You know, this is the BEST explanation of these tests that I have ever seen. Thank you very much for taking the time to explain. I think I will go back and have another look at my father's test now. Connie On Sun, Jun 9, 2013 at 10:18 AM, Bill Davidson <[log in to unmask]> wrote: > The Y chromosome test (that only men can take) has certainly been the > "gold standard" over the years. That test is "representative" of the male > donor's father, his father's father, his father's father's father, etc. > etc. So....if the male DNA donor is a Mr. Jones, for example, then the Y > chromosome DNA test result would typically be "representative" of his > entire "Jones line." The "monkey wrench" that can be thrown into this test > (and into any other DNA test), however, is if there was a "non-paternity > event" (i.e., an adoption or an out-of-wedlock birth), somewhere in the > donor's line. For example, my mother (who was born a Miss Brown) had a male > cousin who is a Mr. Brown, but his Y chromosome DNA test results were a > match to only three men who are all Mr. Smiths. We now know that my > maternal gg-grandfather named Smith W. Brown was actually an "Smith infant" > who was taken-in, named and reared by a Brown family in Middlesex Co., VA > (hence, my mother was actually a "biological Smith" versus a "biological > Brown"....though she went to her grave in 1997 without knowing that). > > The mtDNA test (which can be taken by a man or a women) is > "representative" of the donor's mother, that mother's mother. that mother's > mother's mother, etc. etc. While similar in concept to the Y chromosome > test, the results from this test present a much harder challenge to > research. That is because every time a woman marries, she receives a > different last name. For example, my mother was a Miss Brown/Mrs. Davidson, > but her mother was a Miss Roudabush/Mrs. Brown, while the mother of this > last woman was a Miss Messick/Mrs. Roudabush. So....it can become quite > complicated to "use" the results of this test (plus, a lot of people have > no idea what the maiden name of their mother's mother's mother's mother > was, for example). > > The third popular DNA test is called the "Family Finder" test by Family > Tree DNA, and other companies like "Ancestry" and "23andme" have a similar > test. This test can be taken by a man or a woman, and it will basically > show "DNA matches" to people (who have also taken this same test) who share > any common MALE or FEMALE ancestor with the donor within the last four or > five generations (this test apparently can provide some "false > positives"....and/or omit relatives all together....once you go back more > than about four or five generations). People who take this test frequently > have hundreds of matches, since all kinds of male and female cousins can > "appear" (with a variety of last names). So....this test can be even harder > to "interpret" than the mtDNA test....but is has still proven to be very > valuable to some researchers. As an example of the difficulty, one of the > donor's "matching" relatives (who also took this DNA test) could be a Mrs. > Jones/Miss Smith, for example, but the REASON that the donor is a match to > that Mrs. Jones/Miss Smith could be because both donors share a "common > Brown relative" from a few earlier generations....plus that "common Brown > relative" could have been on either donor's father's "side of the family" > or on the mother's "side of the family"....so you can image the effort it > can take to "make sense" of the results from this test. > > I took the 37 marker Y chromosome test at Family Tree DNA, and I have six > other men named "Davidson" at this time who are an "excellent DNA match" to > me....and I now know how every one of them connects to my "Davidson line" > (and I have similar DNA test results for the above-mentioned Smith/Brown > family). I have "traced" all three of these surnames (Davidson, Brown and > Smith) to men in those families who were in Virginia in the 1600s. > > Comments/questions? > > Bill > > To subscribe, change options, or unsubscribe, please see the instructions > at > http://listlva.lib.va.us/archives/va-roots.html > To subscribe, change options, or unsubscribe, please see the instructions at http://listlva.lib.va.us/archives/va-roots.html