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4 Different surnames with GeneticDistance=0 (12 markers). How could that be ?

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  • 4 Different surnames with GeneticDistance=0 (12 markers). How could that be ?


    I have a question that will sound trivial for a lot of people ... but not for me

    But first, a few points :
    1)I got results from Y-DNA 37 markers and the results were :
    -0 match for 37 markers
    -1 match for 25 markers (Genetic Distance =2) : 1 match from Holland
    -3 matches for 12 markers (Genetic Distance = 0) : 2 from England and 1 from Scotland
    -17 matches for 12 markers (Genetic Distance = 1)

    2)My 3 matches (12 markers) with GeneticDistance=0 are individuals with 3 different surnames.
    The Dutch individual with GeneticDistance =2 (with 25 markers) has a GeneticDistance =1 for 12 markers.

    3)According to the 3 individuals, their EKA (earliest known ancestor) come from Scotland (circa 1676) or England (circa 1780)

    4)On my side, my EKA comes from France (circa 1600). All my paternal ancestors lived in QC, Canada for the last 400 years. My surname is typical of French Surname.

    My question :
    According to the TIP report, there is 91% chance that the 3 individuals (with genetic distance =0 for 12 markers) and me share the same EKA around the 24th generation (circa the years 1200 - 1300, I presume)

    So, there are 3 different English surnames and 1 French surname for a common ancestor around the 24 generation.
    I understand that it could be a NEP event (non parental event) situation : it would mean that 4 individuals (3 English and 1 French surnames) would have inherit their surname from 4 different NEP ?

    Could anyone help me out in this puzzle ? To explain that 4 different surnames could share the same EKA ? A bit of explanation about my match (Genetic Distance=0 with 12 markers) with 3 individuals (the four of us have different surname) would be appreciated


  • #2
    12 markers isn't enough to tell you much of anything. I have people in my projects with over 1,000 12 marker matches and many different surnames. All you really know is that they have a common 12 marker Haplotype.

    12 markers can tell you two people aren't related, but it can't tell you they are related.


    • #3
      The TiP report, of course, is only an estimate of the probabilities, based on a number of untested assumptions. Even if it happened to yield a close approximation of the actual distribution of probabilities for a large sample of men of European ancestry, that would not necessarily mean that it is anywhere close to the truth for every individual.

      A more basic issue is the assumption that surnames and nationalities necessarily align with the Y-DNA results. Surnames in many parts of Europe turn out to have been far less stable than most people imagine. Certainly as late as the 16th Century there were areas, including France, where families were known by more than one name (in Quebec, you know about "dit" names), and where different branches of the same family eventually ended up using different surnames. The farther back you go, the less stable surnames were. Sticking with the French experience, too, there was a certain enormous migration of French families "scattered to the winds", and ending up all across Europe, the New World, South Africa, and a few places even more remote than that. Their French surnames sometimes morphed into something nearly unrecognizable if they happened to end up in the British Isles, the Netherlands, or Germany. And that was only one of the large-scale migrations. Many families in all the place you named have very diverse roots, and that is likely to be reflected in Y chromosomes as well.

      The Y chromosome patterns (the STR's and SNP's reported by FTDNA) probably existed long before the surnames had stabilized and long before many of the migrations that made Europe so interesting today. So it is not unusual to find multiple surnames and national origins among the Y DNA results.


      • #4
        thanks for the detailed answers

        Hi Jim and John

        Many thanks for your detailed answers : it is very appreciated.

        Ok, I think (hope!) that I have a clearer understanding of my 12 markers results (included in my Y-37 set).

        So, if I conclude :
        i)having 12 markers non-match with other individuals will help identify individuals that are not closely related.
        For instance, my surname is Bonhomme.
        The first Bonhomme came in New-France around 1637 (Nicolas Bonhomme (circa 1603-1683), m. Catherine Goujet). I am his descendant at the 11th generation.
        At first sight (surname comparison), I thought that the Bonhomme and the Bonham would be related. By analyzing my 12 markers and their 12 markers, it looks like that the genetic distance is too high between us.
        So the 12 markers help me out for that occasion

        ii)TIP report and stats. OK, I will accept the fact that surnames can vary a lot during the last 1000 years for the descendants of the same ancestor. And I will be more cautious when I read "91.4% - 24 generations" for an ancestor that me and another individual share.
        24 generations would bring us in the year 1100-1200-maybe 1300 (assuming 3 generations per century : 3x8=24 generations). I should not 'stick' with this number and most probably, our common EKA (for me and the 3 other individuals (English and Scot)) may have lived before the year 1000.

        John : you are totally right about the "dit" names in Quebec.
        My ancestor Nicolas Bonhomme came in North-America without any nickname. Howewer, descendants of two of his sons abandoned the surname Bonhomme to take the surmame Beaupré (Bonhomme dit Beaupré) and the surname Dulac (Bonhomme dit Dulac); after a few generations, Beaupre and Dulac stayed but Bonhomme disappeared for those descendants.
        Most of the living male descendants of Nicolas Bonhomme are now Beaupré, Bonhomme being quite rare : My Bonhomme ancestors had more daughters than sons.
        On top of that, some descendants of Nicolas Bonhomme (m.Catherine Goujet) in North-America change their name to Bonum and Goodman.

        I found no possible match in Y-search and in FrenchHeritage group (that I am a member of).
        For the moment, I am asking some living men Beaupré, Dulac & Bonhomme (who are fond of genealogy) to buy a Y-DNA-37 test. Maybe Y-triangulation to Nicolas Bonhomme (m. Catherine Goujet) will then be possible.
        I am also trying to find some Bonhomme candidates in UK or in France to participate (there are Bonhomme in Netherlands as well).

        Thanks again