# FAQ: What are the additional bands I see on the gel?

The predominant form of DNA produced should be supercoiled, which typically has a faster mobility during agarose gel electrophoresis than linear plasmid. In addition to these two forms, an open, single-stranded form can sometimes be observed at lower molecular weights than the supercoiled form as a result of excessive alkaline lysis and denaturing of the plasmid. Higher molecular weight forms of the plasmid can also sometimes be seen, including a nicked or relaxed form, referred to as open circular, which typically migrates higher than the linear form. Concatamers or multimers of plasmid are sometimes also seen at even higher molecular weights. The relative positions of these bands may differ in TAE vs. TBE buffers.