Extra band following gel purification?

[Matt Huentelman]

After doing a double digestion with BamH1 and Mlu1, I gel purified 
(Quiagen)  a product of approximately 2.6kb, however when I ran it on 
a gel following purification I saw an additional band that was at a higher 
concentration but a smaller mass.  Does anyone know what this band 
could be and can I still use my purification product for cloning?
Thanks.
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