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significance of twelve-marker matches

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  • significance of twelve-marker matches

    My brother is a participant in a sixty-five member DNA group project. While he matches two known cousins well enough to be considered related to them, we are puzzled by the number of participants of the same surname who match eleven out of twelve markers, but don't match well enough in the extension to twenty-five markers to be related. A little over fifteen percent of the group participants fall into this category. Would there be anything significant at all about this many non-related, same surname participants having an eleven out of twelve marker match?

  • #2
    Hi Jane

    12 markers just isn't really enough markers tested to be sure of a true DNA match, unless you have a paper trial proving the kinship first.

    In the Locke DNA project, when we had men have a 12 marker match and they didn't have a paper trial linking thier family's together, I suggested all participants involved upgrade to at least the 25 marker level or higher.
    Many found out the hard way that at the 25 marker level or higher, they found out that they weren't in any way related.

    A lot can change between the 13th to 25th markers. Unless your brother is in a rare Haplo Group, or has a solid paper trial linking him to his cousins, I wouldn't rely on a 12 marker kit. It is worth upgrading to be sure of a good match.

    Even with a solid paper trail, it is still nice to be able to see everyone involved, upgraded to a higher marker level for no other reason then to see which branches had certain mutations. DNA testing doesn't stop with the 12 marker kit, there is much to be learned by upgrading and getting the cousins upgraded too.

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    • #3
      Originally posted by Jane K
      My brother is a participant in a sixty-five member DNA group project. While he matches two known cousins well enough to be considered related to them, we are puzzled by the number of participants of the same surname who match eleven out of twelve markers, but don't match well enough in the extension to twenty-five markers to be related. A little over fifteen percent of the group participants fall into this category. Would there be anything significant at all about this many non-related, same surname participants having an eleven out of twelve marker match?
      Jane, I'm not nearly as knowledgable as many of the people who write on the Forum, but I'd suggest that he goes to at least 37 markers because there's a relatively high number of fast moving markers in the first 25 that FTDNA routinely tests. If he upgrades to at least 37, which includes more slow moving markers, he may (or may not) find that he shares a higher percentage of values in common with the other participants than he does now with the 25.

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      • #4
        Thanks for your advice. My brother's results do include thirty-seven markers, and the closest matches to his results are with two people with different surnames. The two cousins that he matches only have results for twenty-five markers, but we're basically sure of the kinship there anyway. I reiterate, we still think that more than fifteen percent of all the participants in our surname group having a match with my brother on the first twelve markers is a large percentage, whether significant or not.

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        • #5
          Originally posted by Jane K
          Thanks for your advice. My brother's results do include thirty-seven markers, and the closest matches to his results are with two people with different surnames. The two cousins that he matches only have results for twenty-five markers, but we're basically sure of the kinship there anyway. I reiterate, we still think that more than fifteen percent of all the participants in our surname group having a match with my brother on the first twelve markers is a large percentage, whether significant or not.
          As Vinnie and Donald have both posted, you won't know the significance of the 12 marker matches until they upgrade to 37 markers. Some will fall away to not being close matches any longer, while some will remain close matches and be significant.

          You say the surname project has 65 members, which is probably at least a middle-size project. That implies to me that the surname involved is not uncommon. So some of the 12 marker matches will probably fall away at 37 markers, since more common surnames don't have an origin in just one paternal line.

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          • #6
            real vs. imagined...

            The big weakness of tracing Y-DNA lineages is the tendancy for "non-paternity events" to occur over the generations. No one in the olden days ever dreamed that some day DNA testing would reveal their indiscretions.

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            • #7
              I'm not doing a very good job of making myself clear, so let me attempt this one more time. My brother matches over fifteen percent of the participants in his DNA project group on the first twelve markers, but DOESN'T match well enough with those in the fifteen percent group to be considered related on the EXTENDED marker results; i.e., he is NOT related to those same surname participants that he matched on the first twelve markers.

              My inquiry is this: Is the twelve marker match with these other participants significant in any way, even though extended marker results show no kinship? It may be a fairly common occurrence to have this many matches on the first twelve markers with other same-surname participants and not be related. My limited experience with DNA testing on other lines I connect to have not had this same result. In fact, we've had no first twelve marker matches with the same surnames who didn't match in the extended marker results.

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              • #8
                Originally posted by Jane K
                My inquiry is this: Is the twelve marker match with these other participants significant in any way, even though extended marker results show no kinship? It may be a fairly common occurrence to have this many matches on the first twelve markers with other same-surname participants and not be related. My limited experience with DNA testing on other lines I connect to have not had this same result. In fact, we've had no first twelve marker matches with the same surnames who didn't match in the extended marker results.
                It would help if you gave us a link to the project's website and identify which haplotype is your brother's. Then we could see exactly what is the haplogroup involved and what are the marker values in the first 12 markers, which may be very common.

                I suspect that your brother and his matches at 12 markers are all R1b1c, which is the most common haplogroup among those of European ancestry. It's not uncommon for an R1b1c with relatively common values in the first 12 markers to have lots of close or exact matches, even with others who have a different surname. But most of these matches don't hold up at 37 markers.

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                • #9
                  Our Holt family project site is www.holtfamilydnaproject.com and my brother's ID number is 31961. One of the three matches with him, given with red lettering for "PLeasant," is a non-Holt; the other two are second and third cousins. Those twelve marker matches can be found directly below our Pleasant Holt line. Those matches are for eleven out of twelve markers, as is the case for those in our lown line who continue to match beyond twelve markers and are considered related. The answer to my question may be simply that it's coincidental. I just thought it strange that so many more Holts match my Holts on the first twelve markers than do any other surnames.

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                  • #10
                    Originally posted by Jane K
                    Our Holt family project site is www.holtfamilydnaproject.com and my brother's ID number is 31961. One of the three matches with him, given with red lettering for "PLeasant," is a non-Holt; the other two are second and third cousins. Those twelve marker matches can be found directly below our Pleasant Holt line. Those matches are for eleven out of twelve markers, as is the case for those in our lown line who continue to match beyond twelve markers and are considered related. The answer to my question may be simply that it's coincidental. I just thought it strange that so many more Holts match my Holts on the first twelve markers than do any other surnames.
                    I looked at the results page for your surname's project, but didn't take the time to compute how closely the Robert's below your Pleasant line match your line at 37 markers. But it was as I suspected, that your line and the close matches are all R1b1c and have very common marker values in the first 12. In fact, the only somewhat unusual marker you have in the first 12 is DYS390, at which you have 25, while the general R1b1c modal is 24. The other 11 values are the commonest values.

                    I went to ysearch and did a search for your 12 marker haplotype and got 256 exact matches. Obviously, there are not 256 people in ysearch who are in the same paternal line as you. They just happen to share the same common values in the first 12 markers, including DYS390=25, which is not so common.

                    Then I did a search for matches to your 37 marker results. At a genetic distance of 7, you only have 26 matches. This is the principle those who have responded to you have mentioned, your matches at a genetic distance (GD) of 7 total just 26, indicating that most of those who match you exactly at 12 markers have fallen away at 37 markers. A GD of 7 or even 6 does not indicate any recent common ancestor. That's probably indicating a common ancestor before surnames came into widespread use, probably 1,000 or more years ago.

                    However among those matches with GD of 7 or less at 37 markers, you have 3 very close matches, indicating that they share a common ancestor with your paternal line within a genealogical timeframe. None of these three have either the Pleasant or Holt surname. Here's a link to a comparison with these 3 haplotypes on ysearch - http://tinyurl.com/2yrv7z The two with surname Evans match you perfectly at 37 markers. It's likely that your line and theirs has had a common paternal line ancestor in the last 100 years, possibly a bit more. The third one, Poore, is a GD of 2 from you. It's likely that your line and his share a common paternal line ancestor in the last 400 or so years.

                    You should contact them through their ysearch accounts and see if they will compare their family trees with yours. You may find ancestors who lived in the same time and place, indicating that's roughly where and when the common ancestor lived.

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                    • #11
                      Originally posted by Jane K
                      My inquiry is this: Is the twelve marker match with these other participants significant in any way, even though extended marker results show no kinship? It may be a fairly common occurrence to have this many matches on the first twelve markers with other same-surname participants and not be related.
                      Jane,

                      I think the answer is "no". Your brother is a close match with only several other folks (37143,49642,and 85019), all of whom list "Pleasant" as the ancestor.

                      However, the distance you see with at extended tests tells you that your relationship to all the rest of the project members is VERY distant (at least 1,000 to 2,000 years). The 12 markers matches , as others have mentioned, are merely a function of your brother being in the same haplogroup and nothing more so I wouldn't spend much energy on them.

                      I agree with Mike that you should investigate the non-surname matches that he found, if you are so inclined, especially if any of these families were near (in time and space) your Holt ancestors.

                      Vince

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                      • #12
                        I've already been in touch with those who have thirty-seven marker matches with my brother. There is only one Evans match; for some reason the same person's DNA results are listed twice. The contact for the Evans man is as puzzled as I am, and we have not been able to come close to making a connection between our two lines. The other person, Mr. Poore, knows there was an illegitimacy in his line, and this occurred in the same area where my Holts were living. As far as I can tell, I've left no unexplored avenues. This is reason for my inquiry about the twelve marker matches with so many unrelated Holts. Out of all the non-Holt surnames that match my brother on twelve markers, there isn't an abundance of any particular surname, just the large amount (in my opinion) of Holts.
                        An almost identical situation exists, as far as DNA testing goes, with another of my lines. I refer to the DNA bricks added to my existing "brick walls." Hopefully in the near future, there will be yet another DNA match to provide some positive results.

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