EtBr ussage

nishir at nishir at
Tue Jun 22 18:21:49 EST 1993

In article <1993Jun18.152949.1 at> brennanp at writes:
>On EtBr,
>I once heard an interesting suggestion that instead of soaking
>the gel in EtBr to add small amount of EtBr soln to the samples
>before running the gel.  It still allows visualation but does
>not require the large amts of EtBr reqd for soaking gels.
>I have never used it myself but it sounded neat, maybe someone
>else knows more details
>Paul Brennan, Trinity College, Dublin, Ireland
We have tried this for both DNA and RNA samples.  It works with RNA; not with
DNA.  The EtBr migrates away from the DNA so you get an "extra" band that is a
glob of EtBr migrating in the opposite direction of the DNA.  As long as you
know what this is, it's OK for simple DNA samples that you're trying to
visualize (eg., plasmid that has been cut once or twice). 

Rae Nishi
Cell Biology & Anatomy
Portland OR

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