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  • Evaluating DNA tests, as related to genealogy.

    . I saw an item some time ago that FTDNA (whoever they are) has advised us that "even if you have a 25/25 match, and the SAME Surname, you may not actually be kin". Is this statement actually TRUE?? They go further to say that a 25/25 match with a person who has a different Surname does NOT indicate a relationshp. Would someone want to explain that to me ??? Sincerely, John D. Sanford, of CA.

  • #2
    Hi John,

    "FTDNA (whoever they are)".... this one I confess I did not quite understand...
    About your question regarding matches: here's where we post our comments about the different matches:
    http://www.ftdna.com/trs_explain.html
    http://www.ftdna.com/GDRules_25.html
    Max Blankfeld
    Vice-President and COO @ Family Tree DNA
    A Gene by Gene Company

    Comment


    • #3
      Originally posted by max
      Hi John,

      "FTDNA (whoever they are)".... this one I confess I did not quite understand...
      About your question regarding matches: here's where we post our comments about the different matches:
      http://www.ftdna.com/trs_explain.html
      http://www.ftdna.com/GDRules_25.html
      Hi Max,
      I went to both sites and they gave a great amount of information. Thanks for that. In the second paragraph of the 1st. site it says this; " . . .and the results match 12/12, there is a 99% probability that you two are related within the time frame included in the MRCA tables". What are those tables, can I see them, and what is that time frame in this case. Thank you for an answer to this, so I know what it means. Sincerely, John

      Comment


      • #4
        Originally posted by JohnSanford
        Hi Max,
        I went to both sites and they gave a great amount of information. Thanks for that. In the second paragraph of the 1st. site it says this; " . . .and the results match 12/12, there is a 99% probability that you two are related within the time frame included in the MRCA tables". What are those tables, can I see them, and what is that time frame in this case. Thank you for an answer to this, so I know what it means. Sincerely, John
        Here are the links for all the tables for the relevant matching possibilities:
        http://www.ftdna.com/faq2.html
        and, for more in depth info:
        http://nitro.biosci.arizona.edu/ftdna/TMRCA.html
        Max Blankfeld
        Vice-President and COO @ Family Tree DNA
        A Gene by Gene Company

        Comment


        • #5
          What does the colume "Views" Mean?

          Max, Thanks for the datails that I asked for. On this thread, I see that there are now "2 Replies", and the next column says "66 Views". I assume that the 2 replies relate to your 2 replies to my first message, Is that correct? Then it says there are now 66 views, What does that mean to you?
          Kind regards., I appreciate you as you are the only one who has actually tried to answer my questions! John Sanford, of CA.

          Comment


          • #6
            Re: What does the colume "Views" Mean?

            Originally posted by JohnSanford
            Max, Thanks for the datails that I asked for. On this thread, I see that there are now "2 Replies", and the next column says "66 Views". I assume that the 2 replies relate to your 2 replies to my first message, Is that correct? Then it says there are now 66 views, What does that mean to you?
            Kind regards., I appreciate you as you are the only one who has actually tried to answer my questions! John Sanford, of CA.
            You're correct about the 2 views that should be increased now... ;-)
            The 66 views means that the thread was seen 66 times by different people.
            Max Blankfeld
            Vice-President and COO @ Family Tree DNA
            A Gene by Gene Company

            Comment


            • #7
              Re: Evaluating DNA testing for Genealogy, again!

              -
              At the start of this "Thread", I asked a question that is still UNANSWERED.
              I have been told that. "even if you have a 25/25 match and the SAME Surname, you may not actually be kin " Is this statement actually TRUE?? This thread has been viewed 153 or more times by different people; and no one, including you 'MAX' in your responses, have answered the question with a simple YES or NO. I would like for someone to answer the question without all of the rationalizations that are given in the almost hopeful answers. Sincerely, John Sanford.
              -

              Comment


              • #8
                Re: Re: Evaluating DNA testing for Genealogy, again!

                Originally posted by JohnSanford
                -
                At the start of this "Thread", I asked a question that is still UNANSWERED.
                I have been told that. "even if you have a 25/25 match and the SAME Surname, you may not actually be kin " Is this statement actually TRUE?? Sincerely, John Sanford.
                -
                YES! You have been given many reasons why it is true.

                Comment


                • #9
                  Re: Re: Evaluating DNA testing for Genealogy, again!

                  Max sent you originally to a site that said "If you compare a 25 Marker result to another 25 marker result for the SAME surname, and the results match 25/25, then there is also a 99%
                  confidence that the two individuals are related…and at a much closer time interval then with the 12 marker test".

                  So I'd say what you read or saw was true. There's a 1% chance the two individuals are not related, by their own admission.

                  James B.

                  Comment


                  • #10
                    Evaluating DNA testing for Genealogy, again!

                    Originally posted by James B. Barnes
                    Max sent you originally to a site that said "If you compare a 25 Marker result to another 25 marker result for the SAME surname, and the results match 25/25, then there is also a 99%
                    confidence that the two individuals are related…and at a much closer time interval then with the 12 marker test". James B.
                    James.B, I have studied the "Understanding MRCA" closely and it says this: If you have matching markers of 25 of 25, you have only a "50% probability that the MRCA was no longer that 7 generations. ARE THEY WRONG? They also say that it is a 90% probability that it is no longer than 23 generations. Hmmmmm.
                    You apparently think that being related in say 30 generations, is useful to my own well researched genealogy database where I am only really concerned about the last 20 or so generations. John Sanford
                    -

                    Comment


                    • #11
                      John: If you match 25/25 you are probably related (90% chance) any time UP TO 23 generations. It could be within 20 or 18 or 15 -- or of course it has a 10% chance of being even further back than 23. Mutations are random and unpredictable. You could also be related very closely, if the regular research supports that. In fact, half of the time, the relationship is no further back than 7 generations. In other words, you are probably related, but now you need to do the "legwork" to find out exactly where and when.

                      Comment


                      • #12
                        Evaluating DNA testing for genealogy purposes?

                        - - - -
                        Hello Whitney,
                        After studying the DNA processes and the many messages by others, including your fine responses, I have come to a conclusion that this type of testing is of little real value for genealogy purposes. There are so many things that are said about the results of these tests that come out as ’it is possible, maybe, there is a 50% chance that you are probably related’, and other unclear comments. Of course, “you could be related to someone else, within the past 30 generations, or maybe 2000 years”
                        I am lead to believe that we are expected to spend significant amounts of money, with the hope of getting that kind of inexact rationalizations from some who are obviously eager to engage in ‘wishful thinking’, and who in fact do not have ‘a clue’ as to what to rely on FOR SURE. In your own recent statement, “you need to do the ‘legwork’ to find out exactly”, you clearly then understand what really needs to be done. And after that legwork has been done, then how can the DNA testing be considered useful – since that ‘solid research’ is the only thing that you can really rely on?? And then the result of that research is the only thing that you can confidently share with others, if you wish to actually help others with their genealogy records. Sincerely, John Sanford, of CA.
                        - - - -

                        Originally posted by whitkeen
                        John: If you match 25/25 you are probably related (90% chance) any time UP TO 23 generations. It could be within 20 or 18 or 15 -- or of course it has a 10% chance of being even further back than 23. Mutations are random and unpredictable. You could also be related very closely, if the regular research supports that. In fact, half of the time, the relationship is no further back than 7 generations. In other words, you are probably related, but now you need to do the "legwork" to find out exactly where and when.

                        Comment


                        • #13
                          John:
                          As a genealogist of many years experience, I'm sure you have learned not to rely on a single piece of evidence as the end of a genealogy investigation. Census records for example are often incorrect. A DNA test is just another piece of evidence that enters the record in our attempt to discover our ancestors. We have many cases of DNA results adding to our knowledge. There is one example of an adult male who abandoned his family, adopted a new surname and fathered a second family (mid 1800's). The living genealogist from this second family could find no record of this ancestors parents or siblings of course. A DNA test of descendents of both families revealed that they had matching DNA. With that information, the genealogy record was finally pieced together. There are many cases of unmarried women with children who take the maternal surname. If descendents of these children want to learn who their male ancestor was, DNA offers a very powerful method of aiding in that search.
                          There are many gaps in the paper trail. We accumulate circumstantial evidence, such as migration patterns, naming patterns, neighbors that moved together etc., and we often draw conclusions based on the preponderance of this evidence. I am eager to alter my ancestry if new evidence is found proving that the conclusion I have drawn based on circumstantial evidence are wrong. DNA is another piece of evidence that we can add to this record.
                          There are many cases of DNA leading to confirmation of relationships that were only suspected. There are also cases of DNA tests leading to the conclusion that an accepted genealogy based on the paper trail was incorrect.
                          If we are seeking the truth, we should not ignore
                          tools which will help us arrive at that truth.
                          Dennis West

                          Comment


                          • #14
                            John,
                            I am happy to say that the usefulness of these tests is not just wishful thinking. True the certainty of some of the matches can seem a big vague, but total mismatches of results tell you very clearly that two people aren't related .

                            I mentioned to you earlier the reaons why I was having my fathers Y-line tested * to determine whether our "Cone" family from Suffolk England was related to:
                            - Jewish Cohens (a theory my mother had for over 30 years),
                            - Scottish/Irish Cones
                            - German Cones,
                            - or whether my Suffolk Cones (along with others in England) constitutes a seperate origin of "Cone" altogether.

                            I have half óf my fathers results back, and can say with 100% certainty that my "Cone" family does not have a Jewish origin. My fathers results also don't match at all closely with Cones of an Irish/Scottish origin - so for now, it seems very unlikely that my "Cones" have any relationship with Scottish/Irish Cones.

                            We have now eliminated 2 of the 4 possible origins............

                            At present, my fathers results closely match a variant surname of the possible German origin. We are currently awaiting results of the next 13 markers to see if it is a match in an anthropological time frame (ie. a common ancestor in the last 2000 years) or a geneological time frame.

                            Sure, the test hasn't yet told me who my family is related to 100% beyond a doubt - but I know with certainty who my family isn't related to. That in itself is worth the cost to me.

                            How do I write that in my Family tree? - simple - instead of waffling on about the four possible origins of the name "cone", I can now write about just two possible origins. In time, further test results will refine that down even further.


                            Angela.

                            Comment


                            • #15
                              Hi John,

                              I searched your name in our database, and couldn't find. I don't know if you tested with any companies, or if you are part of a Surname Project, and as such has come to the conclusion that you stated in previous postings.
                              All I can say is that with over 18,000 tests performed, and more than 850 surname projects, we have enough facts to prove the usefulness of DNA testing for genealogy purposes. We have even more than that. We have cases that are worth being in the news, and the only reason they are not, is to protect the individuals privacy.
                              In any case, if you feel that you need more than this information and more than the reply from the Group Administrators that are in this forum, do a search for DNA and Genealogy or Genetic Genealogy at Google. You will find dozens, if not hundreds of pages from DNA projects with a lot of reading materials, many times written by people that are mathematicians, physicists, or have other high levels of education, where they - not FTDNA - make the case for the use of Genetic Genealogy.
                              Max Blankfeld
                              Vice-President and COO @ Family Tree DNA
                              A Gene by Gene Company

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