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Is it possible that the undigested version of this plasmid will be above the lin - (Oct/04/2013 )

I have plasmid called pUC4K and I did restriction digestions a few times with a few different estriction enzymes. The patterns of the bands I got on an agarose gel were correct and i could confirm that this really is pUC4K plasmid. However, I loaded the uncut version of this plasmid the linearized version of this plasmid and the uncut version of this plasmid was above the linearized version of this plasmid. I know that usually the uncut DNA appear below the linear DNA, but I don't know why this uncut one was above the linear one. Is it possible? or am I doing something wrong?


This is normal. Uncut circular plasmid can assume a number of forms, some of which run faster, and some slower, than the linear form of the plasmid.