The 23andMe family tree feature was introduced in 2019, and is very different from a traditional genealogy tree.
What is a 23andMe Family Tree?
A 23andMe family tree is a graphical representation of the potential relationships between you and your DNA relatives. If you opt in, 23andMe calculates your genetic tree.
If Ancestry’s tree software is known for the green leaf icon, then 23andMe may become known for their wavy lines.
Here’s an excerpt of a tree which has been edited by the DNA tester:
The thick golden lines represent direct pedigree relationships: parents, grandparents, and so forth.
The thinner lines represent collateral lines within your tree: the descendants of your great-aunts, for example.
Unlike traditional family tree software, the entire representation is displayed on a single page. You will likely need to zoom in and out to work with particular areas.
How Does the 23andMe Family Tree Work?
The 23andMe tree is created by an algorithm that analyses how much DNA is shared between you and a set of your DNA relatives. 23andMe has not divulged much technical detail, but I will infer some broader aspects of the process.
This is my take on a high-level breakdown of how your family tree is generated…
The algorithm chooses one or more of your DNA matches to work with. How does it choose which ones? I’ll address that in a later section.
For now, we’ll work through an example with Mary, Bob, and Joe.
Let’s say that you share 20% of DNA with Mary, a DNA relative that you haven’t figured out yet. That’s just shy of 1500 centimorgans. Yes, this is a lot of DNA, but it’s easier to work this through with a more obvious relationship.
When you look at Mary’s list of Relatives in Common, you see Bob at the top of the list. Bob shares 9% of DNA with you, and 49% with Mary.
Joe shares 23% of DNA with you but is not on the Relatives in Common lists of Mary or Bob.
Step 1: Cluster the chosen DNA relatives
I assume that the 23andMe algorithm arranges the chosen DNA relatives into groups of overlapping shared DNA.
Here is a crude cluster diagram of Mary, Bob, and Joe:
Step 2: Predict the Possible Genetic Relationships
The next step is to draw up a list of the possible genetic relationships between your and the three DNA relatives, and then between themselves.
23andMe gives us the percentage of shared DNA, so we can also do this ourselves.
If you share 20% of DNA with Mary, then these are the more likely relationships: grandmother, aunt, half-sister, niece, or granddaughter. There are also some other relationships that are less statistically possible.
Similarly, Joe is likely to be your grandfather, uncle, nephew, half-brother, or grandson.
Bob is more challenging. There are thirteen relationships of similar likelihood – including those head-scratchers like half first cousin and half great-uncle.
Let’s lay it all out like below. The reason for the alignment will become clear.
Now let’s consider the possible relationships between them.
23andMe knows that Bob shares 49% of DNA with Mary. So, Bob is either Mary’s father or her son.
Joe has no matches with either Mary or Bob, so we can safely say that he does not share a grandparent with either of them.
But we couldn’t say, for example, that this is a paternal/maternal divide for you. Joe could share great-great grandparents with Mary, and still not have inherited any shared segments of DNA.
Step 3: Filter the possible relationships based on other factors
Which is it, Bob? Are you Mary’s father or her son?
We can’t tell based on the genetic data, but 23andMe has access to more information. For example, 23andMe knows its customers’ dates of birth.
Let’s say you are 50 years of age, Bob is 25, and Mary is 48. Oh, and Joe is the most senior at 72.
Wherever 23andMe slots Mary into your genetic tree, Bob will be placed beneath her as her son.
You and Mary are of similar age, so they can strike a line through grandmother.
Theoretically, they can’t rule out the 72-year-old Joe as your nephew – but it would be a highly unusual age-gap.
We’re now into genealogical statistics. The table above is aligned horizontally with the more likely groupings of age. Each possibility can be allocated a score based on age-range.
Are there factors other than age?
The documentation mentions the pattern of shared DNA segments, and of relatives in common. It would be interesting to know the weighting assigned to these factors, but that’s not publicly available.
Step 4: Generate a single tree that represents the most likely possibilities
Crunch the numbers, tot up the possibility scores, pick a winner…and boom!
There is your single 23andMe family tree with one or more of your DNA relatives slotted into their theoretical places.
It’s an impressive fusion of genetics, statistics, and visualization.
If you’re an old-hand at investigating your genetic relationships, you may be thinking – but this is what I do with tools like the Shared CM Project at the DNA Painter website.
Well, exactly. The underlying techniques are not new.
But I bet you don’t choose to do this blindly, with no reference to your known family relationships.
Unless you are in a position of unknown parentage, you will add factors to your investigation such as ancestral surnames and place names.
23andMe does not incorporate traditional family trees that customers may have linked in their profiles. I don’t think they make use of the list of ancestral surnames that so few of my DNA relatives fill out.
This family tree is based entirely on DNA and statistics. Which is impressive. But is it useful?
Working on Your 23andMe Family Tree
23andMe emphasizes that they aim to give you a head start when building your family tree. So, they slot in one ore more of your genetic relatives – along with a whole lot of placeholders that you need to fill in yourself.
Here’s a pic of my genetic tree, untouched by (my) human hands:
You don’t need to squint. I’ll tell you that they slotted in ONE of my DNA relatives. Just the one.
This is where the marketing message doesn’t quite fit reality, at least for me. This is the sales pitch:
“Building a family tree from scratch can be time-consuming and overwhelming. 23andMe makes it easier by automatically generating a family tree for you.”
They have, in fact, generated a load of placeholders. With an estimated third cousin, I must fill in at least seven of the placeholders to establish the relationship.
To be fair, this 3rd cousin is my highest DNA relative on 23andMe. I know that many customers will have plenty of relatives within the range of 2nd cousin on the website. I assume that their starting trees are a bit less sparse at the lowest level.
Regardless, there are placeholders that won’t fill in themselves! So, let’s get to it.
Adding Family Members to Your 23andMe Family Tree
The first thing to do is to add a parent. I know my single DNA relative is on my maternal side, due to an ethnic comparison – but I don’t know anything else! So, I started by adding my mother.
In traditional genealogy trees, the paternal side is visually on the left. 23andMe says pshaw to your traditions – might be left, might not be. The reason is that they are not deducing whether your matches or maternal or paternal unless you’ve tested either parent.
I think its chance that my match is to the right of the screen, but that’s okay with me.
The first time you enter a relative, you are required to read a short privacy statement.
Information you enter about living relatives will be visible only to you. Any information you enter about deceased relatives will be displayed to your DNA relatives and connections.
I’ve bolded the second sentence. It has considerable consequences, which I’ll address in the section on Privacy. It also isn’t true at the time of writing in 2020 – I can’t see the trees of my DNA relatives. I assume this is “coming soon”.
I’m not sure if the next question would appear if I had tested a parent: is this paternal or maternal?
Dod you notice how there is a uniform color scheme across both sides of my initial tree? At this point, 23andMe will start differentiating areas of the tree by color.
Entering Names, Dates, and Gender in a 23andMe Tree
23andMe looks for limited information about each person. For example, there is only input for birth and death dates and locations.
I respect the attempt at gender-inclusivity, but I think the designers have made a bit of a hash of it.
They only provide two choices (male or female), with the info pop-up telling us that picking either is optional. But if you pick female and want to revert to an undefined status…you can’t.
I think you have to delete the entire entry and start again.
Current Tree Limits
At the time of writing in late 2020, there are some limits of entry into the family tree.
I’ve seen mention of a limit of 250 people in forums, but I haven’t tested this (with manual entry? No, thanks!)
But I did test the number of generations you could go back. The beta version may have had a limit, but I found that 23andMe currently doesn’t stop you from adding circles above circles.
However, it stops naming the generations after “5th-great-grandfather”. Prior generations are named “Distant Ancestor”.
23andMe’s lack of interest in generations before 5th great-great is understandable. At that point, you are inheriting less than 1% of the ancestor’s DNA. Therefore, the information is not useful for the genetic tree.
Endogamy (cousin marriages) is not recognized
You cannot add a relationship between individuals across paternal and maternal branches. As 23andMe puts it in their FAQ: your dad’s parents were second cousins? Computer says no! (I’m paraphrasing a little).
They’re going to have to address this because low levels of endogamy are common. The documentation says it’s not “currently” possible, so I imagine it’s on the roadmap.
Can You Import a Family Tree?
No, you can’t import or bulk upload details to your family tree.
What’s that? You’ve got a family tree elsewhere? Doesn’t matter. You have to type it in again.
23andMe does not offer the ability to import a GEDCOM file, for example. Or transfer information from the trees you link to in your profile. Or do anything with those ancestral surnames you listed in your account profile.
As I was entering my grandmother’s place of birth, I was asking myself: haven’t I given them this already? Why, yes. Yes, I had. Your 23andMe enhanced profile looks for your grandparents’ birth locations:
So, my typing up my family tree was accompanied by some grinding of teeth.
Can You Export or Share your 23andMe Family Tree?
Ancestry and MyHeritage are two DNA testing companies that allow you to maintain your family trees online.
Both offer the facility to download your trees to a standard format, known as a GEDCOM file. They also let you grant permission to other people to view your online family tree (without a paid subscription).
In contrast, 23andMe does not offer the ability to export or download your family tree. Nor can you share your tree with others.
The only work-around I can find is to take a screen-capture of your zoomed-out tree. The problem is that names and other text are very tiny when you’re capturing a full tree.
Which DNA Relatives Are Automatically Added to Your Tree?
You can’t choose which of your DNA relatives are automatically added to your 23andMe family tree. These are chosen for you by the algorithm. But which matches are chosen? And what criteria is used to pick some and not others?
I’m just asking for a friend…
Nah, I’m selfishly asking for myself. With one solitary DNA relative in my tree, I took a long look at the documentation to see if I could somehow trigger another arrival. This is all I got:
To kick-start your tree, 23andMe looks at your closest 20 DNA relatives and predicts their relationships to each other. After this initial tree prediction, new  2nd cousins and closer will show up in your unplaced relatives list.
Well, I can tell you that the above statement in the FAQ is not strictly true.
My single added relative is my highest shared match and is estimated as a 3rd cousin. There is one additional DNA relative in my “unplaced relatives” list. This second lady shares even less DNA with me and is estimated as 4th cousin.
I’m wondering if this is the marketing department twisting the arms of the engineers. It reminds me of 23andMe’s big rival, Ancestry, rolling out a major new feature – to be greeted by disappointment from those who didn’t reap any benefit. (I’m thinking of the now-defunct DNA circles. I never got a single one).
Am I getting a few breadcrumbs, so I don’t feel left out? More importantly…is there a way to trigger some new DNA additions?
How Do You Get DNA Relatives Calculated Into Your Tree?
There are two obvious answers here.
The first is to have patience and wait for newer closer relatives to turn up on 23andMe.
The second is to arrange for closer relatives to test with 23andMe.
Another source of hope is that the algorithm improves in its interpretation of the genetic data to hand. Regarding the paternal vs maternal divide, perhaps the 23andMe algorithm can bring the X chromosome into play.
Maybe some tweaks are still to come.
Privacy and the 23andMe Family Tree
And this is in line with other major online family tree services. Ancestry and MyHeritage have similar policies for the default privacy options of their hosted trees.
However, both these rivals to 23andMe give customers the option to make their trees fully private. It’s not clear whether 23andMe will provide this option.
I want to help and collaborate with my DNA relatives, so I maintain a public tree online on both Ancestry and MyHeritage.
However, I don’t want to lead people astray when I’m chasing speculative leads and experimenting with potential relationships with my genetic matches.
My approach, which I learned from other hobbyists, is to put my speculation into private research trees. When I’ve gathered enough genealogical evidence to support the tree entries and relationships, I add them to my public tree.
My concern with my 23andMe family tree is that my actions in filling in the placeholders will be conducted in public view of my DNA relatives.
How Do You Recalculate Your 23andMe Family Tree?
This article required a bit of experimenting with my tree. For example, I entered eight fake generations on an unknown line to see how far back it would go.
So, I wanted to revert to factory settings, so to speak.
I’d seen mention of triggering a recalculation of the tree – but when I went looking for a big red reset button…I couldn’t find it. Resorting to Google took me to the FAQ page, which had me completely confused. Until I realized that the recalculate feature is hidden within the FAQ section!
Expand the dropdown at the end of the section…
And you get to see a big red reset button:
You’re welcome! Clicking the button gives you an informational message to wait for 10-15 minutes for the tree to be recalculated.
When I refreshed my tree after 10 minutes, I was excited to see the display below. Where before I’d had one unplaced relative, I now had fifteen.
Did I now have fourteen more DNA relatives added to the lowest level of the tree? No. These were fourteen entries that I had added when playing with the tree. 23andMe saves them here, if I need to put them back into the placeholders.
23andMe isn’t the only DNA site that automates the generation of sections of your family tree based on proprietary algorithms.
Ancestry has ThruLines, and MyHeritage has Theories of Family Relativity. Both these offerings use the family trees hosted on their sites to construct hypothetical lines.
The major difference to 23andMe is that the latter doesn’t use existing family tree information at all. It’s purely based on DNA and genetic possibilities.
The Historic Dance Partners of 23andMe
The corporate origins of 23andMe were not in genealogy and family history.
23andMe was founded in 2006 to provide consumer genetic testing with a focus on health. So, its family tree offerings have long seemed like a bit of an afterthought.
Over half of respondents to a survey by the company in 2020 said that they were interested in their family trees.
So, what do companies do when customers want a feature outside their wheelhouse? Sometimes they gobble up another company that already does that one thing better. And sometimes they collaborate.
23andMe has twice chosen to collaborate. They started with MyHeritage.
23andMe and MyHeritage
23andMe had a rudimentary tree editor before 2015. But then it partnered with MyHeritage, who are leading providers of online family tree services.
23andMe customers used to be able to create a fairly small tree with access to MyHeritage record archives. In fact, 23andMe turned off its own tree editor. New testers had to use MyHeritage to create their trees.
There was a lot of noise about software and platform integration, and then the whole partnership was discontinued.
The Wild Years of Many Dance Partners
When I tested with 23andMe in 2017, the in-house genealogy offering was two-fold. These options are still available, by the way:
- Enter a list of ancestral surnames in your account profile
- Take a whirl with one of many approved family tree “partners”
The first option is kinda lame, but better than nothing.
The second option involves providing a web link to your family tree hosted elsewhere. This may not be a comprehensive list, but these are some of the possible websites that 23andMe would accept:
Some customers were irritated that they could only choose one of the many sites where they kept their family trees. They had the bright idea of setting up a blog page with as many links as they wanted. But when they tried to point their 23andMe accounts at the customized web pages, they realized there was an approved list. Foiled!
My web link points at my Ancestry family tree. But it’s a pain in the neck for my 23andMe DNA matches who don’t also have an account with Ancestry.
They have to register for a (free) Ancestry account to view my tree. This was never an ideal implementation.
23andMe and FamilySearch
FamilySearch is a massive genealogical organization, operated by the LDS Church. 23andMe started a partnership with them in 2019.
Customers were invited to “enhance your 23andMe profile with FamilySearch.”
This involved either associating your existing tree on FamilySearch with your 23andMe account or creating a new attached tree on the external site.
This collaboration was nixed less than a year later.
At this point you gotta wonder – is it the partners of 23andMe who are at fault in these brief relationships? Or is 23andMe’s track record not looking so great?
But by this time, that choice between build versus buy had been reversed. 23andMe had built the beta version of its own family tree offering.
What About GrandTree?
The GrandTree feature has nothing to do with the automated family tree service. But for completeness, I’ll touch upon it here.
This seems to be a little-mentioned tool tucked away in the recesses of 23andMe.
If your grandparents have tested with 23andMe, this tool shows you how much DNA you get from them. I can’t give a personal account on this one, as I do not have a tested grandparent.
Having read some other accounts, I see that 23andMe correlates the DNA inheritance with their health and traits reports.
This aspect of 23andMe isn’t a draw for me, but here is the link for you to investigate.
Adoptees, Unknown Parentage, and the Genetic Tree
I’ve seen mention in forums that this feature could be useful for people with unknown parentage. As 23andMe says, it provides a head start.
Let’s go back to my example of Mary, Bob, and Joe.
If the tester were lucky enough to see these closer matches turn up in their family tree, it could be helpful to get a visualization of Mary and Bob’s relationship being mother and son.
Sure, an experienced researcher could work this out using various tools. But 23andMe is putting the results of these complex tools into the hands of a wider audience. That’s a real benefit!
Still, the usefulness will depend on who has tested amongst the customer’s genetic relatives.
My unknown third cousin dropped into my tree is not helpful. Now, if that person had an available family tree going back to her 2nd great grandparents, then that would be golden.
There isn’t any sign that 23andMe is moving towards incorporating genealogical trees on their platform, which is a pity.
I recommend that people seeking to resolve unknown parentage should choose the Ancestry DNA kit – if they can only affort to purchase one test.
But both kits, and other DNA sites, can be part of an overall strategy for researching genetic relatives. Check out our review of best DNA tests for adopted adults to unlock family heritage.
My Verdict – A Work in Progress
I took a wander around the social media forums to see if there was a general verdict as to the usefulness of this genetic tree.
When 23andMe introduced the software in beta, there were a lot of teething problems with crazy results. By and large, the major issues seem to have been ironed out.
Some customers are very happy with the feature. This blog commenter gives a good summation of how it helps:
“The tree helps me understand cousin relationships and what it means in cM when someone is on one branch vs another or under different grandparents. Since I just can’t remember all this, the tree helps me visualize these concepts.”
At the other end of the spectrum, some people are irritated that 23andMe has moved even further away from genealogical research through traditional family trees.
Then there’s the middle ground that’s pretty much: okay, it’s cool, but what do we do with it?
One Redditor commented that he had put some effort into building out his tree by adding family members with names, dates, and locations. And he said:
“But after I finished, I was left with asking myself what was the point of spending an hour entering data?”
I’m not sure that 23andMe has clearly demonstrated the benefits to its customers.
Having said that, the company has put a considerable amount of development effort into this feature. Introduced in late 2019, it seems that 2020 was about eliminating the glitches and refining the process.
Personally, I’m very interested to see the future progress for the feature. And I’ve got my fingers crossed that a few more DNA relatives drop into my family tree.