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Matching and overlapping Segments w the chromosome browser?

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  • Matching and overlapping Segments w the chromosome browser?

    I am hoping someone here can answer my question regarding the chromosome browser.

    I go to chromosome browser for the kit of James. I enter 3 match names from James' match list. 2 of the names are related to James thru his father. The 3rd name is related through his mother. All 3 match nearly identical on a segment more than once, some other segments are overlapping of the 3.

    I know 1 & 2 are closely related. 3 is not related to 1 & 2.

    1 & 2 are, of course, not on 3's match list and vice versa.

    Is this correct? Just because the segments of the 3 match does not mean there is a common ancestor for matches 1 & 2 with 3? IF they do not appear on each others' match list that pretty much answers the question?

    I think I am confusing myself .......... I just need clarification because I am chasing my tail.

  • #2
    Most likely Match#1 and Match#2 are not related to one another, although you are related to both of them through separate lines.

    I suspect the problem is that the chromosome broswer just isn't that user-friendly. Sounds perfectly normal to me, and that you have the situation under control.

    Every genetically normal human being has two copies of each chromosome--although the Chromosome Browser utility maps only one set.

    FTDNA probably did this in the interest of maximizing computational efficiencies for the matching process, but it can give you the misleading impression that some of your maternal matches share DNA with your paternal matches. You really have to use the "In Common" filter as well as the chromosome browser to get a real handle on where the segments lie.

    Mind you, that could really be the case--it's a smaller world than you'd imagine. But more likely, if you investigate Match#1 and Match#2 with the "In Common" filter, you will find that they are not matches to one another, meaning that you are merely viewing the computational artefact I described above.

    This is one of my main beefs with FTDNA's chromosome browser configuration. I understand that they can't be chewing up endless gobs of computational power on this sort of thing, but at least they could allow you to directly compare your matches to one another (rather than only through your own results). Gedmatch does a great job of this.

    Ever
    Originally posted by TMontes View Post
    I am hoping someone here can answer my question regarding the chromosome browser.

    I go to chromosome browser for the kit of James. I enter 3 match names from James' match list. 2 of the names are related to James thru his father. The 3rd name is related through his mother. All 3 match nearly identical on a segment more than once, some other segments are overlapping of the 3.

    I know 1 & 2 are closely related. 3 is not related to 1 & 2.

    1 & 2 are, of course, not on 3's match list and vice versa.

    Is this correct? Just because the segments of the 3 match does not mean there is a common ancestor for matches 1 & 2 with 3? IF they do not appear on each others' match list that pretty much answers the question?

    I think I am confusing myself .......... I just need clarification because I am chasing my tail.

    Comment


    • #3
      Thank you for your response. 1 is a cousin to James, 2 is a 2nd cousin to James-BOTH share James' grandparents in the pedigree (through James' paternal side). 3 is cousin to James through the maternal side. 3 appears only as a match on James' list.

      NOW that said, #3 does have a few distant matches of names found on the others' match list---far far away matches.

      I guess what I am trying to get my head wrapped around is the idea that it would be advantageous to see a listed match's match list to sift through just what distant lines connect.

      Comment


      • #4
        Originally posted by TMontes View Post
        I guess what I am trying to get my head wrapped around is the idea that it would be advantageous to see a listed match's match list to sift through just what distant lines connect.
        If #1 and #2 are matches "In Common" and #3 is NOT "In Common" to #1 or #2, then you are most likely correct that #1&#2 are paternal and #3 is maternal.

        That's all.

        Comment


        • #5
          When GEDMATCH comes back for use I will download the latest results. I have downloaded 4 tests but when this last bunch came back, the website put a temp hold on accepting downloads.

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