How to build a Mirror Tree

Mirror Tree Blog Post1

After exploring mirror trees with the main roadblock of my family tree (my foundling grandfather), I now have a better understanding  of what a mirror tree is, and how useful it can be  for revealing ancestors that left incomplete paper trails. Mirror trees offer a method for organizing genetic DNA matches to help those with unknown ancestors (adoptees, orphans and foundlings) identify biological ancestors.

Here are  five steps to create a mirror tree:

Step 1: Take an Ancestry DNA test

Currently a ‘mirror tree’ can only be created in Ancestry, since it is the only genetic DNA company that allows DNA to be linked to family trees.  When you take a DNA test through Ancestry you can connect your DNA to a family tree that you have saved (or can create) on your Ancestry account. Taking this test is easy. You simply spit in a tube, put the tube in an Ancestry provided envelope, and mail it back to Ancestry.  The most difficult part of this test is waiting for the results. It usually takes 6 to 8 weeks for the DNA to be processed, but if a lot of tests are returned at the same time, it could take 6 to 8 weeks before the DNA even makes it to the lab to begin the processing.  Ancestry has great deals around holidays where you can order the test for under $80 with shipping included.

Step 2: Identify close DNA cousins 

Once your DNA results are available, you can view your DNA Matches. These are other people that have taken the DNA test that share DNA with you, and are likely genetic relatives of yours.  Estimates of the relation of these DNA matches to you are categorized either as parent/child, close family, first cousin, second cousin, third cousin, fourth cousin, or distant cousin. To create a mirror tree, you need a DNA match that is a close relative to you (3rd cousin or closer). If you have a 3rd cousin match or closer, continue to step 3. If you only have 4th cousin to distant cousin DNA matches,  you can try to create a mirror tree with a 4th cousin match, but it will be much more work, and less likely lead you to close ancestors. Instead, I recommend that you wait until more people test with DNA and you match a closer cousin.

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

Step 3:  Select the closest DNA cousin with the best family tree

Of your closest DNA cousins, how do you choose which one to create a mirror tree off of? You select the closest cousin that has the most useful and available family tree.

First, you need a close DNA cousin that has a family tree attached to it.

Second, the family tree of the close cousin needs to have enough non-living people listed in it for it to be valuable.  To identify the ones that have attached family trees, look for a green flow-chart (see image below) to the right of the user ID of the cousin.  A number next to the family tree symbol (green flow-chart) will reveals how many people are in their family tree.  The higher the number, the less research you will need to do later on to fill in your mirror tree.  Trees with less then 20 people may or may not be useful.  If the 20 people in the tree are all living (cousins, siblings, children, and parents), then you will not see the names of these individuals or be able to identify their ancestors. If the 20 people listed in the tree are not living, and are the grand parents and great grandparents of the DNA cousin, then you will have enough information to create a valuable mirror tree.

Third, you need to be able to see the people listed in your DNA cousins family tree. When you create a family tree in Ancestry, you have the option to make it ‘private’ or ‘public’.  If it is private, then other Ancestry users can only see the family tree after requesting from you to see it. If it is a public family tree then any Ancestry user can see the tree.  If there is an image of a black lock next to the tree symbol (see image below), then your DNA cousin’s tree is ‘private’, and you will need to contact them to gain access to the tree.  If there is not a lock symbol next to the tree symbol, then DNA match’s tree is ‘public’, and you can view it by clicking the ‘view match’ button.

A DNA cousin with these symbols next to it means that they have their DNA linked to a private (black lock) family tree (green flow-chart) that has 1029 people in it.
A DNA cousin with these symbols next to it means that they have their DNA linked to a private (black lock) family tree (green flow-chart) that has 1032 people in it.

Step 4: Create a family tree that copies the close DNA cousin’s tree

Once you have identified a close DNA cousin that has a family tree linked to their DNA, you can build a mirror tree. A mirror tree is a copy of this cousin’s tree.  From the Ancestry Home page, you can create a tree from the ‘trees’ tab at the top of the page. It is recommended that in settings, you make this tree private.  If you choose not to make this tree private, then please clearly explain in the tree description that it is a mirror tree.  A explanatory name for the tree would be helpful too.  You can name it something like  “Mirror Tree for an Adoptee”.

The ‘home’ person of your mirror tree will be the close cousin DNA match that you chose in step 3. You can then type in their parents, grandparents, aunts/uncles and cousins. How close a DNA match the cousin is, will determine how many generations back to fill in the tree. If possible, fill in the tree with ancestors one generation further back from the generation you would expect to have a shared ancestor with the DNA cousin. For example, if you are estimated to be a first cousin to your DNA match, then you would likely share a grandparent, and should fill in all of your DNA cousins, grandparents AND great grandparents.  If you are a second cousin match, go back another generation and list all of your DNA matches great-great grandparents.

Step 5: Link your DNA in lieu of the DNA cousin in the mirror tree

Now that you have created your mirror tree, you need to link your DNA to the tree. You want to link your DNA to the home person of the mirror tree (your close DNA cousin). To get to your DNA reults , select the ‘DNA’ tab from the top of the Ancestry home page.  Now select the ‘Settings’ button which is located in the top right corner. Half way down the page there is a section titled, ‘Family Tree Linking’. You will want to edit the family tree linked to the test to be the mirror tree you just created.

Congratulations, you have created a mirror tree. Now you just need to wait for Ancestry’s matching algorithms to work their magic.  You should start to see DNA cousin matches who share ancestors to this mirror tree within a week or so. If you do not see any, use your research skills to fill in as many ancestors on your mirror tree as possible.

See my next blog post, I have created a mirror tree, now what? to learn how to use a mirror tree to identify biological ancestors for someone with unknown parentage .

31 thoughts on “How to build a Mirror Tree

  1. Unfortunately not at this time. I hope that we can do that in the future. One way to keep your experimenting quiet is to make the new tree private and give it the same name as your other tree that the DNA is currently connected to. It is sneaky, but no one but you will know what you are exploring.

  2. Hi Meagan, It sounds like your tree is more complete than your DNA match so it would be. better if he made a mirror tree of yours and attached his DNA. This is a tangly web to sort through. I hope it goes well for you!

  3. Oh Ellen, that is a tough spot to be in. Sometimes it helps to have another adoptee ally in your quest, but it is extra challenging when there are multiple adoptees. It is not uncommon though. I have noticed that families with an adoption often have more adoptions. The family patterns through generations is fascinating. You will need to dig deep into the patience chamber and wait for the right matches to come through.

  4. Could you please clarify: Do I need to put the individual whose DNA I’m attaching somewhere within the tree as a floater, or not at all? The ‘Tree Settings’ ask for the home person on the tree (the individual I’m mirroring) BUT also, who YOU are in the tree. Do I put the individual I’m mirroring in both of those?

  5. Can a person connect DNA to two separate trees. I am working on a possible NPE but want to keep it quiet at the moment.

  6. I have a question. I have a possible half-uncle (from my paternal grandfather) match on my DNA (we’re also 4th cousins on my paternal grandmother’s side). His sister (4th cousin but they have different fathers so she’s not also a half-aunt) suggested I make a mirror tree to see if we can get a link to someone in my tree. The issue here is that we don’t know if my grandfather is actually his father and he only has his mother’s side in his tree since he does not know who his father is. Maybe I’m just confused, but should he do a mirror tree for MY tree or should I do one for his? I feel like me doing one for his would not work out correctly. Sorry, we’ve been working on this so long I think we’re all just getting confused!

  7. Hi Amy. Your DNA matches are more determined by the number of cMs and the number of DNA segments you share with other DNA testers than the information in either of your trees. Attaching your DNA to another person will not impact your DNA matches. It will however impact your DNA shared hints. If you have some known family in your tree that you have DNA matches to, and these people are not in the new tree you are going to link to, you will no longer have a shared hint with these matches. That is one of the main reasons I recommend using the Ancestry stars to identify those DNA matches that you already know the relationship to. If you do not have any known biological ancestor, then you do not need to worry about this. Check out my latest blog post on using Ancestry stars if you want more information on that.

  8. I have a question that no one seems to have asked here (or elsewhere on similar blogs); if I switch my DNA results to a new “home person” in the mirror tree, I’m now breaking the link between me (in my own tree) and my results. Won’t this mean that I’ll stop getting matches as new people start testing? Maybe I’m missing something here, but that worries me.

  9. That is great news!! I will have to explore that. I knew you can attach DNA to your family tree, but I did not know that you can create a new tree, and move your DNA to it. Thank you for the suggestion.

  10. You are NOT kidding! Most of the battle is finding a decent match with enough information to work with. And of course, the struggle of no responses. But once in a while we get a break. I hopw you catch yours soon.

  11. Thank you for your compliment! I am happy that you found this blog post helpful. I was inspired to write it, because I struggled to find a clear explanation of how to build a mirror tree when I fist began exploring this concept.

    I noticed that my estimated relationship changed when I moved DNA around a tree. I do not have an answer to why this happens (yet), but am not sure the change means that you are researching the wrong line. I would focus more on the shared DNA matches then the estimated relationships. When you put the DNA back to your cousin’s father, the relationship should return to 2nd or 3rd cousins. The fact that you have 10 DNA matches on the mirror tree, is a great sign that you are on to something. Do not underestimate your intuition. You will need to fllow your insticts and hunches to navigating through a mirror tree.

  12. A first cousin match is a great find! It sounds like you are on the right track to finding your elusive ancestor. Does your cousin’s father have any shared DNA matches since you moved his DNA to the research tree? If so, take note of whom on the tree those matches descend from. It should help you narrow on a family line of the research tree to focus on. Great work!

  13. “To identify the ones that have attached family trees, look for a green flow-chart (see image below) to the right of the user ID of the cousin.”

    I have the flow-chart icon on all my matches, tree or not.

  14. Great article, however I believe your statement “Currently a ‘mirror tree’ can only be created in Ancestry, since it is //the only genetic DNA company that allows DNA to be linked to family trees//.” is incorrect in that FTDNA //does// link their DNA tests to a family tree you can create on their site.

  15. Oh, and let’s not forget that out of hundreds of pages of DNA matches, 95% have no tree associated with them whatsoever. Of the remaining 5%, 50% of those trees will have 3 people. The remaining few dozen trees will be locked. No one will answer your request for access to their tree except for one person, who, answered your request last week after two years, while you were on vacation, and then, coincidentally, just died the day before you read their response- which said, “Sorry, I don’t have any of those names in my tree.”

  16. Your directions for creating a mirror tree are clear and easy to follow, and the first I’ve seen that explained how to make one. Thank you!

    I followed your directions using a possible third cousin’s tree and found each one of our shared matches included the same couple. There were a total of 11 matches – ten 4C and one distant cousin. Then I found a daughter of theirs with the same first name (Delilah, not real common) as my 2nd Great Grandmother, and slid that person in as my 3rd Great Grandmother, attached her to the man I’d already identified as my 3rd Great Grandfather. Dates and locations are keen possibilities but I haven’t begun to research yet.

    Here’s my concern: the possible third cousin I started my mirror tree with matches me at 90 cM/3 segments which could make us third cousins or second cousins twice removed, but we’re showing as 5th cousins once removed when I attach my DNA to myself on this mirror tree. Now I’m totally confused. That must mean that I match this mirrored third cousin in another line, which is disappointing because my brick wall was my 3rd Great Grandmother. Am I approaching this correctly?

  17. We are trying to find the biological parents/family for our grandfather born in 1912 and put up for adoption about 1917. Recently his son (my cousin’s father) had a 1st cousin match on Ancestry and this match is totally separate and not connected to any matches on his mother’s side of the family. We are 99% sure this is on the biological family side. The match had a tree with only 34 people and the only name was the match’s father’s name. I took that name and created a research tree and have built it out on all lines back to the late 1700s in Hanover County, VA. My hopes were to learn how to do the mirror tree as you have written about on your blog. Tonight I connected my cousin’s father’s DNA to the base person on the tree which is the 1st cousin match. The match is 832 centimorgans and 34 segments. I’m hoping I have done this correctly! I have a lot to learn so this isn’t making a lot of sense yet!

  18. In a mirror tree, you do not need to have you in the tree, at least initially. Your DNA is attached to someone else at first. Also the home person does not need to match the person the DNA is attached to. I suggest making the home person, the DNA cousin that you first attach your DNA to.

  19. I don’t understand the way that I can have myself AND the DNA match both as the Home Person on the mirror tree. I have entered the most recent person on the DNA match’s tree as Home Person and built the mirror tree using the DNA match’s data. Then I’ve gone to the Settings on my DNA tree and tried making the link, but it wants to know where I am on the mirror tree…?

  20. Yes, that is exactly what you do. Unfortunately there is not an easier way to copy trees. I suppose you could ask the owner of the tree to download the gedcom for you, then upload it to Ancestry. That would be less work. The most important values to input to the mirror tree are the full name, the birth date and location, and the death date and location. It is not important to add all of the records. I add records if they confirm a relationship that was not in the tree that I copied from. IUsually you will have to check the tree you copied, and add names to it to find your common ancestor.

  21. Perhaps I missed something – once you identify the tree and can access it do you just open it in a different tab/window and then manually create a tree from scratch by entering all of the desired ancestors? How much information do you enter for each person just birth/death dates?

  22. Thanks for this initial article on a subject that needs a lot more development. Looking forward to the next installment !

  23. That is a great question. So far it has been mostly faith combined with a little hope. One of the descendants of whom I suspect is the biological grandfather has recently tested with FamilyTree DNA. We are in the waiting phase of the testing process. If we share DNA equivalent to a first cousin or closer, then I will have validation that mirror tree’s work. If she is not a biological relative, then I will probably write a post about the problems with trusting to find biological relatives.

    Those ‘New Ancestor Discoveries’ are ridiculous (eye roll)! They spark curiosity that always ends in disappointment. Like you said, the 4th cousin of an in law. I will follow your lead and provide honest feedback on how useless that feature is. I do like their new beta feature though, ‘genetic communities’. It matches the paper trail of my known ancestors better than the ethnicity estimates do. I am fairly new to 23andMe, but am liking it so far. It is more easy-to-use then FamilyTree, and I find members are more responsive to inquiries. Being able to see the chromosome comparison of your matches is really cool too.

    You mentioned that you do not know for certain who your biological parents are. Does that mean you have some potential prospects of who they are?

  24. I’ve had the least amount of success with AncestryDNA, by far, 23andMe has been the better website to find what I need. It’s nearly impossible to get more than about ten percent of AncestryDNA matches to upload to GEDmatch for a true comparison.

    Also, my original question is, why do you have faith that you’re getting a true result from using mirror trees? About a year ago, tried something that purported to tell me who my relatives are, and they asked how I liked the feature.

    I blasted it, because it was obviously wrong. While I do not know for certain my biological parents, all matches that I’ve pursued in the last two years have undeniably French-Canadian heritage. Ancestry gave me the names of a couple from early New England that had zero French heritage. Perhaps they were the ancestor of some in-laws of a fourth cousin whose family came to New England from Quebec.

    Add to that the startlingly lame matching algorithms that incorporate insignificant segments in a total, and you may appreciate my lack of trust in DNA companies that presume to tell me who I’m related to.

  25. Agreed that you can not do true triangulation with Ancestry. I also agree that the DNA circles are useless. The shaky green leaves on DNA matches though are wonderful, and can be very helpful. When you make a mirror tree, you will at first just get the cousin that inspired the tree as a shared match. But as you fill in more people on that tree, more of your DNA matches will have those green leafs and share common ancestors to that tree. This is what is useful, since you can start to see which branch of the original cousins tree you descend from. It is a lot of work though! Triangulation is likely a more efficient way. To me, triangulation is advanced genetic genealogy, and a mirror tree is intermediate. Ancestry may be more fluffy than the other DNA companies, but the number of DNA testers far outrank the other genealogy DNA companies, and that alone makes them a valuable DNA genealogy source. Thank you for your comments and the follow. :)

  26. Aren’t you just going to end up with relatives of the person who is the match? Ancestry doesn’t give us a chromosome browser to do real triangulation, they prefer to use gimmicks, like ancestor circles, shaky leaf hints, and that kind of Magic-8-Ball type of hocus-pocus to tell us about our heritage.

    Without knowing exactly how the mechanisms behind these things work, how can we have any assurance that we are getting a valid result? I’m a computer hardware guy, but even I know what the programmers all say, “Garbage in, garbage out.”

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