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Are you using the What Are The Odds tool on DNA Painter?

What are The Odds Screen Shot

One of the best, if not the best tool, for analyzing DNA is called the What Are The Odds tool on DNA Painter, Affectionately known as the WATO tool, you can analyze an unknown person compared to known DNA matches to make new discoveries.

The Origin of DNA Painter’s What Are The Odds Tool

The WATO Tool was developed by Leah Larkin and it is on Johnny Perl’s website -- This tool is free to use, but sign up for an account on so you can save some of that information.

If you want to learn more about the development of the WATO tool, then go on over to Leah Larkin’s blog and in her series “Science the Heck Out of Your DNA.” She explains all of the statistics behind what the WATO tool is.

But for people who aren’t interested in knowing about the statistics, you can use the What are the Odds tool on DNA painter without the deep dive into math.

VIDEO: What Are The Odds the Best genetic genealogy Tool Ever!

Watch this video on YouTube.

Points to Know Before Using the WATO Tool

There are a few limitations of the What are the Odds tool on DNA Painter.

  1. It is not designed for double relationships. If you have double cousins in some way, then the WATO tool is not necessarily going to give you the results that you want. They may be inaccurate.

  2. The WATO tool produces inaccurate results with 3/4 relationships. For instance, if you have a mother who had two children from different fathers, but those fathers were brothers, then you have 3/4 siblings.

  3. WATO does not handle endogamy well. The reason is that endogamy increases the overall DNA. In other words, even though a relationship may be far distant, you share more DNA similar to a closer relationship.

Create a Known Pedigree Chart with the What Are The Odds on DNA Painter

With these caveats out of the way, it’s time to set up your first WATO tool. Andy explains how in the step-by-step instructions in this video.

Begin by building a pedigree chart of known relationships on your What Are the Odds? workspace on DNA Painter. The basic steps involve:

  1. Add a matches’ name to the canvas.

  2. Start adding parents on the pedigree chart from your match to your common ancestor or ancestral couple.

  3. From the common ancestor, add children until you reach the next match.

  4. There are potentials for half-relationships on your tree.

  5. You would add a child to a parent.

  6. Then use the drop-down menu on WATO to create a half-relationship.

  7. You can add half-relationship possibilities throughout your tree as needed.

Once you have your known family tree built, you can begin testing hypotheses.

Screen capture of the "What are the odds" tool from DNA painter

“What are the Odds?” tool shows the likelihood of your DNA relationships.

Begin Using the WATO Tool to Analyze DNA From Matches

With your known pedigree chart built, you will now use the WATO Tool to compare your DNA matches (with unknown relationship paths to you or your matches) with you and the people on your tree.

Choose one of your DNA matches with whom you do not know the path of the relationship. Let’s call her Elizabeth for this example.

Look at how much DNA Elizabeth shares with the people on your “What are the Odds?” tree. You can take these shared centimorgans (cM) numbers from Ancestry DNA and GEDmatch. If you have shared match percentages, for instance from 23andMe or from MyHeritage, you can also enter the percentage in the WATO tool.

Elizabeth is not on this pedigree chart, or analysis map yet. You will now add possible locations of relationships. If you need help thinking of possibilities, enter the value of the highest cMs Elizabeth shares with anyone on the WATO tree into the Shared cM Project tool.

With the list of possible relationships from this tool, add paths on the workspace to create locations where Elizabeth could potentially appear. You don’t need to know the names of the person through which Elizabeth relates at this time. Just add a path.

At the end of the path, place a spot for where Elizabeth may appear and use the dropdown menu on the WATO tool to signify that this spot is a hypothesis. Add multiple hypotheses to the tree because you want to fully compare the theories to find the most likely path of relationship.

As you add places of a possible relationship to the WATO tool, you’ll begin to see the hypothesis values change.

In Andy’s example, one hypothesis had a score of 68,570 while another had a hypothesis of 1.

Screen capture of the analysis of DNA hypothesis

The “What are the Odds” tool helps you evaluate the likelihood of hypothesis being your relationship paths, but be careful. There’s still more work to do.

What do the What Are The Odd DNA Painter hypothesis values mean?

The differing values on the WATO help you analyze the DNA matches for which you do not know a relationship path to determine the likely ways each person relates. This will help you determine where to focus your research for missing relatives, unknown parents, and more.

If you have a hypothesis with a score of zero, then that path is not possible. You can eliminate the theory connection points from your WATO tool. Focus on the remaining paths.

At the bottom of the workspace, you’ll see a chart of your hypotheses and see just how much more likely one potential relationship path (hypothesis) is compared to another. You may discover that of your five hypotheses, #5 is the most likely. In fact, #5 is twice as #3 but #3 is twice as likely as #4.

Before you cry “Eureka!” You’ll then want to evaluate whether a path is likely.

Rule Out Unlikely Hypothesis Despite What are the Odds Scores

Despite the scores shown on the WATO tool, you need to apply a little logic to your research. Check to see if a hypothesis location is possible.

Perhaps you have a hypothesis with a score of 20,000, which has a high probability for that relationship path to be accurate.

However, if you know that a relative, let’s call him Jack, died a few years ago at the age of 95, some relationship paths are probably not going to work (such as a 25-year-old niece).

Use all the clues you can to narrow down the possible paths of relationships such as birth dates and places of Elizabeth’s parents. Despite the high hypotheses score, you can eliminate unlikely paths based on the genealogical facts of the individuals on the tree.

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Identify Where You Should Look to Connect to Your Unknown DNA matches

When you have filtered out the least likely paths based on biology and the hypothesis score, you can then focus your research to find identify the relatives to which you related to Elizabeth.

You still have more research to do, but using the What are the Odds tool on DNA Painter to analyze your DNA matches can help speed up your discovery process. Try out this free DNA resource and see if you don’t begin to think it’s one of the best tools around.

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