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if X and Y match at FF, do they both descend from Z?

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  • if X and Y match at FF, do they both descend from Z?

    We'll call my mother Mama.
    We'll call her male 1st cousin Lloyd.

    Mama's mother and Lloyd's father were siblings. We had Lloyd's Y-DNA test done because we want to trace their mutual grandfather. Lloyd has never had any meaningful Y-DNA matches with anyone of the same surname. He and Mama have a solid match on their Family Finder tests.

    So here's my question: do FF matches provide evidence that they're both descended from the same grandfather? If so, is it possible to see it graphically in the chromosome browser?

    If not, is there a test can we do to determine if they both had the same grandfather? (So far, we've had FF and mt-DNAFS for Mama. Lloyd has had FF, Y-DNA 67, and mt-DNA.)

    Lloyd was 1st born in his family. Since he hasn't had a meaningful surname match, I wonder if there was an NPE. He does have another living brother, but I hate to bother them. All 3 people here are 85+ years old.

    One more thing: is there a simple program online somewhere that will show the answer to this type of question?

    K.
    Last edited by GoofusBroadway; 29 October 2014, 09:54 PM. Reason: adding question

  • #2
    Originally posted by GoofusBroadway View Post
    We'll call my mother Mama.
    We'll call her male 1st cousin Lloyd.

    Mama's mother and Lloyd's father were siblings. We had Lloyd's Y-DNA test done because we want to trace their mutual grandfather. Lloyd has never had any meaningful Y-DNA matches with anyone of the same surname. He and Mama have a solid match on their Family Finder tests.

    So here's my question: do FF matches provide evidence that they're both descended from the same grandfather? If so, is it possible to see it graphically in the chromosome browser?

    If not, is there a test can we do to determine if they both had the same grandfather? (So far, we've had FF and mt-DNAFS for Mama. Lloyd has had FF, Y-DNA 67, and mt-DNA.)

    Lloyd was 1st born in his family. Since he hasn't had a meaningful surname match, I wonder if there was an NPE. He does have another living brother, but I hate to bother them. All 3 people here are 85+ years old.

    One more thing: is there a simple program online somewhere that will show the answer to this type of question?

    K.
    When you look at Mama's Family Finder match with Lloyd, how many "Shared cM" do they have in common? This will be the number right before the Ancestral Surnames when you click on Family Finder Matches.

    Comment


    • #3
      @GoofusBroadway: Three short comments

      Please follow Kathy's instructions.

      Then take a look at the table in Autosomal DNA statistics http://www.isogg.org/wiki/Autosomal_DNA_statistics You will easily realize which relationship range your mother and your uncle are in.

      Why, under the circumstances you had described, a lack of a Y-DNA match might even remotely suggest a NPE? That could only be suggested if you had Y-DNA of their great-grandfather. You should be able to verify a NPE using Family Finder results of your mother and your uncle. If the results suggest it, then you really need to see your uncle's brother Family Finder test. Please share with us (if you can) Shared cM, as further advice depends on it.

      Comment


      • #4
        Originally posted by dna View Post
        Please follow Kathy's instructions.

        Then take a look at the table in Autosomal DNA statistics http://www.isogg.org/wiki/Autosomal_DNA_statistics You will easily realize which relationship range your mother and your uncle are in.

        Why, under the circumstances you had described, a lack of a Y-DNA match might even remotely suggest a NPE? That could only be suggested if you had Y-DNA of their great-grandfather. You should be able to verify a NPE using Family Finder results of your mother and your uncle. If the results suggest it, then you really need to see your uncle's brother Family Finder test. Please share with us (if you can) Shared cM, as further advice depends on it.
        Any information on FTDNA's criteria for Ashkenazis?

        Comment


        • #5
          Originally posted by josh w. View Post
          Any information on FTDNA's criteria for Ashkenazis?
          Good question, I have been asking myself the same thing.
          I have some 170cm matches that are not close matches for sure because the largest segment is about 10cm...

          I think that there are enough Ashkenazis that took the test to do the statistics. Somebody need to do it....

          My rule of thumb is: less than 200cm shared or less than 45cm longest block, don't worth much for Ashkenazis.

          Comment


          • #6
            Thanks for all the input. Mama and Lloyd share 900cM.

            Lloyd isn't my uncle, he's Mama's 1st cousin... son of my maternal grandmother's brother.

            Thanks for the link to the ISOGG info. Seems to be a very useful webpage. With 900cM shared, it looks like both of them are descended from the same set of grandparents. Am I interpreting this correctly?

            dna:
            re: NPE... I'm new to most of this and an NPE seemed (to me) a possibility, since Lloyd wasn't getting ANY good matches of the same surname -- even at 67 markers.

            kathy

            Comment


            • #7
              Just to add a bit of perspective, the following are what my Father and his siblings share with their 1st cousin. Who they share the same paternal grandparents.

              My father to cousin - 947cM
              My Uncle 1 to cousin - 891cM
              My Uncle 2 to cousin - 793cM
              My Aunt to cousin - 876cM

              If there was a NPE, I would think it happened prior, either your Grandmothers father was a result of NPE, or one of his paternal ancestors.
              I would safely assume your grandmother and llyod's father were full siblings.

              Comment


              • #8
                I'm sorry Kathy for my uncle... He is of course your first cousin once removed. However, in the family setting I would never dare to address cousins of my parents other than aunt or uncle. And forgot that here we are trying to stay factual and accurate.

                You had asked about programs... There very few automated procedures in the genealogical research. However, I am convinced that, in a year or two, standard genealogical programs would be showing not only the most probable amount of DNA shared between any two people in the tree, but also the possible range of shared DNA for any two people in the tree, and the probability that shared DNA could be detected (very useful for selecting potential testers).

                And the above brings me to your question about the relationship. As you had seen with around 850cM shared (e.g. 900cM) there is more than one possibility. You have to know something more than just DNA. Luckily for you, you did.

                NPE. That was just nicely answered. Let me only repeat, that FTDNA does not have samples from everybody, so you are not guaranteed any matches... (Unless of course you tested two members of the family, to check their story .)

                Comment


                • #9
                  Just for the purposes of an example I'll share this info about my paternal grandmother and one of her 1st cousins. They are half 1st cousins through one of their grandmothers. My grandmother is descended from a son of the first marriage, the cousin from a daughter of the 2nd marriage.

                  FTDNA predicted that they are 2nd cousins based on the following: Total shared cM = 403, Longest block = 66.

                  I haven't yet tested any full 1st cousin relationships on any branch of my tree so I have nothing to compare this to. (I'll have a set early in the new year.) However, this example shows you the difference when two cousins share only one grandparent.

                  Comment


                  • #10
                    This is all very useful information. Thank you all. I feel much more confident about the match now.

                    Still not happy with the "no matches with the surname" bit, but that'll just have to come later, I guess. Maybe no one's in the db just now.

                    Thanks again,
                    Kathy

                    Comment


                    • #11
                      Originally posted by GoofusBroadway View Post
                      [----] Still not happy with the "no matches with the surname" bit, but that'll just have to come later, I guess. Maybe no one's in the db just now.

                      Thanks again,
                      Kathy
                      So there are exact matches..., just the surname is different? At what marker level (12, 25,37, 67, 111)?

                      Comment


                      • #12
                        Originally posted by GoofusBroadway View Post
                        Lloyd has never had any meaningful Y-DNA matches with anyone of the same surname.
                        In this case, the next step is to answer this question -- and the answer will then determine how to proceed next:
                        Do all/most of the matches have the same surname (ie, is your kit the odd one out?) OR do all/most of the matches have a variety of surnames?


                        1) If all/most matches have the same surname, except for you:
                        An NPE is the most likely scenario, and there are some things you can do to research this:
                        • Research where/when your surname crossed paths with the other surname. Look at neighbors in census records, etc. Keep in mind that the NPE could be several or many generations back.
                        • Recruit a distant cousin from the same paternal line to test -- the most distant cousin you can get. This will help you narrow down when the NPE occurred. If the distant cousin matches, then you know the NPE happened earlier than the common ancestor with your distant cousin. But if the distant cousin doesn't match, then the NPE happened more recently.


                        2) If all/most matches have a variety of surnames:
                        This typically indicates that inherited surnames have come into use more recently on your direct paternal line, so don't immediately assume an NPE. Some things to do for further research:
                        • Look at how close or distant the matches actually are. If you have 0,1,2-step matches at 67 markers with different surnames, then surnames were adopted very recently (past 200-300 years, perhaps). If you don't have close matches and your different-surname matches are 5,6,7 steps away, then surnames were probably adopted further back (past 300-500 years, perhaps).
                        • Recruit a distant cousin from the same paternal line to test -- the most distant cousin you can get. Assuming the distant cousin matches, this will serve to confirm your paper trail, confirm that the original test results were correct and provide more evidence that there hasn't been an NPE.


                        Hope this helps.

                        Elise
                        Last edited by efgen; 1 November 2014, 03:36 PM.

                        Comment


                        • #13
                          My great-grandfather (grandfather of Mama and Lloyd) used two different surnames during his lifetime: Lloyd and Pierce.

                          We're unsure which (if either) was his real surname, although he told his family that his father's name was William Pierce and his mother was Annie Lloyd. By all accounts, he was "a great storyteller". So... it's possible he made up the name. The surnames of his matches are all over the board, but most seem to be of Scottish origin.

                          Here are my mother's cousin's y-dna matches that are visible to me:

                          AT 12: 0 Lloyd, 8 Pierce/Pearce
                          113 exact matches
                          249 with GD=1

                          AT 25: 0 Lloyd, 0 Pierce
                          2 with GD=1
                          80 with GD=2

                          AT 37: 0 Lloyd, 0 Pierce
                          1 with GD=2
                          4 with GD=3
                          57 with GD = 4

                          AT 67: 0 Lloyd, 0 Pierce
                          2 with GD=4
                          8 with GD=5
                          35 with GD=6
                          80 with GD=7

                          Comment


                          • #14
                            Of the 97 y-dna matches he has at 67 markers:

                            4 Campbell at GD=7
                            4 Ferguson at GD=4 through 7
                            2 McCallum at GD=6
                            3 McCoy at GD=6-7
                            4 McDonald GD=6-7
                            5 McFarland/McFarlane/McFarlin GD=6-7
                            4 McPherson GD=5-7
                            3 Moore, GD=6-7
                            2 Norton, GD=6-7
                            3 Patterson, GD=6-7
                            2 Rock, GD=6-7
                            2 Rogers, GD=7
                            2 Turner, GD=7

                            The other 57 matches are all singletons.
                            The two matches he has at GD=4 are Ferguson and McIntosh.

                            Before you say anything: we've already ordered a Y-111.

                            Elsie: Based on your explanation, it looks like the 300-500 year time frame. Recruiting a distant cousin isn't possible at this time.

                            To the best of our knowledge, my great-grandfather was the only one of his family to come to the US. We have no other information on his birth family -- other than the names William Pierce and Annie Lloyd.

                            He did say he was born in Dublin. On the first census we have for him in the US, he was about 30 years old and stated his father was born in Wales. Subsequent censuses say Ireland.

                            It's a fascinating puzzle, but frustrating, too.

                            Kathy

                            Comment


                            • #15
                              Originally posted by GoofusBroadway View Post
                              Based on your explanation, it looks like the 300-500 year time frame.
                              Note: This timeframe is a very rough guesstimate on my part.

                              Here's where it came from:

                              Having matches with a myriad of surnames at the higher marker levels is completely normal for people with Ashkenazi ancestry, so I deal with this all the time in my own genealogy.

                              Ashkenazi Jews typically have had surnames for only 200-300 years, so we typically have very close matches -- even exact matches -- at 37 and 67 markers with different surnames.

                              Therefore, I'm assuming that if someone doesn't have very close matches at all, and matches other surnames more distantly, then the surnames were adopted longer than 200-300 years ago -- perhaps within 300-500 years.

                              Someone who is more familiar with Irish, Scottish and Welsh genealogy and adoption of surnames in those populations may have a better estimate than my very rough guesstimate

                              Elise

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