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DNA Origins interpretation

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  • DNA Origins interpretation

    Approx how many generations (or years) back is the 'Origins' snapshot taken?
    My DNA "Origins" have good correlation with my paper trail.

    Paper trail - Ireland, England, Scotland, Czech Rep.
    Family Finder "Origins" British Isles, Scandinavia, Iberia, East Europe
    Y DNA 67 "Ancestral Origins" : Ireland, Scotland, Germany

    Reading history of the Vikings and migration of Basques into British Isles things seem to fit but it would be nice to know how far back the "Origins" sits in time.

  • #2
    The MyOrigins results are based on the Family Finder autosomal DNA data. The autosomal DNA data are compared with "reference" samples from modern (likely still living) people who have been selected (by statistical methods, hopefully) in such a way that they form "clusters" or genetically similar group that are believed in some way to "represent" particular ethnic populations.

    A big assumption that comes with this approach is that the "reference groups" (clusters of genetically similar modern people) are assumed to represent historical populations that have been interbreeding without significant in-migration for some indefinite period of time, long enough to have mixed the SNP's to the point where any original linkage relationships have been scrambled. However, since the actual historical DNA samples are not available, these assumptions cannot be tested, and attaching a date to the origins of any "population" that is inferred from the modern samples is mainly a thought experiment.

    While the statistical approach of detecting clusters of genetically similar modern samples is real, the significance attached to these clusters (by labelling one of them as "Scandinavian", for example) is more arbitrary.

    A further complication is that, as a result of recombination and the random assortment of homologous chromosomes, YOUR own DNA will probably not reflect the percentages of ethnic ancestry (whatever ethnic means, another question altogether) that you would calculate from your paper trail. Some of your ancestors will likely be significantly under-represented in your DNA, and others over-represented, with the result that even if the "reference groups" were exactly accurate both in the SNP's that they contain and in their labels, your ethnic origins results would still not match your pedigree closely.

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    • #3
      Thanks John - appreciate your excellent outline. I am confident my rigorous cross checking of paper trail but somehow hoped my DNA results would help confirm. Now not so sure it's going to help until with luck a distant relative emerges that we connect paper trail and DNA. This is going to be a long shot as my ancestors on mothers & fathers side were decimated by illness during the Irish famine and I'm here courtesy of 2 young men who emigrated 1850 -52.

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