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!

25 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.

  3. Thank you for posting. That looks like it could be a very helpful technique! And may be the way forward on the question below….

    Speaking of Shared Matches, I was wondering about how much can be gleaned from Shared Matches that have a common ancestor. I have used the color codes in ancestry.com to “silo” shared matches. As there are 24 colors it works out perfectly to assign a color code to each of the 1G and 2G grandparents (8 + 16). This allows me to plunk a DNA match in the correct silo. Building on this, I put any Shared Match with an identified common ancestor in the closest 2G ancestor’s silo so that I will have the 3G, 4G, 5G matches along that line, in a rough sort of an escalating order, somewhat controlled by the distance of the match (not perfect I think due to the vagaries of DNA getting passed along and also to half-siblings). My question is this: If I have a Shared match with someone who has an identified 5G common ancestor….and a second person also has that person as a shared match, does it mean that the second person also shares that 5G specific ancestor (that being the common ancestor)…or does it mean that the common ancestor could be anywhere down that line? I think it may be the latter, but thought I would check with someone more knowledgeable. Just trying to get the most out of the Shared Match information.

    Thank you, Jeff

    1. The common ancestor could be anywhere on that line. And if your ancestors came from the same small communities a few hundred years ago (which many of our ancestors did), the connection could be on a different line, or there could even be more than one connection.

  4. I was looking at shared matches of shared matches, and keep drilling down until I find a common ancestor. Can I gleam anything from that?

    1. Shared matches of shared matches should for a cluster of people who are related to you on one branch of your tree (barring endogamy). In fact, that’s the the basis of clustering algorithms like at GeneticAffairs.com. Ideally, they can lead you to a set of common ancestors.

  5. I have 350 ancestry dna matches on my “4th cousins or closer” list. All of the matches I have been able to identify are on my fathers side. At the top of my list is a 1st cousin that I know well.
    When I do a shared matches list with my cousin, shouldn’t I get a selection of matches from my fathers side only (maternal matches should not be included)? What I get is that almost all of MY shared matches are on my list of shared matches with my cousin (19 of the top 21). I have no matches that I can connect definitively to my mothers side. Does this make any sense??? There are no cultural issues involve – all of my ancestors are English except for an Irish GGgrandmother.

  6. All four grandparents immigrated 1907 – 1915 from three different parts of England (Kent, Durham, Leeds).

    Re: Could your parents be related?
    Only under the “anything’s possible” theory. I knew all 4 grandparents and all my uncles and aunts and there are NO hidden connections or deep mysteries.

  7. I may have resolved this. If I look at the next 2 screenloads down, 14 out of 24 are NOT
    connected to my cousin. So I think its just a statistical artifact created because no one on my mothers side above 60cm has submitted their DNA to ancestry. My fathers side are obviously more curious 🙂

    Thanks for the help.

  8. i use all 24 groups available in ancestry. with different family names and different cousin

    i have also now mapped as many dna matches in my tree as possible. i use STARRED matches as those that are in my tree so not to use one of my other groups . then i try to map all those into my tree from DNA.

    i also send messages to as many as possible and while looking at shared matches add groups to all in the match that i know are true … so these matches also share that ancestry…

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