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Ancestry V FTDNA

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  • Ancestry V FTDNA

    I have four matches at Ancestry and One match at FTDNA. One of my matches from Ancestry decided to test at FTDNA and they have a MRCA of 10 Generation or 250 years at Ancestry. This match again match me at FTDNA but has a Genetic Distance of only one. I know this is close but it seem to be a big difference between the two, so why the big difference?

    I'm not asking for votes on which company is the better company so please no comments on who's the better choice I already know.

  • #2
    It is impossible to answer your question without more information. How many markers were being compared at ancestry? What was the genetic difference at ancestry? How many markers are being compared at FTDNA?

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    • #3
      GD and MRCA are separate items. The first is a difference in values, the second a timeframe prediction. MRCA from ancestry is to a 50% or 90% or some other percentage, rather than the per-generation chart provided by FTDNA.

      Some of the ancestry markers aren't tested in the standard FTDNA tests until Y111 (although you can order them separately). However, based on the information provided, these numbers do not seem unreasonable to me.

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      • #4
        Thanks for the replies

        Both of us did 46 markers at Ancestry and 67 at FTDNA

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        • #5
          The TMRCA (time to most recent ancestor) calculator at Ancestry seems buggy and inaccurate to me. A match at 66/67 should be quite recent, probably within 200 years.

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          • #6
            The more markers tested should give the more accurate GUESS of TMRCA. Of course these calculations are based on AVERAGE mutation rates. Are your rates average?

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            • #7
              Understanding the Genetic Distance has "1-2 Tightly Related" and the Interpretation say's "Few people achieve this close level of a match. All confidence levels are well within the time frame that surnames were adopted in Western Europe."

              I was thinking it maybe a mistake on FTDNA part but they do have two lab Tech's reviewing the results so one is checking the others interpretation of the results. So the odds are the interpretation is correct.

              I don't like this Genetic Distance stuff its hard to understand and I can't find anything that helps in understanding it. If you have matches that you can't see their results what are you suppose to do? The one thing Ancestry does that FTDNA doesn't is show you your matches results so you can compare with them.

              Joining a group is no good if you don't share the same surname as your matches and sponsoring someone means I have to find someone who looks like a possible match and than sponsor them. Than your matches may not be in a group.

              It would be helpful if FTDNA would do as Ancestry when it come to your matches.

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              • #8
                Edward, I agree, although I have had good luck looking in ysearch.org. If people have uploaded their values, you can see them all there. That said, it seems like matches who have made themselves available should also have their values available for viewing in FTDNA.

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                • #9
                  Jim at Ancestry we miss on three markers, me than him 12/11 461,13/14 464a, 14/15 464b. FTDNA has us as a Genetic Distance of only 1.

                  sjadelson I had forgot about Y-search but have used it before. The only problem with Y-search is the phishing thats going on there. Thats a problem that will keep people from posting their results there. Y-search is still a good tool but until the phishing problems is dealt with FTDNA should make it so you can see your matches on FTDNA site only.

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                  • #10
                    Originally posted by EdwardRHill View Post
                    Jim at Ancestry we miss on three markers, me than him 12/11 461,13/14 464a, 14/15 464b. FTDNA has us as a Genetic Distance of only 1.
                    I also find calculating Genetic Distance to be confusing. At a overly simplified explanation it is the sum of all of the differences, "except" and that is where I get lost. I do know that markers with multiple peaks is one of those areas.

                    Since you didn't say how you differ at FTDNA I can't comment on their value. You might send them an e-mail asking that they explain how they calculated the value.

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                    • #11
                      Comparing Ancestry to FTDNA results

                      I have a first cousin that I have known all of my life and unless there was something going on we know nothing about, I am positive his dad and my dad were brothers. He tested a while ago on Ancestry and I did YDNA67 here. I uploaded my info to Ancestry and found we have a GD of 6. DYS 442 for me per FTDNA is 12 and for my cousin on Ancestry was 17? Is this possible? How do I make sense of this?

                      Thanks

                      Bruce

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                      • #12
                        Thanks Jim I think I'll wait until my new match gets a chance to upload to y-search. I'm not looking to become Genetices and just wish FTDNA could simplify some of this stuff instead of trying to make us all Junior Genetices.

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                        • #13
                          Yeah--the GD calc rules for multicopy locations like 464a,b are weird.

                          FTDNA's method for counting GD at 464a,b ususally goes like: "Allright, man #1 has 13,14 and man #2 has 14, 15. Therefore I deem you have GD of 1--a single 2-step mutation between man#1's 13 and man#2's 15."

                          I don't know whether Ancestry observes the same multicopy protocol. I have seem some utilities (like Sorenson) that don't, and simply consider them to be 2 distinct 1-step mutations.

                          However, I don't think either of these scenarios alone would get you to a GD of 4 at Ancestry AND GD of 1 at FTDNA. The difference could be that FTDNA doesn't test the same range of markers that Ancestry does. I can't recall where 461 falls in the FTDNA sequence or whether they test for it even.

                          Also, it is just possible that one lab screwed up on 464a,b. Those mutlicopy location markers are the easiest to screw up in testing, because some methods require you to estimate their lengths relative to one another. It's a stochatic process, and some error is bound to happen when a high volume of tests are performed. Statistically it seems to be at a rate of less than 1 half percent, but it does happen.

                          Originally posted by Jim Barrett View Post
                          I also find calculating Genetic Distance to be confusing. At a overly simplified explanation it is the sum of all of the differences, "except" and that is where I get lost. I do know that markers with multiple peaks is one of those areas.

                          Since you didn't say how you differ at FTDNA I can't comment on their value. You might send them an e-mail asking that they explain how they calculated the value.

                          Comment


                          • #14
                            Originally posted by BruceG View Post
                            I have a first cousin that I have known all of my life and unless there was something going on we know nothing about, I am positive his dad and my dad were brothers. He tested a while ago on Ancestry and I did YDNA67 here. I uploaded my info to Ancestry and found we have a GD of 6. DYS 442 for me per FTDNA is 12 and for my cousin on Ancestry was 17? Is this possible? How do I make sense of this?

                            Thanks

                            Bruce
                            Some companies count the STRs differently, so when transferring results from one to the other you need to add 1 here, subtract 2 over there, etc. When you entered your results on Ancestry, did you make sure to set the pull-down menu to FTDNA? Otherwise the markers Ancestry and FTDNA count differently won't be correct in the database. According to this handy table, DYS442 at FTDNA is +5 compared to Ancestry.

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                            • #15
                              Thanks for the information. I will adjust it. I did not see the pull down menu you are referring to, I will check it out.

                              Bruce

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