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Make Sense of Your DNA Matches Using Statistics Without Exploding Your Brain…Now Even Easier With WATO2!

make sense DNA brain explode
(Image by Klaus Hausmann from Pixabay)

There are multiple tools available these days to help turn your ever-growing list of DNA matches into a wealth of useful genealogical information (and meet new cousins!). Each of the testing companies has its own suite of tools on their site. There are increasing numbers of excellent third-party tools also available to analyse your information using different and more specialised approaches. One of my favourites for the past year or two has been WATO (‘What Are The Odds?’).

What-oh is WATO?

WATO was the brainchild of Leah LaPerle Larkin, aka The DNA Geek. Andrew Millard turned it into an odds calculator, then Jonny Perl transformed it into a user-friendly form. It is now freely available at DNA Painter. WATO uses statistics to help you decide who belongs to who in your DNA zoo, and make sense of your DNA matches.

For anyone whose brain saw the word ‘statistics’ and began to prepare to explode, it’s not like that. You have a few shared matches, and you’ve been able to work out how they are connected to one another. You can now use WATO to work out how your DNA tester fits into their tree. Really really useful for cases of unknown parentage, and for any group of mysterious matches that make no sense on paper.

To make sense of your DNA matches you need to be clear on what you want to know about the DNA subject whose kit you are analysing. For example, “who is her father?”. With WATO v1 you also need to have matches of over 40cM in size. And you need your matches to have common ancestors to one another that you can find or build a tree for.

Previous limitations of WATO

I’ve had great success with this tool but there have been limitations.

  • Being of British birth, my match list of closer relatives is smaller than average. 40cM is not a match size often enough seen in my lists to have used WATO as much as I would have liked.
  • The original WATO is purely about the statistical odds. Hypotheses that are mathematically highly possible may be impossible in real life. The father is not going to be someone who was 3 years old at the time. So red herrings are possible.
  • The statistics are calculated for hypotheses that you as the user put forward. If there’s an angle you don’t think of, the odds won’t be calculated. This is especially important when you consider how many half-relationships are possible in any tree, and the likely source of the answer to your research question.

Introducing…..drumroll……The New and Improved WATO2!

make sense of dna matches WATO2

This month WATO2 was released and the limitations listed above have been addressed. There have also been with some other improvements that have turned it from a great tool into a brilliant one which I’ll be able to use far more frequently!

Firstly, there is a reduced match size requirement. The information used to initially calculate probabilities has grown over time. It is now way more accurate for more distant relationships. Therefore the restriction to matches sharing over 40cM is gone.

Secondly, WATO2 is based on more than just the statistics. It has been ‘humanised’ for increased accuracy. You can add birth and death dates to the people in your tree and WATO2 will take them into consideration when calculating the odds.

Thirdly, you no longer have to think of all the possible places in a tree your DNA target could go. WATO2 will generate all the hypotheses with the click of a single button. I actually squealed when I found out about that! Then you can just weed out and delete any that are calculated to have zero probability, or that you know cannot work (because, for example, that person emigrated).

All my problems were solved! But wait, there was more…

Instead of having to build the tree manually at the DNA Painter site, there is now the option to import a GEDCOM to make the whole thing quicker and easier.

And the other super cool feature for those who have already been using the original WATO … you can easily switch between existing analyses to WATO2 (and back) to compare or update. So you don’t need to start again in order to make sense of your DNA matches!

What has WATO2 done for me?

make sense of dna matches WATO2

I have already managed to identify an unknown father of one of my testers very quickly. He had only half a dozen shared matches. Only three of these could be used in the original WATO due to their small size. The probabilities were much more clearly contrasted in WATO2 as a result of this and the consideration of birth and death dates. Then, by looking at electoral rolls and other records I could eliminate several of the hypotheses. I am at the point where I am very comfortable that his father is identified. If I wasn’t, I could consider target testing to prove it.

How will I be using WATO2 next?

make sense of dna matches WATO2

My next task is to unravel a large Irish family branch originating from Tralee in Kerry. There are multiple shared DNA matches on this line. I have a tree that links most of them. The other interesting aspect is that they all also link to another surname which is not so far present in the tree of my target, other than amongst baptismal sponsors.

Traditional research has not yet managed to unpick these large families with repeated forenames. I was unable to use the original WATO to help with this as we’re looking at the first half of the 19th century, the matches are much smaller than 40cM. Also, the tree is big and my time is scarce!

The plan now is to import the Gedcom, add the match sizes, hit the generate hypothesis button and see what happens. It will feel like a miracle if after all this time, it gets sorted out in an hour!

My Hearty Recommendation

If you are a WATO fan already, no doubt you’re already all over WATO2. If you’ve previously tried it but not had large or plentiful enough matches to answer your questions, now is the time to revisit it and regenerate your WATO hypotheses on WATO2. You can make sense of your DNA matches so much more easily than before. If you’re new to WATO, or even to DNA analysis, head over to DNA Painter and give it a go. It’s free, it’s not a huge time investment for the amount of information generated, and that time is saved multiple times over by narrowing down possibilities to investigate. Go knock down a few DNA brick walls!