Lambda DNA migration in agarose gels?

Dr. Duncan Clark Duncan at
Thu Oct 22 09:32:27 EST 1998

In article <362F1BF9.3E4F9416 at>, Jens Mollerup
<jmollerup at> writes
>We have purified lambda ZAP ll DNA with a size of 40kb. Surpricingly,
>when runned on an 0.6% agarose gel this fragment goes as a 20kb band?
>After one cut with a restriction enzyme two bands at approx 20kb
>appears. Does anyone have an explanation for these observations?
>Thanks in advance

Run very slowly overnight without EtBr and post stain. To resolve 40kb
from 20kb you will need say a 20cm long gel and maybe 0.4% agarose.


The problem with being on the cutting edge is that you occasionally get 
sliced from time to time....

Duncan Clark
DNAmp Ltd.
Tel: +44(0)1252376288
FAX: +44(0)8701640382

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