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DNA Sample

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  • DNA Sample

    I'm not sure where to put this question so I may put it in two forums. Does anyone know how many tests can be done on a DNA sample? On one of my kits I've had the FF, Y 37 and the Y111.

  • #2
    It would depend upon the quality of the sample, but it seems to me that it would be hard to predict. I know that some tests use up more of the DNA sample than others, but so far haven't been able to locate any articles describing the different amounts needed. It's all moot if, for example, one test fails and they need to try again; that will use more of the sample. And you don't know if that will happen or not.

    For examples, of two of the kits I administer for older males, for which I have attempted to have extended testing done, here is my experience:

    Tester #1 had done a Geno 2.0 test (late 2012), then "transferred" the DNA sample to FTDNA (FTDNA was processing Geno 2.0 tests at that time, and I believe was already storing Geno 2 vials in the same building as the FTDNA vials).
    • A Y-DNA 67 marker test was done soon after the Geno 2.0 transfer
    • mtDNA FullSequence, and
    • one SNP test (both of these latter two in early-mid 2013)
    At that point, after four different tests (including the autosomal Geno 2.0), I was concerned there would not be enough DNA left to use for further tests (FTDNA had not expressed a need), so in mid-2013 I requested extra vials be sent. These two extra vials were used by #1 and sent back to FTDNA. After that, the following tests were done for #1's kit:
    • upgrade to Y-111 (late 2013)
    • SNP pack (early 2015)
    • Big Y (late 2015)
    • upgrade to Big Y 500 (mid 2018)
    I don't know if FTDNA used the extra vials of #1 for the later tests, but would think so for the original Big Y, or the Big Y 500 upgrade). At almost seven years old, I'm not sure if any remaining sample of #1 is viable. For Family Finder for #1, the FTDNA sample was not used: instead, his file from 23andMe v. 3 results was transferred in early 2013.

    Tester #2 had these tests done directly from an FTDNA sample:
    • Family Finder + Y-67 (both in early 2015)
    • Upgrade to Y-111 (late 2016)
    • An attempt to do the Big Y also (right after the Y-111) was unsuccessful, due to insufficient sample. #2 passed away before he could use a replacement kit.
    I did not attempt a mtDNAFullSequence test on #2, as that haplogroup had been determined through testing another relative in the same mtDNA line.

    As I did not assist or witness #2 in swabbing (but instead relied on relatives who lived near him to help him with using the swabs), I believe that either the swabbing for #2 was not performed correctly, or he provided a poor sample for some other reason. In retrospect, I should have ordered the Big Y instead of the Y-111 for #2 (at that time, he had only one STR match up to Y-37, and has only received one other match up to Y-111 just a few months ago - a total of two STR matches continuing above the 12 marker level). But, there's no sense crying over spilled milk.

    I've read that the Big Y 700 is best done from a fresh sample (vial), so if previous testing has used up the first original vial and some of the second (and/or perhaps it is a few years old), FTDNA may send a replacement kit to do the Big Y 700, should you decide to have that test done.

    The moral of the story is: request, use, and submit extra vials so you do NOT have my situation with #2 - particularly if the person tested is elderly or in poor health. See if they will send you three vials, vs. the two they sent me for both #1 and #2.


    • #3
      For my father I have done family finder, ydna 67, ydna 111 upgrade, ftdna ran backbone test on ydna, mtdna plus and a had a single ydna snp test done.

      all within two years of original sample submission.

      dna degrades over time so the older the sample it could have issues with test which require very few no calls in results

      Also for my father, at the time ftdna collected an extra vial to what they do now. Believe he submitted 3 samples
      Last edited by prairielad; 1 December 2019, 04:23 PM.


      • #4
        If questioning quality of sample for a ydna test it may be best to find another tester who carries the same ydna as original tester


        • #5
          Thanks for the replies. I just ordered the Y700 for a 3rd cousin's kit I administer. His sample is not very old, March of this year. Also, his test results from the three tests came back very quickly so I'm thinking he submitted a good sample. I'm just really hoping his remaining sample is adequate. It took me years to find this 3rd cousin (male) to take the Y test and now he seems to have dropped off the face of the earth so if another sample is needed I'm afraid all is lost plus my money