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Y dna question

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  • Y dna question

    I have a cousin looking for his bio father. So far searching the family tree has not helped make any connections. Ancestry dna has only provided cousin matches. Would having him do the Y dna provide a Surname to help us in this search?

  • #2
    Y DNA test can sometimes point you very strongly to a particular surname. Not always by any means, in part because Y chromosomes are usually more stable than surnames were in historical times! That is, closely related men from several centuries ago, who shared identical Y chromosomes, might have chosen different family names when it became fashionable to have a permanent surname. Some modern surnames can be traced back through the paternal line as early as the 13th Century or maybe even earlier, others were not chosen until the 19th Century, and surnames have been changed along the way for any number of reasons. Sometimes a Y DNA test will put you in a group where ALL the close matches have the same surname, at other times the close matches will have many different surnames. Because of the possibility that the results will provide a useful clue, it's worth doing, but it's probably best to go direct for the Y-67 test if that's possible, on the theory that any close matches you get are likely to be reliable.


    • #3
      So the person can be tested alone and will get some type of results indicative of possible surnames?


      • #4
        What you get from the Y-STR tests, such as Y-67, is a list of matches (with surnames) with their "genetic distance" (roughly, the number of differences between your kit and theirs) from your kit. Very close matches -- with 1 or 0 differences -- are what you hope to find. If all the close matches, or the vast majority, happen to have the same surname, that's definitely a clue!


        • #5
          y matches

          could help, my closest 3 matches on the Y67 test have the same surname as myself...although 12 of my 24 matches share a surname which is different from my surname.

          if you do the Y test you should do the 67 marker test. too many of the matches at 37 markers may not be matches at 67 markers and some of my 67 marker matches do not appear as matches at 37 markers.


          • #6
            Just be aware that it's a game of chance, totally dependent on who else has decided to test. If nobody else on your cousin's biofather's direct line has tested then he won't have any matches. My only matches are two known cousins (ignoring Y25, where I do have other matches but where many of the matches are definitely IBS false matches (wrong haplogroup) or probably false).

            I still think it's worth doing. Your cousin could get lucky and find strong matches straight away. Even if he doesn't, once he has his results he can ask other people to take the test if he has reasons to suspect that they're on the patrilineal line.

            I agree with jova99 and John McCoy: you should go straight for Y67. With a close match at Y37 you will know that there's a link, but you won't have any accurate way of knowing how many generations or even centuries ago the common ancestor lived. A distant relationship increases the chances that the surname has changed for whatever reason. With a close Y67 match you can be much more confident that the common ancestor lived relatively recently.


            • #7
              It's definitely worth a shot. So yes you should have your brother take the Y-DNA test, and take advantage of the DNA day sale currently going on and get a big discount.