contaminated Taq

[Joseph Michael Bay]

brett at BORCIM.WUSTL.EDU (brett) writes:

>>Merely that I shudder when I recall the experiences of some students I have
>>had doing PCR...
>>undergrads rather than postgrads.

>Sounds like you spend more time reading newsgroups than training
>students.  Shame on you if an undergrad can't perform a PCR, not
>to mention your attitude.

Touchy.  Everyone makes mistakes, and a lot of them make mistakes
in PCR the first time (or first few times).  That's not an insult;
it's just a fact.

As for contaminated Taq, keep in mind that there are a half dozen other
things in common to all your reactions - any reagents, any tools, etc.
Is everything really sterile and DNA-free?  Short DNA sequences are prone
to aerosolization.  In fact, Hoffmann-la Roche suggest that you do the
actual reactions in a place nowhere near the place where you're analyzing
the DNA.  Labs that do lots of PCR (eg, for medical diagnostics) are 
very vulnerable to getting false positives due to the sheer amount of
"positive control" DNA floating around.




-- 
Joe Bay                        Leland Stanford Junior University
"Bother,"  said Pooh,  as he looked upon the visage of  Cthulhu.
Putting  the  "harm"  in  "Molecular  Pharmacology"  since  1998
Fairness   and   Accuracy   In   Reporting- http://www.fair.org/