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Significance of the number of markers tested.

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  • Significance of the number of markers tested.

    Been educating myself but still don't get the significance of the number of markers tested I just read in one of the comments that 12 marker matches would indicate a distant relative of 10,000 years. And the perception I got was that the larger number of marker matches would indicate closer matches of 1,000 or less.
    Insight would be greatly appreciated.

  • #2
    Originally posted by sshayward View Post
    Been educating myself but still don't get the significance of the number of markers tested I just read in one of the comments that 12 marker matches would indicate a distant relative of 10,000 years. And the perception I got was that the larger number of marker matches would indicate closer matches of 1,000 or less.
    Insight would be greatly appreciated.
    Tell us more about the question(s) you want answered .

    In general, more STR markers mean matching with more confidence. However, mutations do happen..., that is even from father to son there could be a mutation at some point time.

    Consequently, many people purchase either Y-DNA37 or Y-DNA67 test, and followup with the Big Y test (of course the other party has to purchase the Big Y test or an equivalent test too).

    W. (Mr.)

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    • #3
      Originally posted by sshayward View Post
      Been educating myself but still don't get the significance of the number of markers tested I just read in one of the comments that 12 marker matches would indicate a distant relative of 10,000 years. And the perception I got was that the larger number of marker matches would indicate closer matches of 1,000 or less.
      Insight would be greatly appreciated.
      Different markers mutate at different rates. The first 12 markers mutate very slowly and are highly reliable for predicting a major haplogroup designated by an SNP that first appeared more than 10,000 years ago. For the dates of some haplogroups and their dates see the table from a recent study at http://www.nature.com/ncomms/2015/15...ms8152_T1.html and drill down in the YFull tree at http://www.yfull.com/tree/

      The people that match you at 12 markers happen to have markers that mutated the same as your paternal line but due to convergence they have the exact same markers that you do. Since you also belong to the same haplogroup you have a common ancestor that first had the SNP for that haplogroup. Within that list of 12 markers matches some could be related to you in a genealogical time frame but both you and those matches have to test more markers to determine if that is the case. A lot of the other markers that can be tested by FTDNA mutate faster and therefore there is a higher likelihood that you share a common ancestor more recently than the past 10,000 years for close matches at 67 and 111 markers. A majority of the time a close match at 67 markers is from a common ancestor in the past 500 years but there are rare occurrences that it is in the past 1,000 years.

      For instance I have almost 200 matches at 12 markers. The only way for me to know which matches are significant I need to look at matches with more markers. At least half of those people have had a 25 marker test. Only 16 people match me at 25 markers but most aren't even from the region of my most distant ancestor. Half of those people have had a 37 marker test but only 2 people match me at 37 markers. One is from my region and one is from the other side of the border from my region. Only one of those still matches me at 67 and 111 markers. That person also shares my surname and his ancestors are from the same town as mine. I have zeroed in on a significant match which could be from more than 500 years but less than 1,000 per the TiP report and no common ancestor in the past 10 generations.

      For another example of someone not seeing significant matches until 111 markers see Mike W.'s post at https://groups.yahoo.com/neo/groups/.../messages/2435

      Since markers mutate randomly the matching and the time to the most recent common ancestor varies. To see the mutation rates of various markers see http://en.wikipedia.org/wiki/List_of_Y-STR_markers
      Last edited by Armando; 24 May 2015, 04:54 PM.

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      • #4
        Helped so much!

        Originally posted by Armando View Post
        Different markers mutate at different rates. The first 12 markers mutate very slowly and are highly reliable for predicting a major haplogroup designated by an SNP that first appeared more than 10,000 years ago. For the dates of some haplogroups and their dates see the table from a recent study at http://www.nature.com/ncomms/2015/15...ms8152_T1.html and drill down in the YFull tree at http://www.yfull.com/tree/

        The people that match you at 12 markers happen to have markers that mutated the same as your paternal line but due to convergence they have the exact same markers that you do. Since you also belong to the same haplogroup you have a common ancestor that first had the SNP for that haplogroup. Within that list of 12 markers matches some could be related to you in a genealogical time frame but both you and those matches have to test more markers to determine if that is the case. A lot of the other markers that can be tested by FTDNA mutate faster and therefore there is a higher likelihood that you share a common ancestor more recently than the past 10,000 years for close matches at 67 and 111 markers. A majority of the time a close match at 67 markers is from a common ancestor in the past 500 years but there are rare occurrences that it is in the past 1,000 years.

        For instance I have almost 200 matches at 12 markers. The only way for me to know which matches are significant I need to look at matches with more markers. At least half of those people have had a 25 marker test. Only 16 people match me at 25 markers but most aren't even from the region of my most distant ancestor. Half of those people have had a 37 marker test but only 2 people match me at 37 markers. One is from my region and one is from the other side of the border from my region. Only one of those still matches me at 67 and 111 markers. That person also shares my surname and his ancestors are from the same town as mine. I have zeroed in on a significant match which could be from more than 500 years but less than 1,000 per the TiP report and no common ancestor in the past 10 generations.

        For another example of someone not seeing significant matches until 111 markers see Mike W.'s post at https://groups.yahoo.com/neo/groups/.../messages/2435

        Since markers mutate randomly the matching and the time to the most recent common ancestor varies. To see the mutation rates of various markers see http://en.wikipedia.org/wiki/List_of_Y-STR_markers
        Thanks Armando, your explanation helped so much as I do have similar results.

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