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My Origins & relationship to matches

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  • My Origins & relationship to matches

    The following question may have you rolling in the aisles with laughter but I am a novice at DNA and have found what seems logical to me isn't necessarily so in the DNA world hence the following question.

    I have undertaken the Family Finder test and in part expected to see some Danish ancestry as my great great grandfather was Danish. However My Origins did not reveal any Danish nor any Scandinavian.

    Does this mean that none of my matches will also not be Danish or Scandinavian?

  • #2
    Originally posted by Martha View Post
    my great great grandfather was Danish. However My Origins did not reveal any Danish nor any Scandinavian.

    Does this mean that none of my matches will also not be Danish or Scandinavian?
    You should have some Danish matches despite MyOrigins's oversight. Check your Family Finder match list (not only your MyOrigins screen's match list) carefully after your kit is fully processed, then let us know what kinds of northerly matches you find.

    In the opposite scenario, MyOrigins thinks my father is 7% Scandinavian but he has no non-Jewish all-Scandinavian matches, neither in Family Finder nor in Gedmatch, and our family lived far from Scandinavia and has no tradition of Scandinavian heritage. This came about because he has a little bit of Polish admixture from way back and the calculator sometimes has problems distinguishing between North European ancestries. I inherited 3 of those Polish segments (ones I'm able to triangulate with Poles at Gedmatch and determined are South Baltic in origin) from my father and while MyOrigins claims I'm also 7% Scandinavian, DNA.LAND gives me only 0.47% other (that is, other than 99.53% combined Ashkenazi Jewish + Sephardi Jewish), and when I manually added up those 3 Polish segments by cM lengths and divided by my total autosome I got 0.48%.
    Last edited by khazaria; 20 October 2015, 05:25 AM.

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    • #3
      My estimated Polish percentage I gave in my message is slightly off. Gedmatch actually has an autosomal total of 7174 cM compared to FTDNA's 6766.2 and 23andMe's 7074.6.

      32.8 cM Gedmatch segments / 7174 cM Gedmatch total = rounds up to 0.46%.

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      • #4
        In my experience, the MyOrigins results shouldn't be taken seriously unless they give a strong signal. The algorithm doesn't seem to be able to distinguish very well between populations that are close together on the map. There are at least a couple difficulties to consider.

        First, there doesn't seem to be a way to verify that whatever genetic markers any of the "admixture tools" associate with a given population are really good predictors of ethnic origins. In fact, I have to wonder if good predictors can ever be found, given the amount of migration and mixing that has occurred in historical times in Europe and elsewhere.

        Second, there is a significant probability that you won't have any DNA at all from some of your ancestors. It's not unusual for, say, 4th cousins to share no significant segments. This happens because of the way recombination works. There is just enough recombination at each generation to pass on a few dozen chunks of DNA (organized into the 22 autosomes). It is not the case that DNA is completely scrambled at each generation. You are likely to end up with large chunks from some distant ancestors and nothing at all from others. This effect will inevitably skew the "ethnic origins" figures in some way.

        One indication of the difficulty of predicting ethnic origins is the number of different tools that have been developed, and the different results that they produce. You can find a baffling array of "admixture tools" on GEDmatch.com. Is any of them better than the others? I don't know how that question can be answered!

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        • #5
          Originally posted by John McCoy View Post
          You can find a baffling array of "admixture tools" on GEDmatch.com. Is any of them better than the others? I don't know how that question can be answered!
          Many of the Gedmatch tools overstate the extent of my Polish ancestry, often suggesting I'm between 5 and 7 percent Polish, which doesn't match up with reality. However, they are useful in detecting elements that exist. Eurogenes's suite of tools is the most consistently useful for me and my matches.

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          • #6
            Danish Origins and resulting matches

            Originally posted by khazaria View Post
            You should have some Danish matches despite MyOrigins's oversight. Check your Family Finder match list (not only your MyOrigins screen's match list) carefully after your kit is fully processed, then let us know what kinds of northerly matches you find.

            In the opposite scenario, MyOrigins thinks my father is 7% Scandinavian but he has no non-Jewish all-Scandinavian matches, neither in Family Finder nor in Gedmatch, and our family lived far from Scandinavia and has no tradition of Scandinavian heritage. This came about because he has a little bit of Polish admixture from way back and the calculator sometimes has problems distinguishing between North European ancestries. I inherited 3 of those Polish segments (ones I'm able to triangulate with Poles at Gedmatch and determined are South Baltic in origin) from my father and while MyOrigins claims I'm also 7% Scandinavian, DNA.LAND gives me only 0.47% other (that is, other than 99.53% combined Ashkenazi Jewish + Sephardi Jewish), and when I manually added up those 3 Polish segments by cM lengths and divided by my total autosome I got 0.48%.
            Many thanks for your reply. I don't understand how I determine 'my northerly matches'

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            • #7
              Originally posted by Martha View Post
              I don't understand how I determine 'my northerly matches'
              One way is to go to the Family Finder screen and look at any users who have listed their surnames and ancestral locations. There's an ancestral surname search form that lets you narrow the list down to those who list ancestors from "Denmark" (yes, you can enter a country or town in that search field).

              You can also download the complete match list and browse through it if you have the software program Microsoft Excel or an equivalent that handles .csv format files. The file you want to download will be named ######_Family_Finder_Matches_201510DD.csv where ###### is your kit number and DD is the day of the month.

              Also, some of the customers place information pertaining to their direct paternal and direct maternal lines in their personal info box that pops up when their name is clicked. So there may be Danish surnames and towns in some of those too.

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              • #8
                Originally posted by khazaria View Post
                One way is to go to the Family Finder screen and look at any users who have listed their surnames and ancestral locations. There's an ancestral surname search form that lets you narrow the list down to those who list ancestors from "Denmark" (yes, you can enter a country or town in that search field).

                You can also download the complete match list and browse through it if you have the software program Microsoft Excel or an equivalent that handles .csv format files. The file you want to download will be named ######_Family_Finder_Matches_201510DD.csv where ###### is your kit number and DD is the day of the month.

                Also, some of the customers place information pertaining to their direct paternal and direct maternal lines in their personal info box that pops up when their name is clicked. So there may be Danish surnames and towns in some of those too.
                Thanks so much for the clarification.

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