I am doing the subcloning and just double digested the plasmid (pET-21a) with RE of XhoI and NdeI (both from NEB).
However, after double digestion (I did it for O/N), the DNA gel showed there was a band on the very top, as if it almost didn't move at all from the loading well. I did the twice and each time saw the same thing. I am just wondering is there anybody else have seen this before? Can any one tell me what this band is on earth?
By the way, using the same way to double digest my pET-28C vector and there is no such a band.
Any suggestion will be deeply appreciated!
Edited by huangc4, 04 February 2009 - 01:51 PM.