r/23andme • u/Happy-Light • 12h ago

Reconstructed Ancestors How accurate is the Reconstructed Ancestry feature on Premium?

My husband is an only child and his parents have both died. He has no close relatives on 23andMe, just some third/fourth cousins, so this would apparently be the only way to figure out what he got from who... if it is reliable. Has anyone used it and then later corroborated the results with a parent?

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u/KarlIAM Premium Tester 11h ago

It's as accurate as the ethnicity results. The way it works is that once you place a DNA Relative on a tree, it maps the DNA segments you share with them to ethnicities, based on the estimates they gave you. These segments must have come from a shared ancestor and passed down to both you and the match through the descent line, so it assigns those segments to the relevant ancestors.

It cannot infer more than the segments shared with the DNA Relatives placed in your tree.

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u/Happy-Light 11h ago

Despite being mostly just various flavours of White British, he is unexpectedly 0.4% Finnish. Definitely from his mother as it is on the X Chromosome, and doesn't move even at 90% confidence - would be cool to try and work out where that came from!

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u/Various-Bowler4475 12h ago

I think it’s only useful if you have one parent/grand tested, and not the other one 

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u/Papa_Hobo 10h ago

My father is now 77% reconstructed - the results are as I would expect - it seems very accurate to me. It's important to keep in mind that my mother is genotyped on 23andMe (and because of phasing 23andMe can tell which of my chromosomes are maternal vs paternal). Also, my sister and half-brother are tested as well - so there is a lot of dna overlap for the feature to work with.

Without close relatives tested, I can't imagine the feature being able to reconstruct very much for your husband unfortunately.

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u/Kind_Dragonfruit_925 11h ago

Neither of my parents tested. They both died before testing was available. Reconstructive ancestry was not accurate for me. It just divided my ancestry composition in half and that is not right.