Announcement

Collapse
No announcement yet.

How many possible values for 12-marker Y-test?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • How many possible values for 12-marker Y-test?

    Beginner's question: I had a 12-marker Y-chromosome test at FTDNA. I expected to have lots of exact matches, and then upgrade my test to eliminate them. I was surprised to learn I had no exact matches at all.

    This seems to lead to a natural question: how many different possible values are there, for the 12-marker test? (And how many of the possible ones are represented in the FTDNA or ySearch data?)

    Mike Carroll

  • #2
    Originally posted by Mike Carroll
    This seems to lead to a natural question: how many different possible values are there, for the 12-marker test? (And how many of the possible ones are represented in the FTDNA or ySearch data?)
    There are more than 3 billion possible different 12 marker haplotypes. Possibly many, many more.

    There are 21,916 different 12 marker haplotypes in FTDNA's database, and probably less than that in ySearch.

    Comment


    • #3
      Originally posted by Mike Carroll
      Beginner's question: I had a 12-marker Y-chromosome test at FTDNA. I expected to have lots of exact matches, and then upgrade my test to eliminate them. I was surprised to learn I had no exact matches at all.
      It is not unknown for an 11/12 near-match to grow into a 24/25, and even 36/37, match. IMHO, a lack of exact matches is not a reason not to upgrade.

      Besides, even loose near-matches such as 32/37 may be able to tell you about your ancestry, even if it is out of the range of conventional genealogy.

      Comment


      • #4
        Originally posted by lgmayka
        It is not unknown for an 11/12 near-match to grow into a 24/25, and even 36/37, match. IMHO, a lack of exact matches is not a reason not to upgrade.

        Besides, even loose near-matches such as 32/37 may be able to tell you about your ancestry, even if it is out of the range of conventional genealogy.
        One of my 10/12 matches became 23/25 match and my only exact match became 22/25 when I upgraded to 25 markers.
        Last edited by Eki; 15 January 2007, 11:38 PM.

        Comment


        • #5
          How many possible values for 12-marker Y-test?

          Originally posted by vineviz
          There are more than 3 billion possible different 12 marker haplotypes. Possibly many, many more.

          There are 21,916 different 12 marker haplotypes in FTDNA's database, and probably less than that in ySearch.
          3 billion at least. Wow. So 1% of that is, what, 30 million, making 25,000 or so a tiny fraction of 1%. I guess not having any 12-marker matches is not that unusual. On the other hand, I guess the distribution is not random, or nobody would have any 12-marker matches. I guess I'll have to go read a book. Thanks for your help.

          Mike

          Comment


          • #6
            Reasons to upgrade

            Originally posted by lgmayka
            It is not unknown for an 11/12 near-match to grow into a 24/25, and even 36/37, match. IMHO, a lack of exact matches is not a reason not to upgrade.

            Besides, even loose near-matches such as 32/37 may be able to tell you about your ancestry, even if it is out of the range of conventional genealogy.
            Yes, I overlooked the fact, also noted by someone else, that a genetic distance of say 1 at 12 might remain 1 at 25 or 37. So I agree that's not a reason not to upgrade.

            Another reason I hesitate is that my projected haplogroup does not match that of anyone in my surname project. So that seems to be another reason why upgrading is not likely to help me with "conventional genealogy."

            On the other hand, I can see where ancestry outside the range of conventional genealogy is interesting too, so maybe I'll go ahead for a different reason than the one I started with.

            Mike

            Comment


            • #7
              Originally posted by Mike Carroll
              3 billion at least. Wow. So 1% of that is, what, 30 million, making 25,000 or so a tiny fraction of 1%. I guess not having any 12-marker matches is not that unusual. On the other hand, I guess the distribution is not random, or nobody would have any 12-marker matches. I guess I'll have to go read a book.
              Right, our Y-haplotypes are not randomly generated each generation. Rather, they are copied from our father with a very small number of random variations (think "random walk" instead of "random number generator").

              The actual number of different 12 marker haplotypes in the world is surely far less than the number of possible ones.

              Comment


              • #8
                Originally posted by Mike Carroll
                Another reason I hesitate is that my projected haplogroup does not match that of anyone in my surname project. So that seems to be another reason why upgrading is not likely to help me with "conventional genealogy."
                Of course, an adoption or surname change along your patrilineal line is also possible. You may then have to use Ysearch to find the ancestral surname, and you may need 37 markers to persuade that surname's project to admit you.

                Comment


                • #9
                  Ancestral surname via ySearch

                  Originally posted by lgmayka
                  Of course, an adoption or surname change along your patrilineal line is also possible. You may then have to use Ysearch to find the ancestral surname, and you may need 37 markers to persuade that surname's project to admit you.
                  I don't disagree with anything you say, but I'm not sure I follow. In the Carroll surname project, I am at the moment the only I1B, but the project has only about 30 members. A couple of my near-matches are Crowleys, and there are at least 6 I1b's in, for example, the Crowley Clan surname project. But that project has more members. And the predominant haplogroup in both the Carroll & Crowley Clan projects is R1b1, not I1b.

                  Aren't these samples too small to use them to find an ancestral surname? If I have a genetic distance of 2 at 37 from, say, one of 60 Crowleys, but none that close to any of 30 Carrolls, does that indicate an ancestral surname event, or only that not enough Carrolls have been tested yet?

                  Mike

                  Comment


                  • #10
                    Originally posted by Mike Carroll
                    Aren't these samples too small to use them to find an ancestral surname? If I have a genetic distance of 2 at 37 from, say, one of 60 Crowleys, but none that close to any of 30 Carrolls, does that indicate an ancestral surname event, or only that not enough Carrolls have been tested yet?
                    Both, I would say. A genetic distance of only 2 at 37 markers generally does indicate a common patrilineal ancestor within a genealogical time frame (the adoption of surnames and written records in the British Isles). However, if the surname-altering event occurred in, say, the 17th century, then it is true that you will eventually encounter matches with your own surname--specifically, others who also descend from that 17th-century ancestor with the adoptive surname.

                    Comment


                    • #11
                      How Many Marker Combinations in 12 Marker Test?

                      In response to the question as to being tested for 25 or 37 markers in the absence of any exact matches at 12 markers, I would like to offer my limited experience. I had no exact matches at 12 markers within my surname from early 2004 until the fall of 2006. However, when I opted to have FTDNA show all exact 12 marker matches, regardless of surname on my FTDNA personal results page, I had maybe 55. Now I am up to 250 in total exact 12 marker matches. The first exact match within the surname appeared about 3 months ago, and about 8 months ago I got the first 11/12 match within the surname. Those are the only two close matches I have within the surname and the exact match is descended from one of my GGF's brother.

                      As to non-matching haplogroups within the surname project, I believe much of the problem is that members don't enter their haplogroup on the Ysearch page. That is too bad because, according to the Ysearch page, the McCowns haplogroups range from unknown to R1b1c. I don't believe that we McCowns have entered our data correctly and kept it up to date. First, if FTDNA predicts your haplogroup it most likely is your haplogroup. Mine was first predicted as R1b then R1b1 and currently R1b1c and that is a consistent progression. None of the McCowns report any haplogroup except some version of R1b, if you exclude those who haven't reported their haplogroups.

                      Comment


                      • #12
                        How Many Marker Combinations in 12 Marker Test?

                        In my previous response I ran out of space before I got around to the issue of the merits of going for the 25 and 37 marker upgrades. My experience at the time I upgraded to the 37 marker test was that I had no exact or close matches at 12 markers within the surname. I was very glad that I upgraded and recommend the same to you. What I found was the encouraging information that I had 8 matches of 23/25 markers and 5 matches of 33/37 markers, all outside of my surname and all of them Irish. The predicted Most Recent Common Ancestor for the surnames MacAuley, McGuire and Donahoe were 97+% for MacAuley and 96+% for McGuire and Donahoe 24 generations ago. However, the percentages were better than 50% much more recently but it gave me renewed hope for exact matches within the surname and raised a lot of questions. Also, those results are consistent with my exact haplogroup matches. Within haplogroup R1b1c, the rank order of exact haplogroup matches is first Irish, then Scottish and then English.

                        Comment

                        Working...
                        X