GEDmatch HELP

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  • wvcountrygirl01
    FTDNA Customer
    • Jul 2018
    • 1

    GEDmatch HELP

    I'm new at this DNA and after researching everything, I'm more confused then ever. I'm trying to find information on my great-grandfather. From the stories I've received he had changed his name and had multiple wives and children. I cant find any information on the name change since this was in the 1920s and I'm unsure if I have the correct man or am I'm following the wrong family history. I found a guy on Ancestry that has the same name as my great-grandfathers original name listed in their family tree. I did the GEDmatch since they had done their DNA on Ancestry and mine was done on 23andme. If my information is correct then my 4th great grandfather and his 3rd great grandfather would have been the same person. To make it easier to explain.. Leonard is supposedly my 4th great grandfather, his son William was this guys great-great grandfather. Leonard also had another son name AM. AM would have been my 3rd-great grandfather.

    The guy from ancestry's grandmother (mothers mom) was the decedent of Leonard. When doing the GEDmatch one on one comparison with the ancestry guy - it showed 0 DNA shared segments but when I compared his mother's DNA it showed came back with this...

    Largest segment = 7.2cM

    Total Half-Match segments (HIR) = 7.2cM (0.200 Pct)
    Estimated number of generations to MRCA = 7.5

    1 shared segments found for this comparison

    155608 SNPs used for this comparison
    52.073 Pct SNPs are full identical
    **************************************
    Chr section:

    Chr 15
    B37 Start Pos'n - 98,924,124
    B37 En Pos'n - 101,802,565
    cM - 7.2
    SNPs - 263
    **************************************

    After reading several articles I'm confused to know if I'm really related the guy and his mother or did his mother and I just match on chance? Why wouldnt the guy show any shared DNA if his mother did, would it be because hes further down the line? If someone could explain this in simple terms that would be great.
  • travers
    FTDNA Customer
    • Oct 2010
    • 553

    #2
    Originally posted by wvcountrygirl01 View Post
    After reading several articles I'm confused to know if I'm really related the guy and his mother or did his mother and I just match on chance?
    That's a good question, but yes you share DNA so you are related but if it is through the ancestor you think it is or through another ancestor it would be difficult to determine at this point. You say this person is a descendant of William and you are a descendant of AM, you say they are sons of Leonard so assuming William and AM had the same mother as well you would be 4th cousins once removed to the man you found on Ancestry and you are a 3rd cousin twice removed to his mother. On an autosomal DNA test you will only have about a 50% chance of matching a 4th cousin and the odds go down the further related you are to somebody beyond that.
    Being 3rd cousins twice removed is the genetic equivalent of being 4th cousins so if your theory is correct you only had a 50% chance of DNA matching the mother and a smaller % chance of matching her son (I don't know the exact figure but lets say 30% because 5th cousins have about a 10% chance of matching and 4th cousins once removed would be in between a 4th and 5th cousin relationship). The closer the relationship the more likely you will share DNA and the greater the amount shared. As you see you share some DNA with his mother but it is very little so it would be difficult to say where that DNA came from and is just not enough data to say anything for certain. So while the DNA result between you and their family doesn't confirm your theory it doesn't disprove it either as 4th cousins if they match at all will most of the time share very little DNA.

    Originally posted by wvcountrygirl01 View Post
    Why wouldnt the guy show any shared DNA if his mother did, would it be because hes further down the line? If someone could explain this in simple terms that would be great.
    Yes. A child receives only 50% of each parents DNA so 50% of each parents DNA you don't have. As mentioned the further related the less odds of matching because of this. This is a pretty good explanation of how autosomal DNA is inherited if you go to this link and play the "Autosomal DNA" clip https://learn.genetics.utah.edu/content/basics/molgen/. This is why it is best to test your parents and grandparents (or aunts, uncles) if they are still living and so it would be recommended to test the closest related living relative of this great grandfather that you can. I would also recommend continuing to do research as you might come across something that gives you your answer on why your great grandfather changed his name and whether or not you have located the correct family he belongs to. You might also want to consider testing at Ancestry and/or here at FTDNA as only a small percentage of their testers upload to Gedmatch and again if you have older relatives from the line in question it would be best to test them before testing yourself if money is an issue. With more research and with more DNA matches to that family you will have a greater confidence in whether your theory is correct or not.

    Comment

    • John McCoy
      FTDNA Customer
      • Nov 2013
      • 1023

      #3
      The relationship you stated, your 4th great-grandfather (that means great-great-great-great grandfather -- is that what you meant?) is the other guy's 3rd great-grandfather, would make you 3rd cousins once removed. While you could end up with just 7 cM shared with a person that distantly related to you, 7 cM does NOT prove that the relationship is that close. It could easily be many generations back. Consequently, you haven't proved or disproved the idea that you are related to this person at the degree you indicated.

      Are there any other CLOSE relatives (cousins, aunts, uncles, for example) who have been tested? You would be on a much more solid footing to look for stronger matches that you share with a close relative. At least to start with, you should be paying attention to your strongest matches FIRST, and rarely pay any attention at all to matches where the shared cM is less than about 10, because these are likely to be much too far back to identify with any certainty, even if you happened to have a very deep and very complete pedigree.

      You mention the period around 1920. At that date, you should be able to find many records -- unless your ancestor was taking pains to remain hidden! -- such as census, newspaper articles, deeds, voter registration rolls, etc. One of the first principles of genealogy is to start from the present, and DOCUMENT each generation thoroughly before moving on to the preceding generation. 1920 is recent enough you should be able to find the "paper trail" and follow it!

      If you haven't already done so, you should investigate whether there is a genealogy society in your area whose meetings you can attend. Genealogy societies are full of people who started out just like you, and their members have centuries of collective experience in tracking down elusive ancestors. They will be happy to listen to your story and offer suggestions. Good luck!

      Comment

      • travers
        FTDNA Customer
        • Oct 2010
        • 553

        #4
        Originally posted by John McCoy View Post
        The relationship you stated, your 4th great-grandfather (that means great-great-great-great grandfather -- is that what you meant?) is the other guy's 3rd great-grandfather, would make you 3rd cousins once removed.
        That would be 4th cousins once removed, agree with everything else written.

        wvcountrygirl01 you might know cousin relationships better than me but I use an online cousin calculator here: http://www.searchforancestors.com/ut...alculator.html or there are charts online if you prefer a more visual way of determining. Also a good research tool is the DNA Painter Shared cM Project tool it will show you a lot of the possible relationships based on the amount of DNA shared. If you plug in the amount you share in this case you will see there are many, many possible relationships and that doesn't even account for if you are related or not on the family line you believe you are related on. https://dnapainter.com/tools/sharedcmv4

        But yes, this is definitely something you can eventually prove through DNA with more matches or closer matches but it might also be able to be proved through traditional genealogy so good luck on both fronts. A couple years ago I DNA matched a woman who had begun researching her father's history after his death and couldn't find anything about his childhood. He never talked about his early life when alive and had married and children late in life so even his wife didn't know his beginnings. In her research she found a birth record with the same birthdate and first and middle name as her father but a different last name. It turns out that man had deserted while training in World War I and was never seen again, assumed dead. The daughter took a DNA test and was able to confirm that man was her father. I am only a 4th cousin to her but she has many close matches to the grandchildren of her father's siblings (who are the same age as her even though they are from different generations due to her father being in his 60's when she was born).

        Comment

        • John McCoy
          FTDNA Customer
          • Nov 2013
          • 1023

          #5
          You're right, I missed a "G" when I sketched out the tree!

          I have trouble believing that a 4g-grandfather was alive in 1920, as mine, whoever he was, was already dead by 1840. I'm guessing there's more to this problem that needs to be sorted out.

          Comment

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