Plasmid dna size
Posted 01 December 2017 - 04:10 AM
Colony pcr was done to select the positive transformants. after growing and plasmid prep of the selected transformant, the plasmid dna was run on gel. My expected product size would be more than 10k. However, apart on a band at more than 10 kb, a band was also obtained at around 1.5 kb. I couldn?t find an explanation towards the 1.5 kb product. I appreciate help here for possible explanation towards such result. Am I getting the correct product? Thank you.
Posted 01 December 2017 - 07:06 AM
There are a couple of things that could be going wrong -
It could be that you are getting fragmentation of the plasmid during isolation, but this would come out as a smear usually.
It might be that the bacterial strain you are using has more than one plasmid in it. Try digesting the plasmid prep with a couple of RE's (usually you would use the ones you used in the cloning) to see if this band disappears.
Posted 02 December 2017 - 03:37 AM