Archiver > GENEALOGY-DNA > 2005-09 > 1127933784

From: Thomas Krahn <>
Subject: Re: [DNA] Re: Another set of extended DYS464, DYF385S1, DYF399S1results
Date: Wed, 28 Sep 2005 20:56:24 +0200
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In-Reply-To: <>

Dear Ed,

Errors simply can happen. I must confess, that in my results, there have
also been (a very few) errors because of transcription or because of
misinterpretation. No lab can be error-free. From the GeDNAP round robin
test of more than 150 worldwide labs each year we know, that the error
rate of conventional and forensic labs is far below 1%.

When we talk about DYS464 (also YCAII, DYS413, or even DYF399S1) we must
be aware, that theese markers are very difficult to interpret. Customers
should be aware, that if they have a mismatch in those markers, it is
really worth having a closer look at them and not simply take the
results for granted. The lab that does the first analysis doesn't expect
an odd, or difficult result, but if the context doesn't match, it is
always recommendable to ask back to the laboratory and check the
electropherogram a second time.

One of the main reasons why I have developed DYS464X is the fact that
peak heights at DYS464 are difficult to interpret. With DYS464X it is
sometimes possible to get a better insight into the cluster of DYS464
peaks, at least for members of the R1b club.



> I am a complete novice but if different labs get different results on the
>same person.. how often does this happen? This would seem to be a serious
>problem if folks are paying for tests that cost a pretty good chunk of money and
>then may receive a false or partially inaccurate 12,25,37, 43 or whatever
>marker result. If the labs are over booked, does that make the ones testing the
>samples work too fast and not have proper controls over results? Too much
>pressure? Do some labs have better testing methods and history of accuracy? Are
>samples prone to some inaccuracy depending on how and when you take them and mail
>them in and handle them? If so, what approximate percent of error exists in
>the total folks that have been tested at the labs?
> Anyway, I think EACH person tested deserves to get as accurate result as
>is possible at ANY lab for their payment and for their family line. I hope all
>of us would agree on that principle. The question is what is the ACTUAL
>accuracy of reporting? I know the labs must have some data feedback on retests done
>and reassignment of a persons marker results. In most industries there is
>some amount of error. I imagine it is hard to find a perfect quality company. So
>I hope if/when something does not "look right" or inconclusive results are
>seen that the time will be taken to get it right. I also know that frustrates
>some folks being tested because of extra time and concern. If I receievd
>different results on similar tests at two different labs I sure would be asking why.
> Some of us may have a genealogy group with only one person in the
>surname available to be tested (the line is full of descendants, but the surname
>males are few now to be found or not know where they are living or if living
>will not agree to be tested), so whatever their results are is what the whole
>research surname group is going by for early ancestry etc...
> I know that labs indicate they do alternate/second vial tests and
>further tests if they see inconclusive results or even send out a new kit for a
>complete new sample. Still if we see different results on the same person by two
>different labs, that is a a problem as I see it. Maybe I am misinterpreting
>what is being said in this. Maybe the method of rounding could effect the
>results. I am not up on this part but it seems to me that if detail breakdown test
>done accurately showed a 15.3 and it is agreed that this is the correct
>result/nomenclature and most accurate way to show the result shouldn't this be the
>standard the labs use? If the result for a critical marker was shown as 15 or 16
>or 17 instead of 15.3 couldn't that effect the meaning of the persons
>haplotype or halpogroup?

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