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is X-match from mom or dad?

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  • is X-match from mom or dad?

    I'm very confused on how to read X-matches on family finder. I'm female.

    I took the lowest level MtDNA test and my haplogroup is T2b. Can it be assumed that it's most likely that any X-matches in family finder with this haplogroup is a relation through my mother's mother mother, etc?

    As far as my known ancestry going back at least a few hundred years, I'm Swedish on my dad's side through his mom. My mom was Polish and Ukrainian. My dad is passed, so there was no testing for him.

    Many of my MtDNA matches at the HRV1 level are Swedish. So, it looks like I had Swedish/Scandinavian ancestors through my mom, but probably going back past 500 years or more. Do you think? Given how close Scandinavia is to Poland, migration is very likely.

    I also have many Swedish family finder matches. But, for those Swedes that took the MtDNA test, the X-matches for many of them are the H haplogroup, along with a couple of other haplogroups. Based on this, would it be safe to say that those are relations through my dad's mom since they are NOT my haplogroup of T2b?

  • #2
    No, all it means when a family finder match's MITOCHONDRIAL haplogroup is different from your mother's is that the match is not connected through your matrilineal line. That match cannot be assumed to connect through your father's ancestry. The match could easily connect through your mother's father, or her maternal grandfather, etc. -- any line of descent where there was not a direct and continuous female to female transmission down to you.

    Do you understand that mitochondrial DNA, which follows the female line of descent, is not the same as the X chromosome?

    Everyone gets their mitochondrial DNA from their mother through cytoplasmic inheritance. Mitochondrial DNA is not a chromosome, it is a little piece of DNA that occurs within each mitochondrion, not part of the nucleus and not participating in mitosis, meiosis, recombination, etc.

    However, males get one X chromosome from their mother and a single Y chromosome from their father. Females get one X chromosome from their mother and one X chromosome from their father. This pattern of inheritance leads to some strange results, so it may be difficult to interpret matches involving the X chromosome. At least in the beginning, it is probably best to ignore X matches unless they happen to involve a predicted close relative (predicted second cousin or closer at least).

    The best way to distinguish maternal from paternal family finder matches is to test one or more fairly close known relatives (a parent, if that is possible), preferably from each side of the family.


    • #3
      Originally posted by John McCoy View Post

      Do you understand that mitochondrial DNA, which follows the female line of descent, is not the same as the X chromosome?
      See? Told you I was confused. That actually did occur to me after I wrote.

      Thanks for clarifying. It makes more sense now. I think it's best to not pay too much attention to X-matches for now at least.


      • #4
        One thing nobody ever seems to mention is the fact that part of the X chromosome recombines with the Y Chromosome.

        So it is in fact possible for you to inherit part of your X chromosome from your mother's father's father. Your mother's father's X partially recombined with his Y, so one of your mother's X's contains a portion of her father's Y, and then her two X's recombine and you likely get some of that passed onto you.

        The same holds true for your father. Part of his X and Y recombined, so if you are male, you received part of the X he got from his mother in your Y chromosome, and of course the rest of the Y from him, but even his Y was a combination of his father's X and Y. If you are female, you still receive part of the Y that your father got from his father.

        Moral of the story is, the X match doesn't filter out the part of the X that recombines with the Y, so it is not a very accurate indicator of anything.

        Oh, and here's a video that shows how the X/Y recombination is different than the other chromosomes!