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Y-DNA matches with a genetic distance of 6 and 7. How certain can I be?

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  • Y-DNA matches with a genetic distance of 6 and 7. How certain can I be?

    Hi. I only have two 67 marker matches, both from the British Isles, which is a surprise to me as my earliest known ancestor, Niels Willumsen Storalmenning (b. 1620), lived in the northern part of Norway. (See https://www.familytreedna.com/public...frame=yresults)

    These matches are, however, at a genetic distance of six and seven steps.

    I also have a 37 marker match with someone from Scotland, at a genetic distance of four steps. But he only tested 37 markers.

    How certain is it that we actually share a common ancestor within the timeframe given in the TiP report? Could it, perhaps, be a spurious resemblance?

    Thanks in advance,

    Ivar

  • #2
    You probably do share a common ancestor, but not in any recent timeframe. Could be 1000s of years ago.

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    • #3
      I would not want to base any genealogical conclusions on such a match.

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      • #4
        Originally posted by spruithean View Post
        You probably do share a common ancestor, but not in any recent timeframe. Could be 1000s of years ago.
        But the Tip calculator reports 88,45, 88,95 and 97,57% probability that I share a common ancestor within 16 generations. Am i being mislead by FTDNAs calculations?

        And why are there no matches with people from Scandinavia at 37 and 67 markers?

        My haplogroup is I-M223>M284-Isles/Sc.
        Last edited by Ivar Kristensen; 24th October 2017, 09:48 AM.

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        • #5
          99%

          The TIP calculated is pretty accurate at 67 markers.

          there is a 99% probability you have a common ancestor within the last 24 generations, or within the last 700 years with your 67 Marker matches.

          have they done the 111 marker testing ? This would be more accurate.

          24 generations ago you would have 16,777,216 Great Grandparents, so it is not very meaningful to determine your ancestry. It is possible that one of your 16 million Great Grandparents was from the British Isles and the others were from another area. Also possible some of your ancestors migrated to the British Isles, via the Norman invasion. The The Norwegian king Harald Hardrada invaded northern England in September 1066 and thus many from the UK will have Y chromosomes from the Norwegian invaders..

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          • #6
            Originally posted by Ivar Kristensen View Post
            And why are there no matches with people from Scandinavia at 37 and 67 markers?
            Maybe not enough people from there have tested. Maybe that lineage is no longer at Scandinavia. Maybe it "daughtered-out", meaning they stop having sons so the Y-DNA from that specific group was not passed down.

            You could try to find distant paternal cousins or potential cousins and get them to test to see if they match you. There is also the possibility of an NPE (non-paternity event) where someone raised a son that was not biologically their own.

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            • #7
              Originally posted by jova99 View Post
              have they done the 111 marker testing ? This would be more accurate.
              The person I match with a genetic distance of 6 steps have. And his last name is supposedly of Norman origin http://www.bartlettname.net/england.html

              The problem with the norman theory is my haplogroup. I-M223>M284 is very rare in Norway. Just look at the results from the I-M223 project. I'm in the middle of a bunch of people from England, Ireland and Scotland.
              Last edited by Ivar Kristensen; 24th October 2017, 11:24 AM.

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              • #8
                Originally posted by The_Contemplator View Post
                You could try to find distant paternal cousins or potential cousins and get them to test to see if they match you.
                That's what I'm trying to do. Without any luck so far.

                Originally posted by The_Contemplator View Post
                There is also the possibility of an NPE (non-paternity event) where someone raised a son that was not biologically their own.
                I have been speculating a lot about that after I got my results
                Last edited by Ivar Kristensen; 24th October 2017, 11:11 AM.

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                • #9
                  Originally posted by Ivar Kristensen View Post
                  These matches are, however, at a genetic distance of six and seven steps.

                  I also have a 37 marker match with someone from Scotland, at a genetic distance of four steps. But he only tested 37 markers.

                  How certain is it that we actually share a common ancestor within the timeframe given in the TiP report? Could it, perhaps, be a spurious resemblance?
                  FTDNA's "matches" list shows a lot of matches that FTDNA does not consider as a "match" under it's genetic distance interpretation guidelines. Depending on which version of FTDNA's guidelines you look at, a GD of 6 or 7 on a comparison of 67 markers or a GD of 4 on a comparison of 37 markers means that, for men who share the same surname, they probably have a common ancestor in the genealogical time frame (which FTDNA defines as 15 generations). See 67 marker guidelines and 37 marker guidelines. The implication is that a GD or 6 or 7 on a 67 marker comparison or a GD of 4 on a 37 marker comparison does NOT mean that the men two men probably share a common ancestor within the genealogical time frame. As the guidelines state, the fact that men do or do not have the same surname is important information that shifts the probabilities. If two men do not have the same surname, the chances are significantly greater that the "match" is the result of convergent mutations of STRs. The same logic should also hold for TiP calculations, so I would discount the TiP probabilities if the surnames are different. There is no doubt a relationship somewhere in the past, but could be 1000s of years.

                  The most likely reason you have matches from the British Isles and none from Norway is that a lot more men from the British Isles (and certainly of British Isles descent) have been tested at FTDNA.
                  Last edited by TwiddlingThumbs; 24th October 2017, 12:13 PM.

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                  • #10
                    Ok, thanks TwiddlingThumbs!

                    "5 or 6. Related. A 61/67 or 62/67 match between two men who share the same surname (or a variant) means that they may to share a common ancestor within the genealogical time frame. The common ancestor is probably not recent, but may still be within the range of most well-established surname lineages in Western Europe."

                    I don't get why they have to share the same surname (or a variant). Doesn't surnames change completely in many cases?
                    Last edited by Ivar Kristensen; 24th October 2017, 12:33 PM.

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                    • #11
                      Originally posted by TwiddlingThumbs View Post
                      The most likely reason you have matches from the British Isles and none from Norway is that a lot more men from the British Isles (and certainly of British Isles descent) have been tested at FTDNA.
                      But shouldn't I be "closer" to, or have distant matches with other norwegians or scandinavians in the same haplogroup? Is it wrong to suppose that the genetic distance to them should be shorter than to people from the British Isles?
                      Last edited by Ivar Kristensen; 24th October 2017, 12:53 PM.

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                      • #12
                        111 marker testing may help

                        the 111 market testing may clarify the Genetic distance for you.

                        among my 22 matches at 67-markers only 4 have done the 111 marker testing, and none of them match me at 111 markers.

                        these 4, which are a GD of 6 or 7 at 67 markers, are not a match to me at 111 markers...they are in reality a GD of 10 ,11, 12 and beyond.

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                        • #13
                          yes, but is it worth it?

                          I'm really disappointed. It feels like I'm on an island of my own. No "real" matches to anyone. How depressing. I guess I wasted my money.
                          Last edited by Ivar Kristensen; 24th October 2017, 02:36 PM.

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                          • #14
                            It may not be worth updating. However, I wouldn't see your lack of matches as a waste of money. Getting tested does not guarantee that you will have meaningful matches. My own Y67 has no matches at any level. I don't see it as a waste. It just means I am the first in my lineage to test. Now I just have to wait or actively recruit to get matches. You may need to wait a week, a decade, or more. At least now you have a flag planted where those matches can find you.

                            In my case, I simply focused on other branches of my family tree. I had my mother's brother tested and that has meaningful matches I can pursue for my research. I've tested a few other relatives as well. So while I wait for any match on my own Y line, I can still work on other branches.

                            Another option is to take an autosomal DNA test like Family Finder. That will give you matches from all branches of your tree. Maybe some of your paternal cousins will show up there. Then you can recruit them to take a Y-DNA test to see if they are part of the same lineage. I've found paternal cousins on other genealogical sites. Turns out they are out there but just haven't tested or aren't that interested in genealogy.

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                            • #15
                              My own complete lack of convincingly close Y-DNA matches (Y-111 and Big Y) has allowed me to ignore all of the other McCoy families who have tested. Their McCoy genealogy is simply not my McCoy genealogy. I can safely move on to other genealogical problems.

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