Quick Tip: Shared Matches at AncestryDNA

When I get a new mystery DNA match—unknown connection, possibly no tree at all—the first thing I check is how much DNA they share with me in centimorgans, the unit we use to measure autosomal DNA.  I can then plug that number into the Shared cM Project Tool to get a sense of which relationships are possible and, more importantly, which are most likely.

Next, I want to know which of my other DNA relatives the mystery person matches.  All of the main testing companies provide this information, variously called “Shared Matches” (AncestryDNA), “Relatives in Common” (23andMe), “Shared DNA Matches” (MyHeritage), or “In Common With” (Family Tree DNA).

Ideally, I want to know not just that my mystery person shares DNA with, say, Cousin Bryan but also how much DNA they share with Cousin Bryan.  Conveniently, both 23andMe and MyHeritage include that information in their tools; AncestryDNA and Family Tree DNA do not, for privacy reasons.

What’s a girl to do if she really wants that information from an AncestryDNA match?  Ask them!

AncestryDNA recently started including the amount of DNA (centimorgans and number of segments) on the main match page.  I initially reach out to my mystery matches with some possible surnames and to ask if they’re willing to collaborate to find the connection.  If they reply, I ask them to click on Shared Matches with me, copy the entire page, and paste it into a message back to me.  (Pasting might not work on a tablet device, but it should work on a computer.)

It’s easy for them, and it lets me see our shared matches from their perspective.  I can then provide them with some quick feedback on the possible connection.

I recently used this trick with an adoptee who matched a client of mine.  I’d already built a descendant tree of about 20 matches for the client, so when the adoptee sent me the shared match list, I knew exactly where she fit in.  In fact, I identified her birth father within 5 minutes—my new record!

15 thoughts on “Quick Tip: Shared Matches at AncestryDNA”

  1. Would this essentially create some level of triangulation within Ancestry by doing the copy/paste, rather than having them upload theirs results to another site that does the triangulation for you, like Rootsfinder has, or is it more like clustering like the Leeds Method or Genetic Affairs with their auto clustering tool? Or is there much difference? I’m still learning all of this stuff, but it is very fascinating and I have hopes that one day, I’ll see some success too.

    1. This will not do segment triangulation, but it gives a bit more information than the visual clustering methods do, because it tells you how much DNA they share with the other matches. In the adoptee example, I knew the adoptee was descended from my client’s great grandfather, but I couldn’t tell which of his grandfather’s 7 siblings was her ancestor until I saw how much DNA she shared with other people in the family group.

  2. The best thing for people to do would be to add their matches as viewers to their DNA. This makes Ancestry 10 times more useful because it lets you see view the other persons matches, how many cM’s they share with those matches and any notes, even if those matches aren’t shared. This is handy because Ancestry doesn’t show any shared matches that share less than 20cM *with you*, so you might find someone with a great tree and you’re also matched with their second cousin but they don’t show up as shared matches and if they do there’s no indication that they’re closely related.

    This is something MyHeritage does by default (although you can’t see non-matches), and GEDmatch does, but it’s UI isn’t exactly a joy to work with. I’d love Ancestry to make this the default but if you’re reading this consider asking your matches to add you as a viewer and doing so if someone asks for you to add them as a viewer.

    To do so is fairly easy, just go to setting (via the DNA homepage) and it’s the last box

    1. Inviting someone to see your DNA results is an option, but some users are hesitant to do that for privacy reasons. It’s also not as easy as a quick cut-and-paste. When I’m actively helping someone, I ask to be added as a collaborator, but when they’re just a match to the person of interest, I’ve started using this copy-paste approach. It’s great to have options!

      1. Yes, unfortunately some people don’t want to add you as a viewer. I had one person who was very reluctant despite having uploaded their DNA to GEDmatch.

        I think it’s always worth asking, they can only say no but I imagine most people aren’t even aware of the option and how useful it can be. I think it’s preferable to uploading to GEDmatch

    1. I need to write a post about that! Quickly (on a computer): In your Ancestry account, click “DNA” in the black top bar, select “Your DNA Results Summary”. Click the Settings button at top right. On the next page, scroll down to “DNA Ethnicity and Matches Access” and click the blue link to Add a person. You can enter their email address or user name (case sensitive), then set their role as appropriate. A “viewer” can only see the results. A “collaborator” can add notes and change how the DNA is linked to a tree. A “manager” can do all of the above plus download the raw data.

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