Protocol Online logo
Top : New Forum Archives (2009-): : Molecular Cloning

What is the difference between cotransformation and (single transformation to th - What is the difference between cotransformation and single transforma (Mar/16/2009 )

Every body Hi ,
Actually my experiment was cotransformation for Top10 , but my Professor told me i have to prepare competent cell harboring one plasmid then i have to do single transformation, here i got much more clones in plate than in cotransformation .
Can anybody tell me what is the scientific reason for the difference in enumerated clones betwwen them ?
Thank you


I've never dun cotransformation but as I understand it, in one reaction of transformation you put 2 plasmids.
From my experience with transfections, the number of cells that accept both plasmids is small.
On the other hand, if you do 2 separate transformations, the yield is higher.


I had absolutly no problems with cotransformation, you maybe should take a little bit more plasmid DNA. The good thing in first putting in one plasmid and then transforming these cells with another plasmid might be that you don't have to check for both plasmids later if you don't have different selection markers. I needed the cells completely fresh cotransformed because I worked with a bacterial two hybrid system - therefore I can say that interaction activity decreases a lot when you transform them in two steps.

Hope this helps! :)