plasmid - (Aug/07/2007 )
i saw many bands after checking the the isolated plasmid with the gene of interest in an agarose gel. the plasmids were isolated from a culture of ecoli. is it possible to see chromosomal dna in the agarose gel? or are those bands signify plasmids that may be linear, coiled, supercoiled ? thanks so much for info
Hi Rina77,
what sizes were the bands you got? And how many bands did you get?
Three bands indeed should be the circular, linear and supercoiled plasmid.
Greetings,
Chakchel
hi chakel, thanks thanks. there were more than three bands unfortunately and the sizes range from 4k-5k with some bands less than 1kb. what is the possible explanation for that?
thanks again
hmmm... maybe it can be genomic DNA then...
There was once a topic about that problem, maybe it will help you?
http://www.protocol-online.org/forums/inde...;hl=genomic+dna
Greetings,
Chakchel
Hi
I have had this problem recently also when i cloned a purified PCR product into a basic TOPO 1 plasmid & reran it through the PCR (SYBR green)
I kept getting extra bands & peaks
It turned out my primers shared limited homology to some of the promoter regions on the plasmid
Have you checked your sequence to see if it has any homology with the plasmid sequence?