What Are the Odds? Read the FAQ New interface! switch to beta probabilities
WATO lets you use the amounts of DNA you share with multiple matches to help figure out where you might fit into their tree
Before you start you'll need:
- A research question (e.g. 'Who was my father?')
- Shared cM amounts for a group of matches from your match list
- Knowledge of how these matches are related to each other
How to use:
- Enter your target name and year of birth. This is either you or the name or another person who you're trying to fit into the tree using their matches.
- Build a simple tree by hovering on a node and clicking add child, or alternatively import a GEDCOM
- Enter the amounts of DNA the target shares with people in the tree by hovering over each match and clicking Enter match cM
- To find out whether a position in the tree is feasible based on the amounts of shared DNA, hover over any node and click Add hypothesis. Or click Suggest Hypotheses to have WATO do this for you.
- The site will generate an odds ratio for each hypothesis. If the odds are above zero, the hypothesis is possible, and the higher a score is, the more likely it is. This does not mean a score has to be high in order for a hypothesis to be correct.
While the scores cannot give you a definitive answer, they can guide you in the right direction.
Upload a GEDCOM (family tree) file here. Please note: this will *replace* anything you may have already entered for this WATO tree.
Loading GEDCOM data. If you have a large file, this may take a little while
If you have any issues importing your family tree, I would be very grateful if you could email a copy to email@example.com for testing. Many thanks!
Sorry - there was a problem with your file. Either it wasn't a file the site can read, or there weren't any people in it.
Your file should be a GEDCOM file with the file extension '.ged' or '.gedcom'. Please check the file and try again, or if you think your file is fine, please feel free to email it to firstname.lastname@example.org
Each match now shows its relationship with Hypothesis and the calculated probability of that relationship based on the number of cMs of DNA shared
Target name: Target Birth year: YYYY
My research question is: Enter the question you are trying to answer here
The file you loaded was imported successfullyX
This is an example tree. Create a new tree by clicking here
You are viewing this tree in read-only mode. If you would like to make edits, please click Save and make a copy in your DNA Painter account first.
You are currently in read only mode. If you make edits to this tree, they will not be saved. If you'd like to save it to your DNA Painter account, please sign in or register (free). You'll then see the option to save a copy of this tree.
Experimental: you can save an image of this tree. The results may vary according to your browser. For the best results, try to maximize the size of the window before clicking this button. This feature works best in the Chrome, Firefox and Safari browsers.
You can also download the data for this tree locally and load it back into the tool later (or send it to someone else so they can load it in).
To do this, click the button below.
- Move nodes by dragging them to different positions in the tree.
- Uncheck the box to turn this off and re-enable editing.
- Download or duplicate via the 'Save' menu first if you need a backup.
Hover over a person for options. Scroll to the right to see children.
Ranking of Hypotheses
After you've added matches and hypotheses to a tree, hypotheses will appear here.
This table shows the following for each match:
- Amount of shared DNA in cMs
- The genealogical relationship with each hypothesis based on its position in the tree (for example 3rd cousin)
- The probability that the amount of cM shared corresponds to this relationship
These individual probabilities are then used to calculate the combined odds ratio used for the score
If a probability appears in red as '0.00%', this means this relationship is not statistically possible given the shared cM amount you've entered.The odds ratios are made by comparing all hypotheses that are considered possible and then determining the relative likelhood of each. For more information please see the FAQ.
View ranking of hypotheses Back to top
About this tool
This tool has been built to help solve DNA puzzles (including unknown parentage cases) by undertaking the calculations described by Leah Larkin in her series Science the heck out of your DNA...
© DNA Painter 2018-2022
Due to the lack of statistical data available, this tool has limited applications to the following scenarios:
- Double-cousin relationships
- 3/4 sibling relationships
- Matches with endogamous ancestry
WATO uses probabilities simulated by AncestryDNA and originally described in their White Paper.
The underlying calculations that convert the compounded probabilities into the odds ratio used for the score were developed by Dr. Andrew Millard.
Valuable advice on the user interface and functionality was provided by Mike Mulligan. Many thanks also to the early beta testers from the GG&T group on Facebook.
The static tree layout was adapted from an example by Peiwen Lu.