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Thread: GEDMatch vs. commercial companies

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    GEDMatch vs. commercial companies

    Two questions:

    (1) It's my understanding that certain GEDMatch calculators (like Eurogenes K36) focus on much deeper ancestry than those used by commercial companies. How is this achieved? Do the Dodecad calculators also focus on deeper ancestry?

    (2) I constantly hear/read that the many tools on GEDMatch can give you "more detail" on your ancestral background than most commercial companies can. But if many of the GEDMatch calculators focus on deep ancestry while most commercial companies focus on more recent ancestry, that's not an accurate characterization, is it? Aren't we then comparing apples to oranges (i.e., deep ancestry vs. recent ancestry)?

    My apologies in advance for asking what are surely very basic questions. I'm new to the site and I have absolutely no background in genetics, but I'm fascinated by the field and I'm hopeful that the knowledgable community here can provide some guidance.

    Thanks!

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    As I understand it the focus on deeper ancestry claim or the "Our test goes back X number of years/generations" are all basically false claims because most tests use modern reference populations. An exception that I can think of to this is would be something like Tolan's ancient genome comparison calculator: http://gen3553.pagesperso-orange.fr/ADN/ancient.htm as this actually tests your DNA against ancient samples. This is done using your GEDmatch scores from Eurogenes k36.
    From what I can tell, a commercial company like Ancestry claiming "Thousands of years ago" under their ethnicity estimate is misinformation, and is used as a claim to cover their bases for when a customer receives results which don't match their known genealogy. They tell these customers that their results don't make sense because their test goes back X number of years, and use that as an explanation. In truth, it is more likely because the samples the company has collected are low in number, inadequate, or both. These companies are comparing your DNA against samples from living people (or people which were alive when the samples were collected, so that would have to have been recently) they have collected in order to gain your ethnicity estimate, so I don't think it is right that they feel they can claim to go back "thousands of years". This is especially funny because the categories used by Ancestry DNA feature names of modern countries, and then they make the claim that their test detects your ancient admixture.

    That said, there are calculators on GEDmatch and elsewhere that compare your DNA to ancient samples and show you your genetic makeup in terms of things like Hunter Gatherer, Neolithic Farmer, and Steppe ancestry. FTDNA has a feature called "Ancient Origins" which does this, but I think it is much worse than the options available on GEDmatch and elsewhere.

    I think in terms of recent ancestry 23andme is the one that can give you the most detail; They appear to be able to assign small amounts of DNA, less than one percent, with some degree of accuracy and confidence. As for the accuracy of K36 on Eurogenes, my guess is that it uses more categories and possibly has a greater reference population / data set but I haven't looked into that. There are people on this forum who make some truly fantastic tools and calculators with K36 and I'll wait for them to answer that one for you
    Last edited by sktibo; 08-09-2017 at 02:15 AM.
    Paper trail ancestry to the best of my knowledge:
    English 28.12%, East German or Eastern European 25%, Scottish 17.96%, Irish (mostly lowland Scottish origin) 12.5%, French 8.2%, Welsh 3.125%, Native American 1.95%, and Colonial American, 3.125%, which cannot be determined with complete certainty: there is Dutch (at least 1.36%) and some English. The rest could include Spanish, Norwegian, German, and French, but these percentages would be minuscule.

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    Quote Originally Posted by sktibo View Post
    As I understand it the focus on deeper ancestry claim or the "Our test goes back X number of years/generations" are all basically false claims because most tests use modern reference populations. An exception that I can think of to this is would be something like Tolan's ancient genome comparison calculator: http://gen3553.pagesperso-orange.fr/ADN/ancient.htm as this actually tests your DNA against ancient samples. This is done using your GEDmatch scores from Eurogenes k36.
    From what I can tell, a commercial company like Ancestry claiming "Thousands of years ago" under their ethnicity estimate is misinformation, and is used as a claim to cover their bases for when a customer receives results which don't match their known genealogy. They tell these customers that their results don't make sense because their test goes back X number of years, and use that as an explanation. In truth, it is more likely because the samples the company has collected are low in number, inadequate, or both. These companies are comparing your DNA against samples from living people (or people which were alive when the samples were collected, so that would have to have been recently) they have collected in order to gain your ethnicity estimate, so I don't think it is right that they feel they can claim to go back "thousands of years". This is especially funny because the categories used by Ancestry DNA feature names of modern countries, and then they make the claim that their test detects your ancient admixture.

    That said, there are calculators on GEDmatch and elsewhere that compare your DNA to ancient samples and show you your genetic makeup in terms of things like Hunter Gatherer, Neolithic Farmer, and Steppe ancestry. FTDNA has a feature called "Ancient Origins" which does this, but I think it is much worse than the options available on GEDmatch and elsewhere.

    I think in terms of recent ancestry 23andme is the one that can give you the most detail; They appear to be able to assign small amounts of DNA, less than one percent, with some degree of accuracy and confidence. As for the accuracy of K36 on Eurogenes, my guess is that it uses more categories and possibly has a greater reference population / data set but I haven't looked into that. There are people on this forum who make some truly fantastic tools and calculators with K36 and I'll wait for them to answer that one for you
    Thanks so much, sktibo. In fairness, I believe Ancestry claims that its results date back "hundreds of years, and potentially 1,000 years" (or something like that). I take this to basically mean that after a couple of hundred years, your ancestors' immediate contributions to your DNA are minimal (the number of ancestors doubles with each generation), and thus, that's roughly where the line is drawn.

    I look forward to hearing more thoughts on the GEDMatch calculators, though. I'm particularly curious to hear thoughts on the Eurogenes K36 mapping tool that drops you on a certain point on the map. Is that really just "fun," or is it telling us something meaningful (and does it relate to recent or distant ancestry)?

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    Quote Originally Posted by Apex n Harmony View Post
    Thanks so much, sktibo. In fairness, I believe Ancestry claims that its results date back "hundreds of years, and potentially 1,000 years" (or something like that). I take this to basically mean that after a couple of hundred years, your ancestors' immediate contributions to your DNA are minimal (the number of ancestors doubles with each generation), and thus, that's roughly where the line is drawn.

    I look forward to hearing more thoughts on the GEDMatch calculators, though. I'm particularly curious to hear thoughts on the Eurogenes K36 mapping tool that drops you on a certain point on the map. Is that really just "fun," or is it telling us something meaningful (and does it relate to recent or distant ancestry)?
    My ethnicity estimate states "Thousands of years ago" when I click on it on Ancestry. It also says "Shows where your ancestors came from hundreds to thousands of years ago" under the overview, I think thousands of years is quite a bold claim!

    I think it's more than just "fun" these calculators and tests (in my opinion) do tell us things about our ancestral backgrounds, and how populations differ. However, at the moment these tests only test a small part of our total autosomal DNA and I suspect things will become a good lot clearer once full autosomal sequencing becomes available for ancestral DNA testing in the future. Hopefully LucaszM, Tolan, and others who work with K36 to form their tools will chime in and be able to tell us more about how that sort of thing works and what they do with it.
    Paper trail ancestry to the best of my knowledge:
    English 28.12%, East German or Eastern European 25%, Scottish 17.96%, Irish (mostly lowland Scottish origin) 12.5%, French 8.2%, Welsh 3.125%, Native American 1.95%, and Colonial American, 3.125%, which cannot be determined with complete certainty: there is Dutch (at least 1.36%) and some English. The rest could include Spanish, Norwegian, German, and French, but these percentages would be minuscule.

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