I Have Created a Mirror Tree, Now What?

MirrorTree Part 2

The real work with mirror trees is not in creating them, but what you do with them once they are created. If you have created a mirror tree, and do not know how to use it to discover those hard-to-find family members, then you are at the right blog.

Here are 5 steps to use a mirror tree to find ancestors for those with unknown parentage:

Step 1. Create a mirror tree

Follow the 5 Steps to create a mirror tree from the last blog post.

Step 2. Explore shared ancestor hints 

Once your mirror tree has ancestors back several generations you should start to see shared ancestor hints from your AncestryDNA home page.  These hints highlight the people that share DNA with you that also have ancestor(s) in their tree that matches those in your mirror tree.  These shared ancestor hints will help you to identify which ancestor you and your DNA cousin share.

To see if you have any shared ancestor hints, look at the ‘DNA Matches’ section of your AncestryDNA home page (see image below). This section offers three summary statistics which count how many Shared Ancestor Hints, Starred matches, and 4th cousins or closer  are associated with your DNA.

An example of shared matched ancestors on a modified mirror tree. The green leafs show common ancestors between the mirror tree and the linked DNA. There are 10.
An example of DNA Matches from the AncestryDNA home page. In this example there are 11 shared ancestor hints.

If the DNA cousin you linked your DNA to has their DNA linked to a family tree, then you should at least see one shared ancestor hint on your AncestryDNA home page.  If you gathered the ancestors for your mirror tree from a source other than a linked tree of your DNA cousin, then you may initially see a ‘0’ next to these hints. Sometimes it takes time for Ancestry’s algorithm to identify these matches, but I found that they usually show up within 24 hours  from when a new ancestor is added to the mirror tree.

To explore the shared matches, click on the ‘View All DNA Matches’ button under the DNA match summary statistics. This will bring you to a list of the people that Ancestry thinks are genetically related to you (see image below). By default these are sorted from closest relatives to most distant relatives.  There are filter options near the top of this page that allows you to only show the DNA cousins that either have shared ancestor hints, are new, or are starred.

An example of DNA matches sorted by relationships.
An example of DNA matches sorted by relationships.

Select the ‘hints’ filter tab  to see which of these cousins have direct ancestors in their tree that match those of your mirror tree. To see the common ancestor a matched cousin has with your mirror tree,  click on the ‘View Match’ button.  The common ancestor will be revealed as well as a side-by side comparison of how your mirror-tree cousin and the matched DNA cousin relate to  this common ancestor (see image below).

An example of the shared ancestor hint from a DNA match .
An example of the shared ancestor hint from a DNA match .

If there are identical surnames in the DNA cousin’s tree to your mirror tree, they will be listed below the shared ancestor description.  Clicking on these surnames will give you a side-by-side comparison of the ancestors with the surname in the two trees. Look carefully at these ancestors, because sometimes they are the same and show other common ancestors.

An example of a summary of shared surnames.
An example of a summary of shared surnames.
An example of ancestors that share surnames between two trees of DNA cousins with shared matches. In this case, the two trees have the same ancestor, Mary Hardin Perkins.
An example of ancestors that share surnames between two trees of DNA cousins with shared matches. In this case, the two trees have the same ancestor, Mary Hardin Perkins.

Possible reasons your mirror tree may not have any shared DNA matches (or only the one from the DNA cousin the tree was derived from) is because:

  • The mirror tree is not filled out completely
  • The mirror tree is filled out incorrectly (identified wrong ancestors)
  • You do not have a lot of DNA Cousins to work with.
  • The mirror tree does not have enough generations of ancestors

If you find yourself in this situation, it could be a very frustrating, but I encourage you to keep trying.

To get more productivity from these more frustrating mirror trees try to:

  • review all of the people in your tree to identify and correct any errors
  • take the ancestors back another generation
  • wait for more people to DNA test with Ancestry.

If these actions do not get you more shared ancestor hints, then you may want to take a break from this mirror tree, and try to start a new one from a different close DNA cousin cousin.

Step 3. Identify the ancestor you share with the mirror tree cousin. 

Now that you have some shared match hints, and have identified potential common ancestors, you want to identify which ancestor you and the DNA cousin from the mirror tree have in common. If it is clear from your work in step 2 who this common ancestor is, then you can skip this step. Otherwise, it helps to create a visual aid of the shared ancestor hints that I call a Shared Ancestor Map.

To create this map, print or take a screen capture of your mirror tree, and mark all of the ancestors on the tree that are also listed in the trees of your DNA shared matches from step 2.  This will allow you to see a pattern of lineage. Usually it will be linear, and point you towards an ancestor that you most likely descend from.

Below is an image of an example of a shared ancestor map I created for a mirror tree based off of a 4th cousin DNA match to my mother.  This mirror tree had three shared DNA matches. One of the matches was the 4th DNA cousin that was used to create the mirror tree. The other two matches were estimated as 5th-8th DNA cousins and had two different ancestors in common with the mirror tree. I shaded these common ancestors on the mirror tree (see below), and was happy to see that they formed a line.

Example of a Shared Ancestor Map from 2 shared ancestry hints of a mirror tree.
Example of a Shared Ancestor Map from 2 shared ancestry hints of a mirror tree.

Since the mirror tree in the example above is derived from a 4th cousin match, I expect the common ancestor between the 4th cousin and my mother to be a 3rd great grandparent. This shared match map suggests that this common ancestor is a parent of Martha Elizabeth Holt. Through research, I was able to identify these parents whom both or one, my Mom likely descends from.

Step 4: Build the mirror tree from the identified common ancestor 

Now that an ancestor has been identified that both you and your mirror cousin descend from, you can use this ancestor as a new reference point for your mirror tree.  You are likely a descendant of one of the children of the ancestor identified in step 3, but may descend from one of their siblings.  First, build the mirror tree up by adding the parents and grandparents of the new reference ancestor. Then build the mirror tree down by adding all of the children of the common ancestor.  Make sure to add the spouses of these children to the mirror tree as well as the spouse’s parents and grandparents.

Choose one of the children that is not the child already identified as an ancestor of your mirror cousin, and link your DNA to that child.  Wait 24 hours or so and check your shared ancestor hints. They should differ from the hints you had before when your DNA was linked to the cousin you built the tree from. Create a new shared DNA map with these hints and see if any patterns lead to further clues to your direct parentage.

If you find matches on the spouses’ ancestors, then this child and spouse are your direct ancestors (grandparents).  If not, try linking your DNA to another child, and see if there are additional shared ancestor hints and if you match their spouses’ ancestors .  If you do not match any of the children’s spouses, then the child that gives you the most DNA hints when your DNA is linked to them, is most likely the one that you descend from.

Below is an example of a shared ancestor map for a child of the common ancestor that was identified from my 4th cousin mirror tree in the example from step 3. When I linked my Mom’s DNA to the child, Mary Madeline Holt, I received 7 shared DNA matches that allowed me to shade in almost all of the ancestors on the newly created shared ancestor map.  This confirmed to me that I was on the right trail, and my mother was very likely a descendant of William Holt and Martha Ridley.  Some of the shared matches listed Mary Holt as the common ancestor, which led me to believe that she was likely my Mom’s 2nd Great Grandmother.

An example of using shared ancestor map from Mary M Holt for a 4th cousin created mirror tree.
An example of using shared ancestor map from Mary M Holt for a 4th cousin created mirror tree. There were 7 shared ancestor hints for this tree.

Step 5. Repeat steps 3 and 4

Once you identify which child of the original identified common ancestor you descend from, you want to make them your new reference point in the mirror tree.  Their parents, grandparents, and possibly great grandparents are already in your mirror tree  so there is no need to build the tree up from this new reference point.  But you will need to build their tree down another generation by finding and adding their children, children’s spouses, and the spouses parents to the mirror tree.  Then link your DNA to one of these newly added children, check for new shared ancestor hints, create a shared ancestor map, and see which hints guide you to your next likely grandparent.

This process should be repeated until you get to the generation of the parent you are hoping to identify with the mirror tree. If you know the date and location of where your ancestor with unknown parentage was born, then use this information to guide you to whom to link your DNA to.

Continuing with the 4th cousin mirror tree example from above, I repeated steps 3 and 4 two times until I found the potential father (William Norsworthy Gordon) of my ancestor with unknown parentage (my maternal grandfather).  The real clues for this example is when I received shared match hints for the ancestors of the spouses of the reference ancestor (who the DNA was linked to). This was very helpful since these ancestors that the DNA was linked to had multiple spouses.

Congratulations, you now can use a mirror tree to help you identify potential biological ancestors for someone with unknown parentage. This is a complicated process that makes most sense when you apply it to your own genetic research.  The more mirror trees you create and are successful with, the easier and simpler the process becomes.

Once you have identified potential parents of an elusive ancestor, you can try to contact living descendants to see if they are willing to take a DNA test to confirm the genetic relationship.  I am currently waiting on DNA results of a direct descendant of William Norsworthy Gordon to see if he is indeed my great grandfather.

If you or anyone you know have questions about creating or analyzing mirror trees please leave a question or comment below, and I will help as much as I can.

23 thoughts on “I Have Created a Mirror Tree, Now What?

  1. Hi Bonnie,

    I have noticed this too, and think that Ancestry is slow at times to reveal the SAHs. I also noticed that if the names are not spelled correctly or if one is using capital letters vs small letters in a name that it will not show up. This is frustrating! I think it is a problem on Ancestry’s end though and not yours.

  2. Hi Linda,
    Yes, you can do this, and I recommend it. Since you are not positive on his biological father, you may want to try two mirror trees. One with the man you think is the father, and one blank. If you have DNA matches to his mother’s side, then you may actually be a half-sibling through his mother. You can at least rule this out and have confirmation that you and this sibling share a father and not a mother. That is too bad that he is not open to further exploration. That could change with time, but may not. By making a mirror tree with his name and your DNA, any matches you get to that tree will be a relative of your hared parent. That information alone will be helpful! Good luck and keep me posted.

  3. Hi Dannie,

    I wish I had advice for you, but this is the toughest to solve. I have several Mirror Trees similar to this that I am stuck on. It sounds like Endogamy. I have been hoping to reveal a way to sort these confusing trees, but have not figured it out yet. I think you just have to wait and hope that a closer cousin match shows up soon. I will let you know if I find any solutions to this problem.

  4. Linda, 29 is a good number. Do you think there is endogamy in your tree? Do you have a lot of French Canadian or Jewish ancestors by any chance? Endogomus families add a whole new level of hardness with mirror trees.

  5. Hi Beirne, Hmm, There may be endogamy at play. I would first try the paternal grandmother side since there are more matches there. If you are not getting anywhere there then switch over to the mother’s side.

  6. While awaiting your answer about the half brother mirror tree, I went ahead with a close 3rd cousin match, copied her tree, linked my DNA to her, waited a good week, ended up 29 direct ancestor surname matches, now I’m confused and not sure where to start now.


  7. I found out through ancestry DNA that I have a probable half brother, he doesn’t have a tree, nor does he want to be involved in finding out that his father may not be his bio father. I on the other hand I have been searching for my bio father for a long time, I was wondering if, since he does not have a tree, can I build a tree, using his name and my DNA? I’ve already done some research and know names of his mother and our possible bio fathers (There are 2 possibilities), their parents etc. Would that work like a mirror tree?


  8. Is it possible that Ancestry might use an out of date tree when calculating SAHs? If I build out the mirror tree and then link the DNA, Ancestry seems to not recognize the added branches sometimes. I build all my mirror trees for my target individual in a single tree rather than separate mirror trees …could that be an issue too?

  9. My mothers grandfather is a mystery to us. My mother has a 3-4th cousin who has the same 3rd great grandfather 4 times in her paternal line. I believe he is the one we are matching. Will his being repeated so many times confuse a mirror tree? We are DNA matching over 100 people with this particular person in the trees. Only one of our cousins, with this person in their tree is a 3-4th cousin (the one I mentioned above), all the rest are 4-5 and 5-8 cousins. Thanks for any help.

  10. I just did my first mirror tree and was pleased to find 3 matches with trees. From the same person, though, one match is through the mother and the others split from the paternal grandmother. How do I best proceed with three different branches?

  11. i just created a mirror tree and am waiting on the results. Your explanation really makes sense to me. Thank you so much for taking the time to share this.

  12. Hi Dennis. No, the starred matches and the 4th cousin or closer numbers should not change. Since your shared ancestors did change, you do not need to wait the 24 hours. The changes in the shared matches should provide you some clues to which line you share a common ancestor with this cousin. I recommend keeping an open mind when using mirror trees for this purpose. I usually have preconceived ideas of how a cousin is related due to surname recognition. More often than not, my preconceived ideas of the connection are wrong.

  13. After reading your post yesterday, I created a mirror tree to see if it would help discover the elusive link between a cousin and me. The shared ancestors hints changed, but the starred matches and the 4th cousins or closer have not. I realize it’s been less than 24 hours. Will the latter two change as well?

  14. Hi Judy, I recommend waiting a day to see if there are any changes. Sometimes a half of a day is all that is needed for the change to kick in. Waiting for the results is the hardest part for me when I move DNA around.

  15. I’m finding your 2 posts on building and using mirror trees really helpful. I’ve identified 2 lines using the hints although 2 brothers marry 2 sisters so there are a few grandchildren to try. Can I ask – when I link my Ancestry dna to one of the grandchildren (having added their ancestry) and get the same 5 hints that I’ve had before nearly straight away, should I wait for another couple of days to see if more hints appear?
    Or is that it and I can move straight on to another child?

  16. Hi Celia, Great work on your tree! You are at the most difficult stage of the mirror tree. Getting a lot of shared hints is the kind of problem that you want in a mirror tree, but as you get closer to the biological ancestor it gets more difficult to sort through the matches and identify differences between the children. And YES this is much more trying when their are a lot of children, and the process requires a ton of patience! As you get closer to your biological ancestor, the rule that “those with the most hints are likely your person” may not always apply, and you will need to resort to traditional investigation techniques. If you know the birth year (or better month and year) and/or birth location you need to focus on those who share this information or those who could possibly have children that do. Send me a Facebook message or email so we can talk about your tree in more detail. I need to know more information to help you, and will have a lot of questions to ask. treeeeeeena@hotmail.com or https://www.facebook.com/treena.hartley

  17. Thank you very much for sharing this information. I have built a mirror tree and I am moving my DNA around by linking it with the children (and spouses) of who I have determined to be the common ancestor couple. If I receive shared ancestor hints on both the child and spouse, I move down a generation to their children (and spouses), link my DNA once again to the children and spouses, and keep going in this manner. The problem is that I’m receiving so many shared ancestor hints that I feel I am doing something wrong and it has become a massive undertaking since each ancestor seems to have a ton of children to move my DNA to. Would you be willing to take a quick look at my tree to see if I am doing it correctly? In advance, thank you!

  18. I know that “getting closer” feeling. It is what drives us to keep searching. It sounds like you are on the right track. I will look at your mirror tree, and get back to you soon.

  19. I only have the information I have on his parents are what my great grandfather put on his marriage record. But at this point I think he made it up. There is only one person that could possibly take a Y-DNA test but so far he has refused to do so. But I keep trying. I have written about Willie Beaton but that was more about my researching his adopted family and the area and people where he lived to see if I could garner clues about who is biological family could be. So now I’m trying the DNA route and a mirror tree. I truly feel I’m getting closer.

  20. Your welcome! I hope this helps you with your adopted ancestor. Do you have any information on your great grandfather’s biological parents? For me, a Y-DNA test that a direct male descendant took was extremely helpful! I am curious of your mirror tree progress and research so far on your great-grandfather. Have you written about him in your blog? If so, can you share the link(s) with me?

  21. Thank you so much for your article. I have been using a mirror tree to breakdown the brickwall of my great grandfather who was adopted. I’ve stumbled along and have used much of the process you spell out here already. But I didn’t know the direction I should take now. Your suggestions may be just what I’m missing.

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