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Anthropological significance of STR mismatches

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  • Anthropological significance of STR mismatches

    I have been wondering about this question for a long time. When my father's 37-marker results came back last year, it turned out that our family line - which could be traced back to Low German speaking shepherds in the Hamelin region around 1800 - belonged to haplogroup J2, with a very uncommon haplotype and no matches at the time, even at twelve markers.

    Of course the confusion was great and I'm poised to find out now how the heck the J2 got there, historically speaking. The Deep Clade test is under way, but I don't know how recent the origin of these subclades is estimated to be.

    On the other hand, you have FTDNA's MRCA estimations which operate with the term "relatedness" only for the last 1000 years at most. As far as our surname is concerned, our paper trail corresponds well with the name's distribution in the telephone directory, so I don't really have too many questions about recent times. Yet, the time period which really interests me, along with its corresponding genetic distance, does not count in terms of relatedness, according to the chart at FTDNA's site.

    What I would like to know now is what anthropological inferences can be drawn from STR results, as far as the time after the origin of subclades is concerned. What test covers the time between subclade SNPs and historically relevant STRs? If people with different surnames but the same haplogroup and subclade (other than R1b1 ) can be found in the same larger geographical area, say in different parts of Western or Central Europe, and they have a genetic distance of between 3 and 6, can any inferences be made about when in historical times a common ancestor might have arrived? About in situ variation after arrival, based on the number and geographical spread of almost-near matches?

    The latest comparisons in Ysearch returned a couple of interesting 12 marker mismatches. Is there anything anthropological to be inferred from say 3/12 mismatches with other J2s in Western Europe?

    Any suggestions would be highly appreciated.

  • #2
    Originally posted by anka
    I have been wondering about this question for a long time. When my father's 37-marker results came back last year, it turned out that our family line - which could be traced back to Low German speaking shepherds in the Hamelin region around 1800 - belonged to haplogroup J2, with a very uncommon haplotype and no matches at the time, even at twelve markers.

    Of course the confusion was great and I'm poised to find out now how the heck the J2 got there, historically speaking. The Deep Clade test is under way, but I don't know how recent the origin of these subclades is estimated to be.

    On the other hand, you have FTDNA's MRCA estimations which operate with the term "relatedness" only for the last 1000 years at most. As far as our surname is concerned, our paper trail corresponds well with the name's distribution in the telephone directory, so I don't really have too many questions about recent times. Yet, the time period which really interests me, along with its corresponding genetic distance, does not count in terms of relatedness, according to the chart at FTDNA's site.

    What I would like to know now is what anthropological inferences can be drawn from STR results, as far as the time after the origin of subclades is concerned. What test covers the time between subclade SNPs and historically relevant STRs? If people with different surnames but the same haplogroup and subclade (other than R1b1 ) can be found in the same larger geographical area, say in different parts of Western or Central Europe, and they have a genetic distance of between 3 and 6, can any inferences be made about when in historical times a common ancestor might have arrived? About in situ variation after arrival, based on the number and geographical spread of almost-near matches?

    The latest comparisons in Ysearch returned a couple of interesting 12 marker mismatches. Is there anything anthropological to be inferred from say 3/12 mismatches with other J2s in Western Europe?

    Any suggestions would be highly appreciated.
    Dear Anka,

    Regarding time calculations to measure the genetic distance or "relatedness" of two or more lineages, as you know, we have to rely on genetic mutations acting as molecular clocks.

    So far we only have SNPs and STRs to measure the ticks of genetic evolution, which extending the above analogy could be seen as the hour and minute hands in a real clock, respectively. (No seconds hand yet)

    Of course I'm oversimplifying everything for it is known that mutation rates are not constant and the values used to make calculations are statistically derived from very limited observations. Mutation rates even vary from one marker to another. So the best we can talk about when measuring TMRCA are only approximations to reality or plausible scenarios.

    May I suggest, if you haven't already done so, to visit McGee's Y-Utility and play around with your STR numbers; tweak the parameters a little here and there and see what output you get in terms of years to a common ancestor and genetic distances.

    Also, just in case you don't have these links among your favorites, here are two interesting URLs

    http://www.j2-ydnaproject.net/
    http://www.m410.net/yjdb/

    There you'll find plenty of haplotypes to compare to your dad's.

    V.

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    • #3
      Thank you Victor, I know all that and I am part of the J2-project already. I just want to be able to link historical migrations such as the expansion of the Hellenic or Roman Empire to STRs rather than SNPs only. Not many people have been subclade-tested yet, nor have these subclades been dated and put into a historical context. For the time after that, STRs are all we are left with.

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