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  • Both parents tested

    My wife's parents both did family finder tests, and we are managing the kits. She hasn't yet done a test. Is there anything to gain by her testing as well? Thanks.

  • #2
    If both of her parents tested, your wife doesn't need to test. She received 50% of her DNA from each parent. She might get a few very distant matches that her parents didn't get, but they wouldn't be helpful.

    If you want to do more testing, it would be better to test her grandparents, if any of them are living, or her aunts and uncles.

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    • #3
      Originally posted by MoberlyDrake View Post
      If both of her parents tested, your wife doesn't need to test. She received 50% of her DNA from each parent. She might get a few very distant matches that her parents didn't get, but they wouldn't be helpful.

      If you want to do more testing, it would be better to test her grandparents, if any of them are living, or her aunts and uncles.
      I agree, if willing to do more testing, concentrate on the older generations first as each parent only received 50% of their parents DNA. If their siblings(wifes Aunts and Uncles , or wife's cousins) are available for testing they will be carrying some of the 50% that your wife's parents did not inherit.

      It will potentially broaden your match base.
      Last edited by prairielad; 26 October 2016, 05:09 PM.

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      • #4
        Originally posted by MoberlyDrake View Post
        If both of her parents tested, your wife doesn't need to test. She received 50% of her DNA from each parent. She might get a few very distant matches that her parents didn't get, but they wouldn't be helpful.
        In the cases known to me, the extra matches are plain misleading. For example, one third of matches a child has are not common to either parent. Their Shared centiMorgans could be quite high, but usually their Longest Block would be low.

        Originally posted by MoberlyDrake View Post
        If you want to do more testing, it would be better to test her grandparents, if any of them are living, or her aunts and uncles.
        Exactly. Essentially go wide, then you might find some gems.

        Mr W

        P.S.
        I am trying to not test children, but sometimes after children are tested, their parents would agree to testing they were hesitant to do before.

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        • #5
          Originally posted by dna View Post
          In the cases known to me, the extra matches are plain misleading. For example, one third of matches a child has are not common to either parent. Their Shared centiMorgans could be quite high, but usually their Longest Block would be low.
          I'll take a contrarian viewpoint. I think most parents are going to have a common ancestor say within the last ten generations. I have found that the small segments which the child has, but the parents don't, are actually reconstructions of a segments of that common ancestor's DNA and they will match with another person's DNA. Someone postulated that DNA from the parents creates a false segment termed a pseudo-segment. That idea is completely baseless and it is easily shown to be false.

          Of course, I would test a grandparent first, but I would still want a test for the child.

          Jack Wyatt
          Last edited by georgian1950; 28 October 2016, 02:20 AM. Reason: clarity

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          • #6
            Originally posted by georgian1950 View Post
            I'll take a contrarian viewpoint. I think most parents are going to have a common ancestor say within the last ten generations. I have found that the small segments which the child has, but the parents don't, are actually reconstructions of a segments of that common ancestor's DNA and they will match with another person's DNA. Someone postulated that DNA from the parents creates a false segment termed a pseudo-segment. That idea is completely baseless and it is easily shown to be false.

            Of course, I would test a grandparent first, but I would still want a test for the child.

            Jack Wyatt
            Yes, I disagree with the above.

            Please see http://isogg.org/wiki/Identical_by_state in particular the references given there for a discussion related to the pseudo segments.

            Mr W

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            • #7
              Originally posted by dna View Post
              Yes, I disagree with the above.

              Please see http://isogg.org/wiki/Identical_by_state in particular the references given there for a discussion related to the pseudo segments.

              Mr W
              Consider this.

              My mother in a 'one-to-one' comparison with a person whose four grandparents are from Nigeria, using the ultra low parameters of 250 SNP's and 1.0 cM minimum segment has only one small matching segment. It's is probably a good one because she has a distant mulatto ancestor from Barbados and a person with known African heritage triangulates on that segment. Conventional methodology would say parameters that low would cause all kinds of small false-positive segments. Both kits are 23andMe V4 chipset, so incompatiblity is not the answer. Some of you might be aware of the source of common ancestry about 300 years ago for many of us which I found the source of.

              The point is, if two just slightly related kits will not produce false segments, a case where two parents share DNA from a common ancestor can only produce matching segments which corresponds to the DNA of the ancestor.

              Jack Wyatt

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