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  • A Puzzle

    There used to be a "Grumbles and Gripes" section which I can't seem to locate now, so here goes on here.

    Has anyone else experienced this problem. A fellow project member upgraded his results from 37 to 111 on a Y-DNA test, and his results were posted to the said project. I assume this is done as an automatic function when the results come in. I copied his marker values from there and later by verification from his actual FTDNA results page which he senta copy of. In both instances the markers matched each other and clearly left me with a Genetic Distance 4. However, on my FTDNA matches it gives a GD of 5. This naturally affects the TIP report.

    I've queried it with FTDNA about four days ago but haven't received a reply. That leaves me not knowing if the results have been incorrectly entered or whether the GD figure is wrong. I would have thought this problem would be easy to see and rectify so four days seems a little excessive to me. Trouble is, if you are requested not to open a new ticket, how do you chase this up if in Europe?

  • #2
    How are you counting your multicopy markers

    https://www.familytreedna.com/learn/...romic-markers/

    If you post the values of each of your marker that differ, others may be able to see if GD of 5 is correct..

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    • #3
      A Puzzle

      Thank you prairielad

      The best way to do that is to direct you to the Wright Project

      https://www.familytreedna.com/public...frame=yresults

      Scroll down to Family Group 37 (in pink) RM-269

      The difference is between the first two men listed. I see a GD4, not 5 as FTDNA are saying.

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      • #4
        I looked at the project you are stating but Kit U4244 (tested 111) and the second kit, 267664 (tested to only 37?). Did you mean the 1st and 3rd kit, 273010? I count GD of 5 for those two kits. Comparing the last 2 kits ( last kit 351468)I get a GD of 4. And the only other combination of first to last I get GD of 3.

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        • #5
          Originally posted by Doublemartini View Post
          Thank you prairielad

          The best way to do that is to direct you to the Wright Project

          https://www.familytreedna.com/public...frame=yresults

          Scroll down to Family Group 37 (in pink) RM-269

          The difference is between the first two men listed. I see a GD4, not 5 as FTDNA are saying.
          I counted 5 for the first 2 men in Group 37.

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          • #6
            Originally posted by Doublemartini View Post
            There used to be a "Grumbles and Gripes" section which I can't seem to locate now, so here goes on here.
            Just to answer this, if you haven't already located it, the "Grumbles and Gripes" Subforum is listed last in the first section (Family Tree DNA Communications) on the main Family Tree DNA Forums page.

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            • #7
              Thanks KATM. That is also odd. When I click on your link, the page appears as I see it, but Grumbles and Gripes isn't mentioned. It is only listed as a sub-forum when going to the main page from there - but then that doesn't show the other categories!

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              • #8
                High734 and travers. Thank you both very much for looking. I'm not sure why I didn't give the kit numbers to make it clearer. The two kits in question are 409398 and U4244, which I tally as a GD 4, at markers 464d;456;570;532. FTDNA give a GD5.

                A newly arrived result today for kit 647734 also has a disparity with kit 409398, where I see a GD 6 but FTDNA gives 7.

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                • #9
                  Their 532 is counted as two steps. One has a 14 and one has a 16. So this single marker will produce a genetic distance of 2.

                  -Darren

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                  • #10
                    Thank you very much Darren, and other respondents. That is very interesting. I hadn't realised that. A fundamental gap in my understanding rectified! Not having access to the GD differences for kit 409398 across the group, It only appeared as a "problem" with my kit initially and then, the other kit I manage. It obviously impacts on others GDs across the group which, of course, I wasn't aware of.

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                    • #11
                      I thought I'd heard that FTDNA was going to stop counting the steps at a single marker because recent evidence suggests that a two or more step difference can happen as a single mutation event.

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                      • #12
                        Even if it is more likely that a difference of two or more steps occurred through a single "mutational event", it does not follow that a one-step event and a multi-step event are equally likely. If they are not, the "genetic distance" may turn out to consist of units that are not the same size, so that it is not appropriate simply to plug the genetic distance value (for example, 4) into a formula that assumes each "step" in the genetic distance had the same probability of occurrence. The predictions would be distorted to the extent that the genetic distance consisted of units of different probabilities. An interesting conundrum.

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                        • #13
                          I don't have any information on when or if they may decide to change how genetic distance is updated. If I hear anything I will let you know though.

                          -Darren
                          Family Tree DNA

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                          • #14
                            Originally posted by DaveInGreece View Post
                            I thought I'd heard that FTDNA was going to stop counting the steps at a single marker because recent evidence suggests that a two or more step difference can happen as a single mutation event.
                            Even if they announce a change it is often not implemented. For example last July they announced that from that point on null values would only be counted as a difference of one. That change was never implemented into the matching algorithm as I have project members who should show as matches to each other that don't because of a null value.

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