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  • Margin Of Error

    Could someone please tell me the margin of error that could take place in the Y-DNA 25 marker test. I match to others in my surname group 24 out of 25 markers. Is it possible that FTDNA could have misread my test results?

    Thanks,

    Mike

  • #2
    A mutation can take place at any time between generations. There are a few people on this forum who have a 24/25 match with their own father. Other families have not seen any mutations for 15 generations. If there is a good paper record linking you to people with the same surname, a 24/25 match is certainly strong enough to confirm that you are related.

    John

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    • #3
      Originally posted by Mike Mallett
      Could someone please tell me the margin of error that could take place in the Y-DNA 25 marker test. I match to others in my surname group 24 out of 25 markers. Is it possible that FTDNA could have misread my test results?
      I think you mean "possibility of error" not "margin of error".

      Mistakes are always possible, but verified errors are pretty uncommon. What makes you suspect error in your results? Your results would seem, at first glance, to be expected.

      Comment


      • #4
        John, Thanks for the reply. We have a paper trail, so I know that we are related. My question is could FTDNA have made a mistake on reading the marker we are different on?

        Thanks,
        Mike

        Comment


        • #5
          "I think you mean "possibility of error" not "margin of error"."
          Thanks Vineviz, That's a better way to put it. So, how easy is it for a mistake to happen when they read the results?

          Thanks,
          Mike

          Comment


          • #6
            Originally posted by Mike Mallett
            John, Thanks for the reply. We have a paper trail, so I know that we are related. My question is could FTDNA have made a mistake on reading the marker we are different on?

            Thanks,
            Mike

            I would check your paper trail.

            I found so many errors that have been made over the years..

            I wonder if Utah still shows my Grandfather as a female. (They were notified and they just added my information, and left the bad information).

            Or my great grandmother having two sets of parents..

            d

            Comment


            • #7
              Originally posted by Mike Mallett
              John, Thanks for the reply. We have a paper trail, so I know that we are related. My question is could FTDNA have made a mistake on reading the marker we are different on?
              As I said, I think it is possible but the odds are very, very low. You would need some sort of comprehensive survey to determine exactly how low, but suffice it to say that you probably do not have a mistake.

              Since you have a paper trail and the DNA confirms the paper trail, I'm not sure I see what would be gained by worrying about it. You could always pay to have that marker tested individually under the "Advanced Tests" option to see if you get the same result.

              Better yet, each of the involved parties could find additional relatives (cousins, uncles, etc.) for testing so that you could determine in which generation the mutation developed.

              Or, if you are simply wanting stronger evidence, you could each upgrade to 37 markers.

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              • #8
                Thanks Vineviz, I did not know that I could have that marker retested.

                Mike

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                • #9
                  Mike,

                  As you have already been told there is no reason to expect an error in your case. Bennett Greenspan isn't an exact match with his father. One or more mutations can occur every generation.

                  Comment


                  • #10
                    Thanks Jim, I guess I'm just one of those guys who wants to know when the mutation took place if possible. I have found someone about five generation back, that is in my line, willing to submit his NDA. Maybe he will be a perfect match with me. I know it doesn't matter. I just want to know if possible.

                    Thanks to all that Posted,

                    Mike Mallett
                    Last edited by Mike Mallett; 8 February 2007, 03:50 AM.

                    Comment


                    • #11
                      If you are not an exact match with your father, didn't the mutation just occur with you? How could it have occurred previously? Are you thinking you might look like a prior generation, before your father, that he mutated and you mutated back to an earlier state? That seems unlikely.

                      Whenever a mutation first occurs, it is between 2 directly connected generations. It doesn't happen a little at a time.

                      It also doesn't mean that your line mutates more frequently. There might not have been a previous mutation for 1,000 years. You just happen to be the mutation. That is actually very interesting, to be able to observe an actual mutation. By testing others in the line you would be able to see if there are other mutations, and then know better if mutations occur frequently in your line.

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                      • #12
                        Kaybee, Thanks for the reply. I guess I haven't made myself clear. I know without a doubt that I am related to the other members in my study group. We go back nine generation to a common grandfather. What I'm trying to determine is where the mutation took place. My father died in 1980, so I don't have a sample of his DNA. He had brothers but they had no male descendants. My grandfather died in 1943 and he had no brothers. My great-grandfather died in 1914 and he had no brothers. My great-great grandfather had two brothers but there is no living male descendants. My great-great-great grandfather had brothers and there is male descendants. I have located one that is willing to be tested. So, if he doesn't match me then I guess it will be impossible to determine where the mutation took place between me to my great-great grandfather. I know this really doesn't matter but as a genealogist, I want all the "i's" dotted & "t's" crossed that I can get. We are in the infancy of this DNA testing and there is no telling what the future will hold for our descendants.

                        Again, thanks for all the replys,

                        Mike Mallett
                        Last edited by Mike Mallett; 8 February 2007, 11:01 AM.

                        Comment


                        • #13
                          Originally posted by Johnserrat
                          A mutation can take place at any time between generations. There are a few people on this forum who have a 24/25 match with their own father. Other families have not seen any mutations for 15 generations. If there is a good paper record linking you to people with the same surname, a 24/25 match is certainly strong enough to confirm that you are related.

                          John
                          We have to understand that mutations (rare) are passed on to offspring.
                          If my father has a (Y-DNA tested) mutation, it will be passed on to me through his genes.
                          This is the way it works.
                          d

                          Comment


                          • #14
                            Y-Chromosome DNA marker mutation rates.

                            The following site lists the various mutation rates and shows that the 13-25 markers have, on average, a slightly higher mutation rate than the 1-12 makers, but the individual rates are very variable.

                            http://www.worldfamilies.net/marker.htm

                            My "problem" is slightly different to yours. I'm Haplogroup N3a, but I seem to be the only one in the world (tested so far) that has DYS437=15. Everybody else have DYS437=14. I also thought that FT had made a mistake in reading the test results, but the value has now been verified by the SMGF testing so it is most certainly correct. DYS437 is a very slowly mutating marker so DYS437=14 is most probably the original value at the time of the M178 SNP mutation, i.e. the start of the N3a Haplogroup. Somewhere in my patrilineal ancestry, maybe with me, did the 14 to 15 mutation take place. I'm now trying to get other patrilineal relatives to take the STR test to find out.

                            PS. I have found one other N3 with DYS437=15, but he and I have a Genetic Distance of over 10 so we are not related so he, or his patrilineal ancesters, have, independantly, also had the same mutation.

                            Comment


                            • #15
                              Originally posted by Mike Mallett
                              Could someone please tell me the margin of error that could take place in the Y-DNA 25 marker test. I match to others in my surname group 24 out of 25 markers. Is it possible that FTDNA could have misread my test results?

                              Thanks,

                              Mike

                              EVEN MORE when the names in study are close the majority i have seen had substantual differences maybe a couple of markers here and there. you dont have to exact matches to all the others
                              actualy these can show where branches broke of the tree trunk aka migrations to the states or big cities

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