23andMe is adding a much-needed tree tool for genetic genealogists to help DNA matches learn how they may be related. Here’s what it looks like and how to get access.
This post was updated on 10 March 2020.
23andMe is perhaps best known globally for the Health part of its popular Health + Ancestry test. But given its enormous pool of more than 10 million testers—second only to Ancestry’s at 15 million—a lot of genealogy connections happen on 23andMe, too. However, one drawback for those looking for family connections on 23andMe has been the lack of ability to share and compare family trees with your DNA matches to figure out how you’re related.
Well, that’s changing! The site is beta-testing a new Family Tree reconstruction tool that uses your shared DNA to visually reassemble a genetic family tree with your DNA matches on it.
23andMe Family Tree – Beta
23andMe is beta-testing a new Family Tree builder that works based only on your genetics, with no input from your genealogy. This is especially great news for those who don’t know their family trees or haven’t entered the information into a tree file yet.
“Your genetic family tree [on 23andMe] is built automatically by an algorithm that predicts relationships based the DNA shared between you and your DNA Relatives,” explains a recent company statement. “The size of your family tree depends on how many connections and DNA Relatives you have close relationships with in the 23andMe database. Participating in 23andMe’s DNA Relatives tool helps improve the experience. As the 23andMe database grows, customers may see their trees expand.
Update in March 2020 from 23andMe:
“As of February 2020, 23andMe customers are now able to edit and add relationships to their Family Tree for richer storytelling and accuracy. Family Tree builders are now able to move individuals and groups of relatives elsewhere, and add relatives, even if they haven’t participated in 23andMe’s services. Customers can also add personal notes to the tree including ancestor names, important dates, and photos, and send messages to relatives who may offer more information and fill in further gaps on their Family Tree.”
Here’s what a portion of my reconstructed 23andMe family tree looks like (with names/faces of my DNA matches removed for privacy):
This is my kind of chart. Simple and beautiful, but also instructive. This is just the kind of thinking and mapping process we have to use to visualize our connections to DNA matches based on our total shared centimorgans, but 23andme is trying to do it for you.
In the image above, you can clearly see the two branches of my tree in different colors, blue for dad and pink for mom. While it takes a few minutes (ok, maybe longer than that) of studying to figure out exactly what the picture is portraying, relying on your knowledge of how families are organized can help. For example, everyone has two parents and four grandparents (two couples). You can see my parents, JH and CH. Then above my dad you see two medium dots – his parents. You can only see one of my mom’s pink, medium dots in this image (you can’t see the other one, it is off the page, that side of her family is HUGE). But if we march back in my tree, we should encounter my four great grandparent couples. And we do! The tool has identified both couples on my dad’s side, and both for my mom (which, again you can’t see).
Take just a minute to realize how absolutely amazing this is!
Even though there aren’t any names, you can clearly see which relatives of yours, and of your matches should be connecting you. All you have to do now, is DO GENEALOGY!
Opt In to 23andMe Beta Testing
To access the new 23andMe Family Tree, current customers have to opt in to Beta testing. (Beta testing just means they’re still tweaking it, so it may not be perfect yet and you understand that.) It’s easy to join Beta. Click on your username, then click Settings. Scroll down to turn on Beta participation.
Once you’ve joined Beta, you’ll be able to select the Family Tree option from the Family and Friends dropdown menu, as shown here.
23andMe’s new genetic Family Tree (beta) is included in the brand-new edition of my unique quick reference guide to using 23andMe. This inexpensive must-have guide helps you understand and navigate all the great tools and information that come with your 23andMe test.
I would NOT recommend that people opt in to the beta Family Tree just yet, at least not while it isn’t even following its own rules.
What those "rules" seem to be — according to 23andMe — are that the tree will take into consideration: (1) the amount of DNA shared between you and a match; (2) the ages of you and the match; and (3) the relationship of your relatives to each other, not just to you.
Well, included among the profiles in my account are a half brother-half sister pair. Their sharing is 12.9%, which fits "half sibling" perfectly. Of course, based on shared DNA alone, it could also represent a grandparent-grandchild relationship, as well as uncle-niece or aunt-nephew.
But 23andMe says that in addition to the amount of sharing, the tree considers ages. The half siblings were born in consecutive years. This, one would think, would be enough to push the tree into considering the half sibling relationship over uncle-niece or aunt-nephew.
Despite that, the half brother’s tree originally showed his half sister as his niece; and the half sister’s tree showed her half brother as her uncle. While that can be justified on the basis of DNA alone, the ages don’t really support this choice.
And what about the relationship of other relatives to each other? Well, in the "uncle’s" tree there was a relative who shared 705 cM with him. There is a very high probability that this person is either his 1st cousin or his 1st cousin once removed, yet the tree listed her as a 2nd cousin — a virtual impossibility with this much sharing.
Why? I’m not sure, but I suspect the tree is programmed to recognize that a 1st cousin to a full uncle would have to be 1st cousin once removed to his niece; and a 1st cousin once removed to the uncle would have to be a 2nd cousin to the niece. Yet this person shared absolutely NO DNA with the niece. Therefore, this person must be more distant from the niece than "2nd cousin".
The reality is, it’s extremely unlikely that someone who shares 705 cM with you would share 0 cM with your full niece or nephew. It’s so unlikely that it should have made the tree algorithm "rethink" whether it was correct to estimate these profiles as uncle and niece instead of as the half siblings they actually are.
Well, after a few messages back and forth between me and 23andMe’s help desk, the relationship has been changed in the half brother’s tree. His half sister is no longer shown as his niece, but as his half sister. Hooray!
Only, not so fast. The half sister’s tree was also changed. Her half brother is no longer shown as her uncle. No. Now he’s her NEPHEW. She was born the year after he was, but she’s his aunt. I’ll admit that’s possible, but it isn’t typical — and it certainly isn’t anything that would favor this prediction on the part of the tree.
And what about the relationships of relatives to each other? Well, the half sister has someone who is shown as her 1st cousin who shares 12.8% with her. But how much does this relative share with the "aunt’s" full nephew, who should be a 1st cousin once removed? Nothing at all.
In this case, the sharing was so high that even the Family Tree didn’t dare to predict them as "2nd" cousins just to avoid the illogic of someone not sharing any DNA with a 1st cousin once removed. Yet in spite of that, the tree could not figure out that this person must not be related to the "nephew" at all — and therefore, (full) aunt-nephew would essentially be ruled out.
Clearly, the tree has difficulty with the concept that the most recent common ancestor of two people need not be part of a couple. Yes, this is recognized in the half brother’s tree — but I suspect that required some "help" from the ancestry team. Help that, unfortunately, they failed to provide in the half sister’s tree.
Surely it’s possible to write an algorithm that will, for any set of matching individuals, check both to ensure that their relationship with each other was at least consistent. This was true for the first effort, even though it was wrong. If the half brother’s tree shows his half sister as his niece, then the half sister’s tree should show her half brother as her uncle.
Likewise, if the half sister is shown as as "half sister" in her brother’s tree, then logically the half brother should be shown as "half brother" in his sister’s tree — not as her nephew!
To me, this sort of error should have been worked out even before the algorithm was released to beta. This, in my opinion, is an alpha-level error that should have been found and corrected during in-house testing.
Gary, thank you so much for this in depth study of how this feature is working within some of the known relationships you have access to. Very helpful to see where the holes are in the system. I am sure many will appreciate your comments.
How is it that my mother isn’t added to my tree but my father is? She shows as my mother in the dna relatives section but not on the beta tree. I am not understanding the algorithm they are using. The tree is showing relatives on my mothers fathers side as being on her mothers side they are mingled in several places. If there were a way I could correct their link to me it would be a better program.
Cheryl, As today’s update to this post shows, you can now edit your tree on 23andMe. Wishing you the best!
What happened to all of the data that I manually input into this program. Gone! All that hard work. I am so upset that my family information has disappeared.
John, I hear you. Unfortunately you are not the first person to experience this. I wish I had more answers. I wish I could get your data back. I don’t know if it works better now that it is not in "Beta," but I don’t think it really has the ability to retain the information if it is always updating.
My brother recently joined. He is listed in my DNA relative list but doesn’t show up on Family Tree even after ‘refresh’. Why? Also he has spent a lot of time updating our Family Tree. How can I see what he has done? We will have the same Family Tree.
Make sure your brother has given permission for others to see him as a DNA match. He can adjust that in his settings. But even then, this tree feature we talk about here is not shared between people, but only viewable by each individual through their account. So unfortunately your brother’s hard work won’t help you.