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200+ cMs in common but can't find the match

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  • 200+ cMs in common but can't find the match

    Hi all, hoping someone with a little more expertise with this DNA stuff might be able to shed some light on this for me. I have a match on FTDNA that is driving me crazy. According to FTDNA, we share over 200 cM, which is quite a bit more than any other match I have. In order from largest to smallest, the large-ish individual segments we share are (in cMs): 46, 23, 19, 19, 17, 13, 12, 12, 12, 11. Perhaps I should say that the largest segment, the 46 cM segment, is on chromosome 1 and crosses that "SNP poor region" that is not tested, so I'm not sure, perhaps it should not be considered one segment, although FTDNA calls it one segment. At any rate, FTDNA gives us a relationship range of 2nd-3rd cousins, and I know that the FTDNA relationship estimates can't exactly be taken as gospel but it at least seems reasonable based on the amount of shared DNA. There does not appear to be a match among any of our great great grandparents, although some of them clearly knew each other and were from the same small area in Ireland. Perhaps if we were able to go one generation back, maybe we would see a match, but would one set of 3rd great grandparents be enough to share 200 cMs? What if we shared TWO sets of 3rd great grandparents (although that doesn't seem likely based on our trees)? It just seems strange to me and a little frustrating that although we share this much DNA, I can't track down the connection! Does anyone have any words of wisdom for me, or tell me what I might be able to expect based on sharing this many cMs, with what seem to be a couple of fairly long segments?

  • #2
    You may need to go farther back to find the common ancestor. In my case, the person who I share the most cM with, 159.2 cM, would be expected to be my 2nd-3rd cousin. In fact, he is my 5th cousin 1x removed (although there might be another connection somewhere--when you get that far back, especially if it is a small geographic area, you tend to find cousin marriages and the same ancestor reachable in more than one way.


    • #3
      A match in the 200 cM range is extremely unlikely to be a false positive, and it certainly should be somewhere in the 2nd to 3rd cousin range. It seems to me that the most likely explanation for this situation is that one or both of the pedigrees are in error! Both pedigrees should be examined critically. A search should be made for additional cousins who have been or who could be tested, so you can get a better idea of where the connection is.


      • #4
        I have witnessed a similar scenario: two trees were declared to be separate. A surname of the first husband was taken to be a maiden name and together with a slightly different spelling of the first name made it a different person. And of course the researcher for that tree could not find parents/birth certificate for such a person...


        P.S. We knew that there had be something as the two oldest living members claimed that they were told in their childhood that they were cousins. Younger ones dismissed that, as they are clearly not even 2nd cousins. They are 3rd cousins once removed...


        • #5
          Thanks everyone for your input, I enjoy hearing your experiences. There is actually a giant hole in my match’s tree in that he has one grandparent whose name he knows, but he knows nothing else about him. However, my match’s cousin via this same grandparent took the test, and does not show up as a match for me there (I took my test at Ancestry and imported to FTDNA), so I have to think that our connection is probably not through this line. I’ll go back and review the records and see if anything looks fishy, and will keep plugging away at it!


          • #6
            I have a the same problem!

            I have a very similar match. I have a very close match 1st cousins once removed or 2nd cousins, by estimate of match.

            Largest segment = 53.2 cM
            Total of segments > 7 cM = 376.3 cM
            Estimated number of generations to MRCA = 2.6

            I am in contact with my "cousin" and we have researched his family tree to the most distant family known, no match on trees. I have ran his surnames thru my tree search engines on multiple sites, nothing. We do share common matches, but no known matches in surnames

            One fact to note is I do not know my biological father, so we are assuming our connection is via my father.

            What is confusing is after running all his surnames, everyone in his tree, I get no matches but him.

            I have ran some Chromosome testing and found one seperate chromosomes we match to different groups of people, my cousin and I, then XXXXX,another chromosome my cousin and I and XXXXXXXXXX. It seems like there are multiple DNA connections.

            Anyone ever seen this before? Can you create a closer match by connecting via separate ancestors to show a false close match?

            Thanks, Ron
            Last edited by GeoMetric; 27 February 2015, 05:14 PM.


            • #7
              if one has multiple distant common ancestor pairs with a match it leads to a higher probability of a greater amount of shared DNA which will be interpreted as a closer estimated relationship. A continuous matching segment is relatively unlikely to come from multiple common ancestors, but if one has multiple smaller segments they could very well each be from a different line. This also comes into play when there are cousin marriages along the relevant line. I have one match who has quite a few 2nd cousin marriages tying back in to the same ancestral line and I have a 4th cousin marriage on my side. Even though I haven't found any evidence of any single relationship path closer than 6th cousins 1x removed, the match has shared DNA equivalent to about a typical 3rd-4th cousin range.


              • #8
                In these cases the simplest answer is someone's great grandfather went wandering.

                Instead of trying to match surnames, match geographies and timelines.


                • #9
                  I agree that possible cousin marriages in the distant past are most likely not the situation here. Some people can share large amount of total cM's with people and not necessarily be closely related as many will be small segments. Here, there are many segments shared above 10 cM (10 in all). This is a close relationship, probably 2nd cousins or second cousins once removed. One or both paper trees might not match the actual biological family tree.