UV damage and cloning, was Re: aberrant DNA migration on an agarose gel

Rob Jordan rjordan at u.washington.edu
Tue Aug 1 18:43:35 EST 2000

> An alternative (and I think easier) approach is to go ahead and run the
> with EtBr and then make sure to visualize with a UV source that won't
> damage the DNA, e.g. a long-wave hand held UV lamp is what I use.  I've
> used this approach for years without any problems cloning.  Of course I'm
> still careful to try to minimize the UV exposure, but I think the
> EtBr-stained DNA can still take a lot of long wave UV without damage.

What I've done (after someone suggested it here) is to put 1mmol/L cytidine
in the running and staining buffer. I don't do that much cloning so I don't
know how much it actually helps in my case, but it's very simple. Here's the

Grundemann and Schomig, Protection of DNA during preparative agarose gel
electrophoresis against damage induced by ultraviolet light. Biotechniques
21:989-903 (November 1996).


Robert Jordan
Radiation Biology Laboratory
University of Washington Medical Center
Box 356069
Seattle, WA 98105

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