Mystery Matches: Who are they and how are we related?

Identifying Mystery Matches

  • Being able to view a DNA Match’s tree is key to working out how the two of you are related.  If you don’t have a subscription/free trial to Ancestry, you will only be able to view trees if the owner sends you an invitation.
  • You are likely to find that many of your matches either have no tree at all, or a very small tree full of living people, which can be very frustrating!  However, there is nothing to stop you from building trees for your matches.
  • Being able to find enough information to start with can be difficult, but the YouTube videos below offer some great ideas:
A DNA Match with No Tree? No Problem! – Lisa Louise Cooke and Diahan Southard
Building Quick & Dirty Trees to Identify Genetic Matches – Blaine Bettinger

To find clues to start a tree for your Match:

If your Match has a small tree…

  • Even if their tree is tiny – perhaps it only has four people and three of them are living – don’t give up on it!  View their tree and look at the name they have given their tree – that may give you a very small clue.
  • Use the Shared cM Project Tool: to identify possible relationships between you and your match.  Now estimate how many generations you would need to go back to find a Common Ancestor.  
  • For example… You share 125 cM with a match:
  • You can tell from their profile page/tree that you are about the same age
  • The suggested relationships for 125 cM are roughly around third cousin level
  • Third cousins would share a set of Great-Great-Grandparents
  • If you were working on a potential 3rd cousin match, you might need to build a tree that contained all these ancestors (and maybe another generation too) before finding your Common Ancestors:
  • Tree-building can be very time-consuming but the more trees you build, the more connections you should find.

If your Match has a no tree…

Can you work out who they are and create a Floating Branch for them?

Look at their Ancestry profile page:   

  • Some people supply additional information about their family on their profile, or may have filled in details of their age or where they live.

Check Ancestry’s message boards to see if they have ever posted anything that mentions their ancestors:

  • On the black bar at the top of the screen, click on Help, then Message Boards and click Advanced Search.
  • Enter the name of your Match in the Author of Message field and click Search.

Does the match have a Username?

  • If your match has a username you may still be able to work out who they are – people often keep the same username on all the sites they visit.  People Search Sites can be helpful (especially if you are searching for people in America):

Try Social Media

  • If you can’t find them on Facebook try Instagram, Twitter and Pinterest.

Try Google

  • Perhaps they have a tree on other family history sites, or have more than one account on Ancestry?  Once you have some clues, online obituaries can offer a lot of family information.

Having no tree, or having one side of a tree incomplete, might be a sign that your match is searching for their own biological family – something to bear in mind if you research their tree.

If your Match has a private tree…

Check their Ancestry profile page: 

  • They may have other public trees available (although there is no guarantee that any public trees are different versions of their private tree).

Try an educated guess

  • Look at the shared match group that your match belongs to.
  • You may already have some ideas as to what this group has in common
  • Try searching your match list for surnames/locations that seem significant within the group
  • Even though the tree is private, you may find that it appears in the search results. 


  • The new ThruLines tools may also reveal some hints about connections within private trees.  As with all hints, use this sort of information as a staring point for more research, not as facts.

Remember to add any information you discover about the match to their notes for later reference.

If your Match has an unlinked tree…
  • Use with care! An unlinked tree might be a fantastically accurate, well-researched tree for your match, and they just haven’t linked their DNA to their tree. 
    • or…
  • it could be a tree they created for a friend/neighbour, or might reflect their adoptive family, so could easily lead you down the wrong path. 

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