What's the largest cM DNA match you have where you can't identify the link?

[IgorStrav]

I helped someone who was adopted and they have the non-biological tree attached to their DNA results and no indication that it is not their genetic family. This would make it impossible to understand, though experienced researchers would question the shared matches against the tree.

Quite understandable they'd add their 'family' but 'wrong' tree to the DNA results.
As you say, confusing for inexperienced matches.

[IJDisney]

I helped someone who was adopted and they have the non-biological tree attached to their DNA results and no indication that it is not their genetic family. This would make it impossible to understand, though experienced researchers would question the shared matches against the tree.

This is a good lesson in why you should not just appropriate a bunch of names because Ancestry says you are related, and should always contact (or try to contact) the creators of those genealogies first.

[Jill Eaton]

I have a 200cm match, a 182cm match and a 166cm none of whom I can place.

They either have no trees, trees with only a few ancestors  - whose names I can't trace, or an unlinked tree and when contacted, say "Oh yes. I have that name in my tree too" but give no other details and don't share their tree. Any matches with very high amounts of Cms are close family who have taken my tree and done no research of their own.

I have 4 x 2nd gt grandparents that are either anonymous, fictitious or have no clear information to follow to allow a definite identification.

I find it enormously frustrating knowing that someone who shares some of my DNA might have the answer to my brick walls

Certain surnames not in my tree do crop up on some of my lower match - Wheeler, being one of them, but as yet I can't find where, or even if, that name has any relevance to my family.

[Jo6100]

My husband’s dna came up with a probable first cousin at 801 cm/ 40 segments plus SEVEN 1st-3rd cousins sharing between 254 and 498 cm!  They are all shared matches with each other. There are several around 180 cm as well, all shared. They seem to share the same grandfather/ great grandfather ( depending on generation). One of the profile pictures looks startlingly like my brother in law.  There are no shared ancestors although some do share our home town. Two of these cousins are actively looking for the link. Someone seems to have played away but I can’t figure out who. There are no illegitimate births that I can see. The only match to my husband’s surname is 7 cm which I gather could be “noise”. It’s not a very common surname so I don’t know if it just means none of his paternal relatives have tested. There are some very distant matches with some of the names of his paternal great and g g grandmothers so I’m a bit stumped.

[IgorStrav]

My husband’s dna came up with a probable first cousin at 801 cm/ 40 segments plus SEVEN 1st-3rd cousins sharing between 254 and 498 cm!  They are all shared matches with each other. There are several around 180 cm as well, all shared. They seem to share the same grandfather/ great grandfather ( depending on generation). One of the profile pictures looks startlingly like my brother in law.  There are no shared ancestors although some do share our home town. Two of these cousins are actively looking for the link. Someone seems to have played away but I can’t figure out who. There are no illegitimate births that I can see. The only match to my husband’s surname is 7 cm which I gather could be “noise”. It’s not a very common surname so I don’t know if it just means none of his paternal relatives have tested. There are some very distant matches with some of the names of his paternal great and g g grandmothers so I’m a bit stumped.

Good grief.

Well if none of the names match it certainly seems as if there is what I understand is called a NPE.  Or 'playing away' as you say.

At least some of these matches are trying to find out where the event happened, rather than just letting it remain a mystery.

I would be very spooked to find a family likeness with someone I'd no idea how I was connected to!

[JaneyH_104]

I can completely relate to the frustrations here.

My top match (121cM) and 3rd highest match (97cM) both live in the USA and were born there, as were their parents. Having done some auto-clusters, I now have a private/unsearchable tree for them which includes these two plus three other matches. I know how these five are all related to each other, just not how they relate to me.

With the help of one of these matches I’ve built out their tree to their first emigrant ancestor, who arrived in the USA in 1869 but previously lived in Huddersfield in Yorkshire. Now, my Dad’s paternal line all come from ... Huddersfield. What’s more, my great-grandfather was illegitimate. Coincidentally - or perhaps not - he was born in late 1869.

My working theory is that JT got my 2GGM pregnant and then skipped the country. She had been estranged from her husband for some time (or he may have died, although I’ve yet to find a suitable death record). This relationship is within the bounds of possibilities in terms of shared cM, but I need more testers on my side I think ...

[IgorStrav]

I can completely relate to the frustrations here.

My top match (121cM) and 3rd highest match (97cM) both live in the USA and were born there, as were their parents. Having done some auto-clusters, I now have a private/unsearchable tree for them which includes these two plus three other matches. I know how these five are all related to each other, just not how they relate to me.

With the help of one of these matches I’ve built out their tree to their first emigrant ancestor, who arrived in the USA in 1869 but previously lived in Huddersfield in Yorkshire. Now, my Dad’s paternal line all come from ... Huddersfield. What’s more, my great-grandfather was illegitimate. Coincidentally - or perhaps not - he was born in late 1869.

My working theory is that JT got my 2GGM pregnant and then skipped the country. She had been estranged from her husband for some time (or he may have died, although I’ve yet to find a suitable death record). This relationship is within the bounds of possibilities in terms of shared cM, but I need more testers on my side I think ...

Fantastic detective work......and a tantalising possibility.

Whilst at times frustrating, it's true that DNA now gives us the opportunity to solve the problems which otherwise would have remained a mystery forever.

I can't be the only one to have family history mysteries that I can't believe I'll never solve - though in all likelihood mostly I never will.

[JaneyH_104]

Even more tantalising is the prospect of being able to extract viable DNA samples from objects such as stamps and envelopes. I have a letter sent from my GGF to my GF in the early 1930s. A positive result from this would prove or disprove my theory, I’m sure.

I’ve read somewhere that the first commercially available tests of this type could be available within a year!

[Craclyn]

Testing of artefacts is already commercially available, but is currently expensive.