No, it’s not a game show or a board game – it’s a fantastic tool in the hands of serious genetic genealogy researchers! What are the Odds? (WATO) is a tool developed by Leah Larkin, and Jonny Perl at DNAPainter.com. You can use this tool to further your research in cases where you don’t know how a person fits into a family tree, such as in adoption or unknown parentage research cases. It can also be used as a sanity check when building a family tree to help you see if you have placed a DNA match into the correct location in a family tree.
A WATO pedigree chart starts with an ancestor, and then you add descendants in each generation down to the DNA matches in a tester’s DNA match list. You can add a hypothesis about where the DNA tester fits into the WATO tree, or you can ask the program to generate hypotheses for you.
Scores are given to hypotheses according to the probability that a specific location in the family tree is the correct one for the DNA tester or “Target.” You can use the scores to help you figure out if you have chosen the most likely relationship that the Target shares with the people in the family tree.
WATO is a tool to use after you have done some initial research and have discovered the following:
- A research objective
- The amount of DNA that a DNA tester shares with their DNA matches – use the shared cM amount from any DNA testing company.
- How the DNA matches are related – this requires looking at the DNA matches and the family trees attached to their DNA profiles at the DNA testing companies. Identifying the MRCA may also involve building a family tree for a DNA match to connect them with the ancestors at the top of the descendancy tree.
To find the most recent common ancestor (MRCA) of your DNA matches – use the shared matches feature at a DNA company and look at the family trees of the DNA matches. Do you see some of the same ancestors in multiple DNA matches’ family trees? To do this, use the following features at the DNA companies:
- 23andMe “Relatives in Common”
- AncestryDNA “Shared matches”
- Family Tree DNA “In Common With” (ICW)
- MyHeritage “Shared DNA Matches”
You can also group shared matches using the DNAGedcom Client and Collins-Leeds method or Genetic Affairs AutoClusters for Family Tree DNA and 23andMe. Order a MyHeritage AutoCluster report, use GEDmatch.com Tier 1 tool, “Clusters With AutoTree, Closest to Single Kit Version,” and eliminate clusters that you know are related to an ancestor on the opposite parent’s side. Focus on a group or cluster of DNA matches that have the MRCA that is most plausible.
- See if you can find that ancestor on the FamilySearch Family tree, choose the descendancy view to identify children, grandchildren, etc., of the MRCA. This can help you find descendants that may link a stubby tree from a DNA match to more generations.
The WATO tool does not work if there is endogamy in the family line – because you are related to each of the people in more than one way. It also doesn’t work when there is a double cousin or ¾ sibling relationship.
What Are The Odds? (WATO) Beta v2 is the latest version of the tools, and it has the following additional features:
- Import a GEDCOM file in this version – a previously created family tree converted to a Genealogy Data Communication file. You can make this text file with your personal genealogy software from the program that stores your family history research.
- It uses the latest relationship probabilities from AncestryDNA.
- You can use DNA matches that share less than 40 cM with the tester. The probabilities based on smaller amounts of DNA are available
The estimated relationships may be a generation closer in the v2 beta calculations than in version 1. Some relationships that were not considered possible in the first version of WATO are slightly likely to be possible now.
I recommend using WATO BETA V2.
Get Started with v2
Go to DNAPainter.com and click on “Visit WATO” inside the rectangle entitled “Use matches to identify an unknown ancestor.” The next screen will be the What Are The Odds? version 1 page.
Alternatively, you can click on “Tools” in the top navy blue bar to go to this page, where you can choose a tool. Choose “What Are The Odds? BETA V2.”
If you are logged in to DNA Painter, you’ll see this page with a list of the available DNA analysis tools. Choose WATO BETA V2
This page will open; it is a blank canvas where you can build your chart.
To learn more:
- Click on Help to find more instructions and answers to common questions
- The Help section can be accessed from the home page or from within the WATO tool.
- Specific information about WATO can be found by clicking on the “Show Tips” and
Read about v2″ hyperlinks.
- Learn more at https://dnapainter.com/help/wato-faq
Use these steps to build the chart:
- Enter the Target name – this is the DNA tester – either yourself or someone who has given you access to their DNA match list. The target is the person you are trying to fit into a family tree. Next, add the year the target was born, then the question you are hoping to answer.
- Start building the tree. Hover over the “Most recent common ancestor or couple” box, and add the name. [The names in this example are fictitious.]
- Next, hover over the box with the ancestor’s name, and click “Add child.” Next, hover over the child box to see the dropdown menu, click on “Edit Name,” and type the child’s name in the box.
4. To add more information, hover over the box again, choose “Enter Match cM” and enter the amount of DNA in cM that the tester shares with DNA matches. You can add additional information such as birth and death years, gender, and spouses.
5. Add half-relationships if they exist.
6. Add your own hypotheses in the dropdown box, or
7. Click on Suggest Hypotheses
Hypotheses are possible places where the tested person target could fit in the tree –WATO can help you figure out which one is the likely place
I’ve been working on an unknown parentage case and built a large Lucidchart with many DNA matches that have relatively short family trees. It has been challenging to connect the family trees to shared common ancestors in Ireland and England. I tried WATO to see what information I could learn.
First, I decided to look at a family whose members share the most DNA with the Target. I have puzzled over the amount of shared DNA in this family. The family members are established in known relationships. However, it is odd to me that first cousins and a pair of siblings share vastly different amounts of DNA with the DNA tester.
When I clicked on the “Suggest Hypotheses” box, WATO suggested five hypotheses, each with a score of one.
Green boxes have probability scores –which indicates how likely a specific hypothesis is. Red boxes indicate that the proposed relationship is not statistically possible.
Here are the hypotheses for a family in another genetic network in the unknown parentage case. The names are fictitious in this example, too. There is much more difference in the probability scores in this WATO chart.
The hypotheses give me ideas about where to focus my research on specific family lines by seeking records to build the family tree. I’ll work to fill in the people in the highest probability places in the chart.
In her 2020 Rootstech presentation, Leah Larkin said,
“The scores are all relative to each other; the absolute score is not important. If there is a difference between two hypotheses, that is:
1-3 fold – it is barely worth a mention
3-20 fold is positive support for the hypothesis
20-150-fold is strong support for the hypothesis
Over 150-fold is very strong support for the hypothesis.
The best-case scenario is a score of 1 which means that all other hypotheses are ruled out.”
The most likely hypotheses are at the top of the list, which is found by scrolling down the page. The top score is 775, and the other scores are 361, 188, 115, and 3. The largest difference is between the score of 3 and 155, and the report states that 115 is about 38 times more likely than 3. This falls into the category of “strong support” for the hypothesis.
As you scroll down the page farther, you’ll find the Score calculation, which lists the DNA match names, the amount of shared DNA, and a number of relationships with a probability that the amount of shared DNA corresponds with the various relationships.
With the probabilities generated by the “What Are The Odds?” tool, I have more ideas about which family lines I should focus on as the research continues. As I identify more ancestors and descendants through documentary genealogical research, I’ll be able to rule out hypotheses and discover the most likely biological father candidates. To definitively determine the biological father, the closest living relatives need to be found. If they are willing to take a DNA test, the birth father can be confirmed or refuted.
After creating a WATO tree, you can save it and send a link to a relative or a client to see your research.
Try using the What Are The Odds? tool in your DNA and family history research!
Find additional information and guidance in these tutorials:
Introduction to What Are the Odds? (WATO) by Leah Larkin, Rootstech 2020
‘What are the Odds?’ An online tool that can help solve DNA puzzles, 3 June 2020, by Jonny Perl
Working with WATO: Centimorgan Adjustments by Leah Larkin
-  “Introduction to What Are the Odds? (WATO)” by Leah Larkin, Rootstech 2020 (https://www.rootstech.org/video/introduction-to-what-are-the-odds?lang=eng : accessed 29 October 2021).
Very clear instructions to use WATO..I have a case to use it with next week!
I’m glad this post is helpful. WATO is an amazing tool!!
I found your inclusion of Leah Larkin’s discussion on WATO odds ratios to be very helpful. You put things into perspective for me. I have just starting to use WATO. My test case was to place an unknown match from 23&Me into my family tree.. As I was adding cM for common matches, I realized my match was probably in a poorly covered section of my tree. In the course of filling cousins into the blanks, I came across the unknown match’s surname. I worked down a generation and found the correct given name for my previously unplaced match. I returned to my WATO hypotheses to see what odds it had given my documented match. It wasn’t the strongest hypothesis, so I compared the odds ratio for my second tier of possibilities (with the same score as each other). Dividing the 2nd by the 1st showed that the second tier of hypotheses was 60% as likely as the strongest. It seemed those were still pretty likely scenarios for placement. However my target match was actually in the group of equally likely hypotheses. These were 25% as likely as the strongest hypothesis. These seemed “long shots” to me, but a hypothesis with 1 out of 4 odds was 100% true. I wondered if my instincts were “off”. By Leah’s approach, dividing the higher odds ratio by the lower gave me about a 2-fold advantage over the 2nd tier. Continuing, the strongest odds ratio had a 4-fold advantage over the 3rd tier. By Leah’s reckoning my correct hypothesis had positive support. This helped me “calibrate” my intuition about the odds ratios and gain a useful perspective. Thank you for bringing this valuable lesson to us.