Ethidium Bromide

Paul N Hengen pnh at
Fri Jun 11 12:08:37 EST 1993

In article <nash.176.0 at>
 nash at (John Nash) writes:

>What I do remember was an experiment we did in 2nd year biochem, wa-a-ay 
>back in 197-umph!.  We looked at the ability of ethidium bromide to: a) 
>cause petite mutations in yeast, and b) revert a tyr mutation to wild type
>(also in yeast).  It did the former very well, but not the latter at all.  
>On the other hand, EMS did b) very well indeed.  So, if your DNA is not 
>naked, maybe you don't have to worry as much????

Maybe if you're a budding yeast :-) The major concern I have is that people
will read this as "It's okay to dump it, it's harmless". John, you and I
both know that some labs store large quantities of very concentrated EtBr
and that some people in the lab will mix this with other chemicals that
may be toxic or contribute to the human toxicity of it. Then years later
decide it has sat around long enough and should be mixed with bleach or
dumped without trying to inactivate it, all the while without knowing what
other stuff is in there as well. Please don't dump it all down the sink just
yet. I don't want to eat fishy fish.

Paul N. Hengen
National Cancer Institute
Frederick Cancer Research and Development Center
Frederick, Maryland 21702-1201 USA

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