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Recombining DNA after subsequent generations

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  • Recombining DNA after subsequent generations

    OK so I'm using DNA Painter and I'm using my autosomal results and my father's. He has DNA matches I don't have that are confirmed in areas that on my DNA profile are blank. I want to paint in that area using matches from me who also match in that spot, even though they aren't linked to that specific ancestor who is confirmed on my dad. I'm hesitating though because I don't know if when my dad passes down his chromosomes, his DNA recombines in the exact same spot as me. Can someone explain more? Thanks!

  • #2
    Here is a chart of my families chromosome 2.
    It shows how my Grandparents maternal and paternal chromosomes recombined to form my fathers maternal and paternal chromosomes
    It then shows how the random recombination of my fathers maternal and paternal chromosomes formedunique paternal chromosomes in myself and 5 of my siblings.

    It may give you a visual understanding of recombination of a parents maternal and paternal chromosomes as they are passed on to child.

    Recombination is the formation of a single chromosomes from two by zig zagging back and forth between parents pair, taking one section from one then switching to the other for next section
    Attached Files

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    • #3
      Let's see if I can follow what you are trying to do. Are you trying to use DNA Painter on your own kit? In that case, any segments you have that don't match your father must have come from your mother.

      Or are you trying to use DNA Painter on your father's kit? As I understand it, the purpose of DNA Painter is to "color in" segments whose ancestry has been identified in some way. For that purpose, the segments that you received from your father are not relevant, because you are his "descendant", and not one of his "ancestors". Likewise, kits that match your own kit, but don't match your father, can't be used to "paint" his DNA.

      Does that help, or are you trying to ask a different question?

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      • #4
        Originally posted by John McCoy View Post
        Let's see if I can follow what you are trying to do. Are you trying to use DNA Painter on your own kit? In that case, any segments you have that don't match your father must have come from your mother.

        Or are you trying to use DNA Painter on your father's kit? As I understand it, the purpose of DNA Painter is to "color in" segments whose ancestry has been identified in some way. For that purpose, the segments that you received from your father are not relevant, because you are his "descendant", and not one of his "ancestors". Likewise, kits that match your own kit, but don't match your father, can't be used to "paint" his DNA.

        Does that help, or are you trying to ask a different question?

        John, I was trying to see if I can apply the same areas my dad matches with someone to my own profile to fill in blank areas. The more I thought about it though, I don't think that's a good idea, unless there is a proven phased match. If we laid out two sides, my mother's chromosomes and my father's, his contribution is going to theoretically contain 50 percent of his dad's and 50 percent of his mom's. So to me, I would only share really 25 percent of his parents, squeezed into his chromosome side. Some ancestors that would appear on his DNA painter profile, wouldn't be on mine at all, squeezed out by dilution.

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        • #5
          Because of recombination and the random assortment of chromosomes, your mother does not automatically pass on 50 percent of her mother's (your maternal grandmother's) autosomal DNA. At each meiosis, human autosomal DNA is passed on in the form of about 3 dozen "chunks" formed into 22 chromosomes. It is definitely feasible that your mother passed on, say, 40 percent of the DNA she got from her mother, in which case the other 60 percent of what she passed on to you would have to be DNA she got from her father. When this process is repeated in successive generations, the result is that we may have no autosomal DNA at all from some ancestors, and correspondingly more from others. Just one more complication that will affect how your painted chromosomes turn out!

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