extend a tree.  Mind you finding the male responsible is a hard job, especially as in my case there were 5 possible brothers living in the area at time of conception.   

Added: don’t discount any on looks.  I look nothing like any of my half first cousins.

[LizzieL]

See my original post and WATO diagram

I can see from shared matches that he would be related to my paternal grandfather's mother's line, so that excludes the only first cousins who could have a child in their 20s - they're on maternal side.

Definitely no matches whatsoever with any of my mother's side and no matches with my paternal grandmother's line. Only my paternal grandfather's. All the matches trace back to my father's paternal grandmother's line.
As well as MH matches, I have some who I have pasted in to the Chromosome browser on DNA painter who have uploaded to GEDmatch, principally son and cousins of K (see WATO diagram). That line was very prolific. All point to my 2 x great grandparents as being CA's but from the magnitude of the match not the closest.

[Cell]

 I share  over 500 cm with my first half cousin .
 I wouldn't totally  rule that age gap of you being 70 yrs old and your match being 20yrs old  for being a half first cousins .

Many people  when filling  out  the info when uploading  DNA don't put their  real  ages in

you can also  also alter your  original   details  attached to the dna., I recently  altered my child's as he was showing  over  20 or something (  he's not  over 20  he's actually years younger)  but  I didn't  like him  being over 20 lol  , so went into settings and altered  our original  made up details.

I think  anyone  signing  up with real details    must be totally  mad. Do not go by their about age on their profiles on myheritage ,  why do you  think  your  match  is 20 years old?  Is it just  because  their profile says  20 years  and under?

I know  mine  is way off  , I am under
20  on myheritage  lol  ( I  am not lol)  because  I on purposely  put a wrong  age for myself  when  I uploaded  to myheritage.

Your match  could be any age, maybe they're not 20, and they're nearer your age
Ignore  ages  on  their profile.
I have  a totally made up age on my heritageDNA  by a couple of decades.   ( and I have  no tree there either.


 Very Kind regards