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  • Family Finder question

    How can two men match identically at 67 markers in the Y-DNA test but not be a match to each other in Family Finder? Is it because their connection is further back than the Family Finder test can predict?

  • #2
    Originally posted by Luculente View Post
    How can two men match identically at 67 markers in the Y-DNA test but not be a match to each other in Family Finder? Is it because their connection is further back than the Family Finder test can predict?
    That is a good question.I was surprised to find that one of my FF matches also matches me in most recent YSNP and we don't match at 67 markers.

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    • #3
      Originally posted by Luculente View Post
      How can two men match identically at 67 markers in the Y-DNA test but not be a match to each other in Family Finder? Is it because their connection is further back than the Family Finder test can predict?
      Yes. Remember, each generation we move back the amount of autosomal DNA we have received from the next generation back is cut in half. I match with a 4th cousin, but not his sister. When I compare the two of them they don't match in the area where I match him.

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      • #4
        Upgrade to 111 markers?

        I am the person who has a 67 0-step match and another 1-step who has no FamilyFinder connection to these individuals. Both these matches have the same surname. That surname is different from mine. My GGF said he was adopted but there is no family history of his origins other than that he was from Texas and raised his family in Arkansas. I also match with several GD steps many others with this other surname and none with my surname.

        We have a candidate for my GGF in Texas who fell off the census, etc. radar around the right time (1870 and 1880) before marrying in Arkansas (and becoming my GGF) in 1888. However, that candidate GGF is 1-step while we are finding no candidates through the 0-step match yet.

        I have two questions into which I hope someone has some insight.

        1. How likely is it that my 66/67 'relative' (in whose line we have a candidate for my GGF) is more closely related than the 67/67 'relative' with whom we haven't found any candidates for my GGF?

        2. How valuable might it be to upgrade to 111 markers for me and my 0- and 1-step matches?

        Thanks
        Last edited by ghamilton; 16 May 2014, 07:48 PM.

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        • #5
          Originally posted by ghamilton View Post
          1. How likely is it that my 66/67 'relative' (in whose line we have a candidate for my GGF) is more closely related than the 67/67 'relative' with whom we haven't found any candidates for my GGF?
          It's certainly possible. Consider a scenario where your 66/67 match acquired that mutation in just the last generation, from his father. So if his father tested, he would match you 67/67.

          Originally posted by ghamilton View Post
          2. How valuable might it be to upgrade to 111 markers for me and my 0- and 1-step matches?
          Thanks
          Not sure that this will give you a more definitive answer, but it may be worth trying to see if you have any further differences at 111 markers.

          Here's another idea:

          - Is your father still living? If so, have him take the Family Finder test, since he's one generation closer to the common ancestor.

          - Do your matches have a father (good) or grandfather (better) still living? If so, same as above -- have them take the Family Finder test.

          It's generally best to have the oldest living generation take the Family Finder test, since the autosomal DNA gets diluted by 50% every generation.

          Elise

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          • #6
            You have a less than 50% chance of matching a fourth cousin via common autosomal DNA segments.

            And each step away (i.e., 5th cousin, 6th cousin) dramatically drops even those odds.

            You probably have a 10% chance of not matching even a 3rd cousin autosomally.

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            • #7
              re: 111 yDNA @efgen @Elise

              Thank you everyone for your responses.

              As much as I can tell the three folks I refer to (me, 66/67 and 67/67) are the oldest folks living in this line.

              Do you have information on 67 vs. 111 related to the following? I'm trying to figure out if it's worth the investment for me and two others to continue with this line of testing.

              The one-step with my 66/67 is on DYS442 which is color-coded as not changing very often.

              Of my 9 'close' matches at 37, 4 are 12 STP vs my 11 STP at this location (1-4 steps at 37). The other 5 match me at 11 on that marker.

              Here are my new questions:
              1) Is the variability of similar marker randomness at the range above 67 markers (68-111) similar to those at 1-67? That is, am I really drilling down on known information or simply adding to my data pool of analysis?

              2) Similar to #1, if I get a 101/111 and a 107/111 do I need to explore the change frequency of each marker to determine the estimate of relatedness through F(ather)-F-F or does the GD relationship work the same on those markers as the 1-67 group?

              Thanks for your assistance.

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