Plasmid isolation again - Isolation from multiple colony? (Aug/02/2002 )

Hi everyone! It is a basic that one has to take a single colony for plasmid isolation. But why? What is going to happen if to mix several colonies together? By doing this we just reduce the risk of getting plasmid with rearrangements/spontaneous mutations. Am I right?

The DNA you would isolate from several colonies may be of mixed origin. If you plan to do digestion or PCR to an expected DNA segment, you may get inconclusive results though you may have the correct DNA some where. In my opinion, taking single colony at a time will give  a better result eventually