EtBr and heat denatured DNA

Mark Spanevello deletethismark at
Tue Feb 24 15:57:39 EST 1998


EtBr is an intercalating agent, which means that it "binds" to the DNA
by inserting itself between the two strands.  EtBr will not fluoresce
with ssDNA, it requires dsDNA

Frederik Boernke wrote:

> Hi all,
> lately I prepared carrier DNA for transforming yeast using the Gietz
> protocol. I sonicated the solution as long as the average fragment
> size
> ranges around 7 kb which was judged from an agarose gel. I than heat
> denatured the DNA and quickly cooled on ice in order to keep it in a
> single stranded manner and subsequently checked it again on a gel. But
> this time all the DNA, except for some low MW smear, seemed to have
> disappeared. Does EtBr not properly stain ssDNA or did I something
> wrong
> in principle?
> Cheers
> Ricky
> ******************************************************************
> Frederik Boernke
> Research Group of  Molecular Plant Physiologie
> Institute for Plant Genetics and Crop Plant Research (IPK)
> Corrensstr. 3
> 06466 Gatersleben
> Tel.  039482 -5 321
> Fax. 039482 -5 515
> e-mail: boernke at

Mark Spanevello

(to reply, remove "deletethis" from email address)

Faculty of Science and Technology
Griffith Univeristy
Nathan Campus
Nathan, Qld, Australia,  4111

Ph:  (07) 3875-7622
Fax: (07) 3875-7656

email : M.Spanevello at
        mark at


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