Common Ancestor hints.

[brigidmac]

George  if You mean they don't show up as having a common ancestor ?

If an ancestor is illigitimate you can add the mother's name and a father as unknown then add the surnames of the common ancestor of those 4  people  tag as hypothesis
How close are the matches to him ?
 
 deduction suppositions  + calculations can add to luck of finding matches .
Also can be worth contacting DNA matches and ask if they know how they match !

[George52]

Hi brigidmac, thanks for your reply. F-I-L was adopted and we have his birth mothers name but not his fathers (and adoption records cannot be located which might have helped with some back story). The 2nd to 3rd matches we do have in our tree and are in contact with them but no luck so far.

Two of the most closest matches are on MyHeritage, one was also adopted at birth and the other has no information to share. They are also added in to the tree.

For the Ancestry matches they are 228cM down to 122cM. We also have a match at 225cM who is not in that same family who is non responsive to messages.

For the MyHeritage matches we have a 346cM (also an adoptee) and a 227cM (who has no information to share).

We've added everyone that can be added and also researched their lines, but no breakthrough's so far. I was just a bit surprised that not even one person on the potential birth fathers side is showing as a common ancestor.

[brigidmac]

I don't think they can show as a common ancestor if the other people haven't added a potential line to their trees . But hopefully a mutual link will show up in future . Good luck