No announcement yet.

DNA Test For Maternal Grandfather's Line

  • Filter
  • Time
  • Show
Clear All
new posts

  • DNA Test For Maternal Grandfather's Line

    I had my Y-DNA and mtDNA tests done in 2012. At the time, I really didn’t understand what the mtDNA test showed other than it was my mother’s line. After the test was done, I realized that it is only showing my mother’s mother, my grandmother’s mother, my great grandmother’s mother, etc. I was pretty disappointed as I was hoping the test would have my mom’s father’s line. My main purpose was to hopefully one day find out who my grandfather’s mother’s unknown father was. It was never talked about in the family and DNA seems to be the only other way of hopefully connecting someone else from this bloodline.

    Is there a DNA test that would give me results for my mother’s father’s line? And his mother’s father? The exact line I want to test would be my mom, her father (my grandfather), his mother (my great grandmother), and then his mother’s father (my great great grandfather), etc.

    Would I need to get my mother to do a DNA test for that? Or do I need to get one of her two living brothers to do the test? If my mom or one of her brothers do need to do a test, would it need to be the Y-DNA to do this?

    I sure would appreciate any information that would help me purchase the correct DNA test. I have read everywhere and I'm just not sure what I should do.

    Thanks a lot.

  • #2
    If your grandmother had a full brother you could do a Y-DNA tests on her full brother or one of his sons. Y-DNA is passed from father to son. Your mother's brothers have their father's DNA, not their maternal grandfather's.

    Your best bet is to do a Family Finder test on your mother and as many of her siblings as possible. If your grandmother is still living test her instead, but I assume she is not.

    With Family Finder, you get cousins in all lines and you really have to work to try to find out which match belongs to which line. If your lucky, you'll get some close matches in the line you are interested in.


    • #3
      Thanks so much for the info. I really appreciate it.

      My great grandmother only had one half-brother and he had a different father (who is unknown as well). I will hopefully get my mother to do the Family Finder test. I'm not sure if I can get her two brothers to do a test.

      Would the Family Finder test work if I took the test? Or should I have my mother take the test? I remember reading back in 2011 when I was getting ready to do the Y-DNA and mtDNA tests that they weren't able to get complete results on females yet. Thanks again.
      Last edited by mwb1234; 31 January 2018, 11:12 AM.


      • #4
        It will work fine if you do the test, But your mother has 50% of her mother's DNA and you only have 25%. You have a chance of finding close cousin's with your DNA, but a better chance with your mother.

        Each sibling gets a random 50% of each parent's DNA. Only identical twins have identical DNA. Other siblings share around 50% of DNA with each other. If you test several siblings, you manage to cover a large amount, if not all, of the DNA of the deceased parent. That may or may not be important. You may strike it lucky right away.

        If a person can test both of their parent's they don't need to test themselves, since they got all their DNA from their parents.

        It would also be good to test your mother, or yourself, if you can't test her, at They have the worst tools and an inferior DNA test, but sometimes the enormous size of their database can really help with finding very close relatives. Even if you find close relatives, they probably won't have trees or answer messages and you have to be a real Sherlock Holmes to try to find out who they are.


        • #5
          This information is great. Thanks so much. I wish I had thought to post in the forum a long time ago. Also, thanks a lot for the info about Ancestry. I had been wondering how the DNA test at Ancestry compared with Family Tree DNA. I think my plan will be to go ahead and test my mother with Family Tree DNA for now and see if I get lucky with the results. I just might do the Ancestry test later on too just to cover even more ground.

          Thanks so much, this makes so much sense to me now.