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Understanding likelihood of relationship based on matching at different testing level

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  • Understanding likelihood of relationship based on matching at different testing level

    Hi, I did a 67 marker Y-DNA test. There are NO matches reported at the 67 or 37 marker testing level. However, there are five matches, all at a distance of 2, showing up at the 25 marker level. The TIP report for these says that there is a 61 % chance of a common ancestor 4 generations back. This is quite a lot! However, given the complete lack of matches at the 37 and 67 marker level, I am not sure how to interpret these. Most of the matches tested at the 67 or 111 marker level. Does the lack of matches to these individuals at the higher level of testing indicate that the common ancestor with these matches is much more distant? Also, I have seen in other threads that people were reporting erroneous match results back in 2013 (where they were seeing 25/37 marker matches that they KNEW were close matches and yet were seeing no matches at the 67 or 111 level). Is this still going on? Could this be a reason for my odd results?

  • #2
    Did your matches only test 25 markers? If they tested 37 or 67 markers and there is no match at that level, I would ignore the fact that they matched at 25 markers.

    If your matches did not test 37 or 67 markers, there is a possibility that those matches are meaningful. However, matches as 12 or 25 markers are very unreliable.

    I would ignore the TiP probabilities. Any match is going to show fairly high TiP probabilities even though a lot of matches do not reflect a close relationship. TiP reports routinely show very high probabilities for unrelated people.
    Last edited by TwiddlingThumbs; 10 March 2018, 08:02 AM.