Posted 23 July 2013 - 12:40 PM
I am using Blue/White screening to check if my plasmid tranformation into DH5alpha worked. As expected - I received all blue and all whtie colonies for one of my transformations. In my other transformation though, I got all blue colonies and white colonies with a tint of blue in the middle. I did store my plates ON 4C before picking colonies. The initial incubation period was for 16 hours at 37C. 100ul of 50ug/mL Xgal was used directily in the transformation products (not the LB agar + Ampicillin plates). 50ul of 20% IPTG was also added to the transformation products before plating.
Any idea why I am getting a blue color in the middle of ALL my white colonies for one of the inserts? As stated - there are solid blue colonies on those plates as well.