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  • genetic distance 0

    Dear all,

    FTDNA gives me different persons with genetic distance 0 at 12 Markers...

    Should I contact them in every case eenthough they don't show a genealogical tree on the website?



  • #2
    To what level did your male relative test? Was it only to 12 markers, or to something higher, such as 25, 37 or 67 markers?

    If tested to a higher level, see if any of the 12 marker matches continue to match, and contact those. Matches at 12 or even 25 markers are unlikely to be related in a genealogical timeframe, where you could find out your common connection.

    Most advice for Y STR testing is to test at least at the 37 marker level, even 67. You will get fewer matches at the higher levels, but they will have an increasing chance of being related within a genealogical timeframe. See the chart in the FTDNA Learning Center, for Paternal Lineage Tests, under the heading "The Science of Your Direct Paternal Line." It shows the different probabilities for the number of generations ago that a common ancestor lived, by percentage.

    For example, the chart shows that for a Y-DNA 12 marker test with a match with Genetic Distance of 0, there is a 95% probability that the common ancestor would be 29 generations ago. That is roughly something like 700 years or so, and few people can trace their ancestors that far back. Compare that with a 0 genetic distance at Y-DNA 67 markers: a 95% probability that the common ancestor would be 7 generations ago, perhaps less than 200 years; it's much more likely to determine a common ancestor at that level of testing.


    • #3

      I have the family name Audubon appearing up at 25-marker (genetic distance 2), 37-marker (genetic distance 3) and 67 marker (genetic distance 3).

      It doesn't appear at the 12-marker and 111-marker.




      • #4
        I'm not a Y-DNA specialist, so others may chime in. I'm inferring from what you wrote to mean that you have tested to 111 markers.

        You could try contacting the match at 67 markers with genetic distance of 3. If they have a tree, see what you can find. Contact them in any case, to see if you can find any common locations and ancestors. Maybe they'll reply, and perhaps they have a tree posted online elsewhere that you can check. It would be a better match if they continued to match at 111 markers, though.

        Is Audubon a surname in your ancestry?


        • #5
          I personally do not pay attention to 12 and 25 marker matches. It's just too few STRs to really feel confident about.

          It is also worth noting that even at the higher marker counts (37,67,111) you can sometimes have matches that aren't related to you for thousands of years. I have matches who are distances of 2,3,4 in the 37 marker range who remained fairly close on 67 markers, dropped off entirely at 111 markers and through Big Y I learned I'm not related for thousands of years and I am instead related (estimated common ancestor lived 1,700-1,800 years ago) to two people who aren't even in my 37,67,111 marker match lists!

          I firmly believe that SNP testing combined with STRs is a better approach to genetic genealogy on the paternal line vs. STRs alone.