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A New Relationship Predictor for Genetic Genealogy

Discussion in 'DNA Questions and Answers' started by Kane133, Mar 18, 2024.

  1. Kane133

    Kane133 LostCousins Member

  2. Pauline

    Pauline LostCousins Megastar

    I've just had a quick play around with this and I'm not sure how much more helpful it is than other relationship predictors though I can see that their various graphs are showing an improvement. However, I tried it with one of my matches who is a documented half second cousin with whom I share 137 cM over 5 segments, and half 2C falls into the most likely group at 52.8%. However, my sister shares 322 cM over 11 segments with this cousin and half 2C falls into the lowest probability group at only 0.7%.

    I then tried the sibling option where I could run the above search with the DNA details entered for both me and my sister. This time half 2C fell into the second most likely option at 20.6%.

    I then tried an unknown match with whom I share 267/12 and my sister 206/9. On the search using both I came up with an 84.9% chance of the match being in the 2nd cousin group. For me alone it was the same group at 61.9% and for my sister the same group at 77.9%.

    So where does that leave me? The 2nd cousin group includes 2C, 1C2R, Half-1C1R, Half-2G-Aunt/Uncle/Niece/Nephew, which is quite a range in itself, but from my experience with the known match, I can't necessarily rely on the most likely group being the right one. So I'm not really any more the wiser about my relationship with the unknown match than I was from the Ancestry predictions.

    Anyway, that's my experience for what it's worth.
    • Agree Agree x 1
  3. peter

    peter Administrator Staff Member

    There was a paper about this around a decade ago. In practice there are usually other factors, such as age difference, that enable us to differentiate more confidently between close relationships which typically share a similar amount of DNA.

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