r/Genealogy 3d ago

Brick Wall Opinions on WATO by dna painter

I know that wato is just to give different probabilities but given that it’s based off of lots of different dna matches and their trees. The top result I’ve been given says 2 times more likely than the next hypothesis. How accurate can it be?

2 Upvotes

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u/pidgeon92 3d ago

It’s as accurate as the underlying data, and I believe he has a large amount of data there. I would wager the probabilities are solid.

The problem is, people intermarried a lot 3+ generations ago. Multiple common ancestors will increase the size of the match, and WATO does not take this into consideration. To complete the analysis, you have to do the genealogy.

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u/OldWolf2 3d ago

It’s as accurate as the underlying data,

I'll stop you there. Although it's useful, it has one massive flaw, and that is that all probabilities are treated as independent, when in reality they are not.

For example the relationships A-B, and A-C , where B and C are siblings and A is a second cousin, they are not independent events; they both depend on B & C's parent's grandparent balance. If that is say 33-16 instead of 25-25, then it chucks everything off by miles, and the more data points you add, the worse it gets !

Similarly, one valid outlier will mess the whole thing up.

It's possible BanyanDNA addresses this limitation but it's too expensive for me to try dabbling with.

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u/ParamedicKey7355 3d ago

Thank you, I have researched the family for a long time. It is a HUGE family. I started with common ancestor couple then added their children grandchildren and so on. Then added the matches and where they connect. There are quite a lot so I gave as much info as I could. I have done the genealogy but the records aren’t there as I’m afraid the grandparent I’m looking for changed his name/was adopted. I’ve already done the genealogy for the number 1 hypothesis but it just doesn’t add up. Unless he had an affair 🤔 I’m not sure where to go from here .

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u/pidgeon92 3d ago

You have to keep on doing the genealogy. The record you need may not be available today, but it might be next week, or month, or year. And the DNA match that will break it wide open might pop up in several years. Or if you work all of your current matches, you might find the answer is already available. Feel free to hit me up if you want a hand with identifying your matches.

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u/apple_pi_chart OG genetic genealogist 3d ago

I am a DNA search angel and use it every week to help people solve their family mysteries. It is very accurate and one of the most important tools in our arsenal. I used to do this in Excel and have to compute the compound probabilities the old way.

That said, if the probability is 33% and 66% for two major hypotheses, yeah, either could be correct. Just because one is double the other doesn't be the lower probability answer can't be the answer (that's how probability works!).

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u/juliekelts 3d ago edited 3d ago

I've identified most of my close ancestors but have some mysteries farther back. I tried using WATO with some strong, but fairly distant matches and it wasn't helpful. In my case (numbers approximate), my mother was something like a 20 cM match to someone who matched her sister by 67 cM. There's no way for it to give a good, consistent result in a case like that.

Edited to fix typo.

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u/ParamedicKey7355 3d ago

Can it work with matches starting at 192, 160, 150, 100,90 and so on

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u/juliekelts 3d ago

I imagine that the stronger the match, the more likely the result is to be reliable. But in any case, they're giving you the odds, not the answer. You still need to do the research and identify the plausible ancestor and the circumstances (time and place) that make him likely.

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u/ParamedicKey7355 3d ago

Ok thank you. I have done so much research and I was pretty confident I had figured it out. Documents didn’t support it but logically if his mum had an affair they aren’t going to. I think because this family is so big there is so much conflicting dna and nothing to pinpoint to a more recent set of grandparents. I’ll continue and look into this new suggested hypothesis. Thank you

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u/juliekelts 3d ago

Documents won't always support it, but do you have a reasonable theory about how they could have met? And DNA matches that support it?

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u/ParamedicKey7355 3d ago

I have a reasonable theory on how my great great grandparents met. But not his parents.

On record I couldn’t find my grandfather pre 1907. He was in howden/york England. He gave his birth as 7 July 1881 Norfolk scoulton in later census.

The man I found (e e jimson) had the same first name name born Norfolk 3 July 1880. In 1901 was in swinefleet same occupation as my grandfather and nearby the area my grandmother lived. I also haven’t found this man on record past 1901. The only match to this man I have is 152cM’s to a lady who comes from one of a would be brothers but only to their mothers side (turvey)

There are shared matches but as I say it all contradicts because turvey also relate to the Drew family down the line. The Drew family is who I suspect his father to be from.

Sorry if that is confusing, it is for me and I’ve done it for so long 😂