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Somebody, please tell me which tests to buy!!

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  • Somebody, please tell me which tests to buy!!

    Hi all,

    I didn't realize how complicated this was and assumed the 111 test would be better than the 67 test, which in turn is better than the 37 test, but it appears I am dead wrong.

    I have three men willing to give samples for a semi-rare surname which is probably in R1b, M343 (Subclade R1b1a2, M269) to match Person 1 below.

    This is what we can prove on paper:

    Person 1 - known sample from original immigrant ancestor
    Person 2 - probable/possible match at Gen 9 (and if not, then possibly not matched at all)
    Person 3 - assumed match at Gen 10

    I understand we can't hone it down to Gen 9 or Gen 10, and I am so sad about that!! But what will a test tell us about the relationship between the three people above? Or will it tell us nothing and only Person 2 and 3 need to take the test? Or Person 1 and 2. This reminds me of one of those brain teasers and I was never any good at them!

    All we want to know is what test to suggest each person buy in order to maximize the information we get from them.

  • #2
    Originally posted by Lime View Post
    I didn't realize how complicated this was and assumed the 111 test would be better than the 67 test, which in turn is better than the 37 test, but it appears I am dead wrong.
    Why did you conclude that you were wrong?

    The more markers you test, the more refined your matches will be, so you were correct originally. 37 markers is the recommended minimum for genealogical purposes. Whether you go to the 67 or 111 marker level depends on how much refinement you want and also really depends on your goals.

    If your main goal is to confirm that these 3 men share a common patrilineal ancestor, then 37 markers should be enough for that. However, some people may recommend 67 markers to rule out coincidental matches with other closely-related families, especially if they are indeed in haplogroup R1b. It's overkill to test all 3 men for 111 markers just to find out if they share a paternal lineage.

    That said, you can always upgrade to more markers. So if you start with a lower number and decide later that you need or want more, that's not an issue. So don't stress too much over what to start with

    As you already know, the Y-DNA test won't be able to tell you precisely where on your tree each person belongs (even at the 111-marker level). There's always going to be some amount of probability as to how closely related the individuals are based on the DNA results. What won't be in question is whether they do share a paternal lineage or not.



    • #3
      37 numbers should give you a good indication that they share a common ancestor.

      Keep in mind that there will probably be some differences.

      After 3 generations I am 36/37 with a second cousin.

      You say your testing individuals are 9 and 10 generations apart.

      I assume they could possibly be 34/37 or 35/37.


      • #4
        As stated 37 markers will work. Sometimes people will order the Y37, then if they have a lot of matches in the 35/37, or 36/37 or 37/37 area they will go back and order an upgrade. Y37 will work absolutely but if you can, Y67 won't hurt and may even be needed later anyway. It all depends on your need and how much you want to spend.

        Another way to look at this is a more simple approach. Y37 will tell you if there is a connection. If that's all you want to know then Y37 works. If they are related you'll see it and if not they probably won't match, not closely anyway, not all of them indicating only 10 genersations back (which is close for YDNA).

        But as for is it a bad idea to go with Y67 or Y111? Not really. It just costs a little more and of course don't forget you'll get matches to other people in the database too. Who knows you might find a really close match you didn't know about - then you'd need the Y67 or Y111 anyway.

        I went Y67 to start with. Glad I did.
        Last edited by mkdexter; 19 July 2011, 05:42 PM.


        • #5
          Elise, Ireland and Matt,

          Thanks so much for the replies. I am 98% sure we all have a common ancestor, the only question is how far back? I will have everybody do a 67 test and go from there. Thanks for your responses.


          • #6
            Somebody, please tell me which tests to buy!!

            The FTDNATip tool can distinguish MRCA's down to the every generation level. I run that calculation whenever using every
            four generations won't tell me exactly which generation results in at least a 90% probability of having a Most Recent Common Ancestor (MRCA).

            Doing that, I was able to find that another with my surname and I share an MRCA in 1661. That calculation was the result of multiplying the number of generations ago our
            probability of a most recent common ancestor lived using the Tip
            Tool's standard of 25 years per generation = 350 years ago which is 14 generations ago, which of course is not divisible by four.