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Small X but FF says 2-4 cousin

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  • Small X but FF says 2-4 cousin

    Hi

    I am puzzled as to how close a match is.
    Family Finder says the CA is within 2-4 cousin with a shared cM of 61.56 (longest block 23.80).
    However, the block on the X is only 1.5 cM suggesting a CA far far back.

    What is your take?

  • #2
    The longest block seems quite OK to me. The rest of the values are not big. Probably you and your match are not from one single rural population or something like that.

    Based on the size of all autosomes compared to X chromosome and thus the much larger statistical weight of autosomes, I would just forget the X matching for now. If you find a common ancestor who fits the X inheritance pattern, the X matching is still a tiny plus to the proof.

    X-matching has much deeper reach to ancestors than autosomal matching usually has. Even if the X block is IBD and not IBS, then good chances are that it may be a result of much more distant connection than the closest autosomal connection is.

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    • #3
      Originally posted by klajsdfkjlkjlkjs View Post
      Hi

      I am puzzled as to how close a match is.
      Family Finder says the CA is within 2-4 cousin with a shared cM of 61.56 (longest block 23.80).
      However, the block on the X is only 1.5 cM suggesting a CA far far back.

      What is your take?
      The fact that you have at least one segment above 7.0 cM means you are related to the match. So, this match is a cousin, but not because of the small segments.

      I disregard all segments below 5.0 cM that FTDNA counts. They're at least as likely to be a false positive as a segment you and the match received from a common ancestor.

      How many of the segments with this match are above 5.0 cM? How many above 7.0 cM? What's the total of cM for the segments above 5.0 cM?
      Last edited by MMaddi; 11th September 2015, 08:57 AM.

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      • #4
        I dont think FF even considers X DNA when making relationship estimates.

        I have a cousin with the following cM
        Autosomal Total 44 with longest block of 8
        X Total of 61 with a longest block of 49

        If the X data was included, I think I would be considered 2nd to 3rd.

        Yet we are only estimated as 5th to Remote, which is actually fairly close

        She and I are double cousins. 5th and 5th,1R

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