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excessive matches centromere on chrom .11

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  • excessive matches centromere on chrom .11

    Hi,
    Are there lots of matches at centromeres? I know they are usually small: 1.5-3 cM. Some persons have a segment 5-35 cM.
    I have a few other groups that congregate on the centromere of chromo. 8 or chromo. 3, but nothing like I have on chromosome 11.

    In looking at my Dad's matches, I try to sort out his father's family from his mother's family.
    I noticed that many of his mother's kin share dna on the centromere of chromo 11. Maybe 60%. I thought maybe it was from someone in the Hamaker and Harkless line.

    Then it seemed like his dad's line also had matches there, but not as many as his mother. I can't use 11 centromere data to sort out anyone now.
    Thanks,
    Sharon

  • #2
    Do you utilize Gedmatch?
    Do you have yourself (or another sibling) tested?

    At Gedmatch you can phase your fathers results with yours by setting yourself as parent and your father as child.

    This will divide your fathers DNA in half. One will be the values given to you (mixture of his paternal and maternal chromsomes), the other will be what you didn't inherit(also a mixture of his maternal and paternal chromosomes).

    For this span of his chromosome 11, one file will be his maternal and the other his paternal.

    If you also are a Tier 1 member you can then run the Matching segment search on each phased file. Each files matches that span this segment in question will be tied to his maternal line or his paternal line.

    ie)
    PF(kit#)P1 file will be say all maternal chromosome matches along that segment
    PF(kit#)M1 file will be say all paternal chromosome matches along that segment

    This may give you a better idea of which match is to which line.
    Providing your FTDNA matches also utilize Gedmatch.

    Edit
    Note though, since these files are based on what you received from your fathers random recombination of his maternal and paternal chromosomes, areas in which your DNA has the crossover between his maternal and paternal chromosomes will not yield matching segments that his complete file will.
    Last edited by prairielad; 4 December 2015, 04:16 PM.

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    • #3
      Originally posted by prairielad View Post

      ....

      Edit
      Note though, since these files are based on what you received from your fathers random recombination of his maternal and paternal chromosomes, areas in which your DNA has the crossover between his maternal and paternal chromosomes will not yield matching segments that his complete file will.
      Meaning part of fathers original segment will be in m1 file and the other part will be in P1 file, so you may match a particular match with both files in regards to segment in question.
      Beginning of segment in one file, the end in the other file.

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      • #4
        Excessive matches on centromeres

        Thanks for the Gedmatch idea.
        My dad and I are both on Gedmatch. I began the phase matching process several months ago, but only my data seemed to download.
        I'll go back and try to use it again. I read that it would help me separate my grandfather's data from my grandmother's data. With your encouragement, I will try it again.
        Regards,
        Sharon

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        • #5
          prairielad,
          I got both Dad's dna and mine to be phased. It is tokenizing now.
          I am a Tier1 member, so I'm excited to see how this all works out. It seems like time to send in another donation, Gedmatch has been very helpful to me.

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          • #6
            Just wanted to clarify in case my post was unclear.

            That the phased file you are creating for this purpose is your fathers (can do the same with mothers if tested) by entering the parent in utility as the child and the child as the parent.

            I hope it works out for you to categorize overlapping matches.
            It will at least separate out the overlapping matches to his Parent A vs Parent B providing segment you are looking at does not span a crossover point in your DNA that you inherited from him.

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            • #7
              It worked!
              This will really help with several matches.
              Also,I found 2 families who are related to my Dad's Mom and his Dad. That is not surprising, since their families followed similar immigration paths.It's amusing that the young man who has Grandma's family name only matches her for 6 cM, but matches her husband for 27 cM.

              Thank you for taking the time to explain this to me.
              Sharon

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              • #8
                Originally posted by Laizuregirl View Post
                It worked!
                This will really help with several matches.
                Also,I found 2 families who are related to my Dad's Mom and his Dad. That is not surprising, since their families followed similar immigration paths.It's amusing that the young man who has Grandma's family name only matches her for 6 cM, but matches her husband for 27 cM.

                Thank you for taking the time to explain this to me.
                Sharon
                As long as you are understanding that this is not phasing your fathers DNA into his maternal and paternal chromosomes.

                Meaning in one file, say chromosome 11, the P1 file chromosome 11 will be a mixture of his 4 Grandparents, and his M1 Chormosome 11 file will also be a mixture of his 4 Grandparents.

                You can only compare segments(not whole chromosome) that overlap on one particular chromosome to say one will be his maternal line and the other his paternal line (Parent A or Parent B).

                You can match one match with the P1 file on one section of say Chromosome 11, and also match this same match on another section of chromosome 11 in the M1 file(or another segment on another chromosome). These may very well the same Grandparent's DNA.

                See following chart depicting DNA inheritance of Grandparents' maternal and paternal chromosomes and what these reverse phasings file will be representing.

                Edit
                added onedrive link due to Attachments Pending Approval
                https://onedrive.live.com/redir?resi...nt=photo%2cpng
                Attached Files
                Last edited by prairielad; 6 December 2015, 10:52 PM.

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