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Wow! Skewed results by competing companies?

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  • #16
    I remember the Genographic Project kit said to scrape, but not hard enough for blood to flow. It never mentioned the conseqences. My #1 sample did contain a small amount of my blood, then I read the warning between samples. My second scraping was bloodless.

    My deep SNP test was late a couple of days because they had some difficulties with the first go at it. It may have been the blood or the food warning that I ignored. I had eaten an arrowroot cookie a few minutes before taking the swab to my mouth.

    The greatest problem I have with this is that uploading to Y-search is done by complete rookies in these web sites. I was enthusiastic about the latest names of sub-clades and probably mistakenly put mine down as E3b1a rather than E3b1. Afterward I forgot my password and haven't gotten an automatic response to "forgot your password" after lots of tries.

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    • #17
      I scraped so strongly so my first sample got quite a lot of blood in it. The second got less blood in it, but anyhow some amount. But I was careful with not having eaten anything before scraping. My 12 markers' results arrived quite normally, and so did also my 25 markers' result, only SNP results were a bit delayed (three weeks I think), but I don't think the blood had any influence on that.

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      • #18
        Originally posted by Arch Yeomans
        Most errors from the lab are actually the fault of the customer.
        This is a very sweeping statement to make without strong specific evidence. Do you work at FTDNA?

        My own opinion is that your statement is probably true of new customer orders, but not upgrades. If a sample has successfully produced results in the past, the customer probably swabbed correctly. There are many other reasons that a lab test can fail besides customer error.

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        • #19
          Odds are higher for consumer caused cross contamination

          Originally posted by lgmayka
          This is a very sweeping statement to make without strong specific evidence. Do you work at FTDNA?

          My own opinion is that your statement is probably true of new customer orders, but not upgrades. If a sample has successfully produced results in the past, the customer probably swabbed correctly. There are many other reasons that a lab test can fail besides customer error.
          Dealing with forensic evidence we all learn about how easily things are cross contaminated. The odds are higher for an uneducated or unaware customer to incorrectly conduct the cheek swab. The enzymes used to "break down" the DNA are usually done in a specific type of solution to be used in the DNA analyzer.

          No I don't work for Family Tree DNA, I'm a certified evil mad scientist .

          Yes labs can cause errors too, but experienced lab techs are most likely going to handle the samples more carefully than some person who made no effort to read the instructions or simply ignored them. Basically in an ideal world there would be no direct handling of the swabs by the customer as well the lab tech. Having a trained med tech draw blood into a sealed vial would be the most ideal way to take samples as well safely handle them.

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          • #20
            Originally posted by SaintManx
            After banging my head against the proverbial wall with regards to why I am so far off in genetic difference from family members I noticed that a person in my group has tested himself twice. Not only that, they were with competing companies (Genographic Project and FTDNA), but he was a genetic difference of three off with himself!!! How is this possible?

            His Y search numbers are 7ET93 and R4UXJ. The contact info is the same as well as the Immigrant Ancestor. I have sent an email to him but this skews the results of our project significantly and opens the door to several other questions.

            Can anyone shed some light on this?

            Cheers.

            Kit # 72248
            Y Search 9epze
            The Genographic Project and FTDNA report 389i and 389ii, click here

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            • #21
              If drawing blood was the original way of extracting dna why would a little blood in the swab contaminate a sample?

              scot

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              • #22
                Originally posted by lgmayka
                If a sample has successfully produced results in the past, the customer probably swabbed correctly.
                This statement is not true or, at the very least, is meaningless.

                A scrape that is adequate to generate reliable results on one test is not necessarily adequate to generate a reliable result on a different test.

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                • #23
                  Originally posted by scotdna
                  If drawing blood was the original way of extracting dna why would a little blood in the swab contaminate a sample?
                  When blood is drawn for use in DNA testing, it is usually processed quickly in order to isolate the DNA from other material (red blood cells, protein debris, etc). The isolation steps for salival samples are different from the steps for blood samples. If there is blood in the saliva it acts as an inhibitor to the PCR process.

                  Compare these commerical products, one designed for isolating DNA from blood samples and one for isolating DNA from oral samples:

                  http://www.agencourt.com/products/sp...gents/genfind/
                  http://www.agencourt.com/products/sp...gents/orapure/

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                  • #24
                    Originally posted by vineviz
                    A scrape that is adequate to generate reliable results on one test is not necessarily adequate to generate a reliable result on a different test.
                    False. It is true that tests vary in their sensitivity, but that is essentially a property of the test, not the fault of the customer.

                    Let us keep in mind that FTDNA does not blame the customer in such situations. FTDNA realizes that its tests are somewhat temperamental (to say the least!) and goes to various lengths to compensate for that. Indeed, FTDNA admits that its 37-to-67 tests are acting extremely temperamental right now, and so many results will be a month or more late. FTDNA is profusely apologizing for the situation.

                    But again, FTDNA is not blaming customers for this, and I find it extremely irritating for intrusive third-party gadflies to do so. If these gadflies think they are "defending FTDNA's honor," they are very much mistaken. Indeed, they are much more likely to unfairly incite anger against FTDNA, unfortunately. Loser companies occasionally try a Blame The Customer strategy--and promptly go out of business.
                    Last edited by lgmayka; 14 December 2006, 09:06 PM.

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                    • #25
                      I, for one, am happy about FTDNA's policy of testing, retesting, and re-retesting if need be to get quality-assured results.

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                      • #26
                        Originally posted by lgmayka
                        It is true that tests vary in their sensitivity, but that is essentially a property of the test, not the fault of the customer.
                        Fault and blame have nothing to do with anything we are discussing. Some tests require less donor DNA than other tests: that is an incontrovertible fact. Thus, it is incorrect to assert the following:

                        Originally posted by lgmayka
                        If a sample has successfully produced results in the past, the customer probably swabbed correctly.
                        No matter how many times such a position is asserted, it will always be incorrect. And frankly I marvel that folks who should know better continually fail to grasp the point.

                        The entire premise of the assertion is false: there is no "correct" way to swab, at least not in the sense that using a certain technique (even the prescribed one) will always result in enough donor DNA for every conceivable test.

                        The customer's responsibility is to make their best effort at swabbing effectively, and the lab's responsibility is to make their best effort at isolating and amplifying the results. Neither the customer nor the lab are in a position to guarantee success.

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                        • #27
                          Originally posted by Andrew M
                          I, for one, am happy about FTDNA's policy of testing, retesting, and re-retesting if need be to get quality-assured results.
                          Yes, we should all be relieved that FTDNA has the integrity not to report unsure results. I hope that none of us want to see iffy results that could lead both customers and researchers on wild goose chases. Individual customers actually have much greater need for accuracy than academic research projects do.

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                          • #28
                            Originally posted by vineviz
                            When blood is drawn for use in DNA testing, it is usually processed quickly in order to isolate the DNA from other material (red blood cells, protein debris, etc). The isolation steps for salival samples are different from the steps for blood samples. If there is blood in the saliva it acts as an inhibitor to the PCR process.

                            Compare these commerical products, one designed for isolating DNA from blood samples and one for isolating DNA from oral samples:

                            http://www.agencourt.com/products/sp...gents/genfind/
                            http://www.agencourt.com/products/sp...gents/orapure/
                            Thanks, Vineviz.

                            It's always nice getting a response that addresses the issue without veering off into left field.

                            Scot

                            Comment


                            • #29
                              Originally posted by lgmayka
                              This is a very sweeping statement to make without strong specific evidence. Do you work at FTDNA?

                              My own opinion is that your statement is probably true of new customer orders, but not upgrades. If a sample has successfully produced results in the past, the customer probably swabbed correctly. There are many other reasons that a lab test can fail besides customer error.

                              My first sample produced on time results for 1st and 3rd panel Ystr, and deepSnp. It failed 3 times on the second panel Y. This doesn't prove or disprove anything, but it doesn't feel like a successful swabbing.

                              Scot

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