In molecular cloning, Blue-white screening is used for

The blue-white screen is a screening technique that allows for the rapid and convenient detection of recombinant bacteria in vector-based molecular cloning experiments. DNA of interest is ligated into a vector.The vector is then inseed into a competent host cellble for transformation, which are then grown in the presence of X-gal.Cells transformed with vectors containing recombinant DNA will produce white colonies; cells transformed with non-recombinant plasmids (i.e. only the vector) grow into blue colonies.This method of screening is usually performed using a suitable bacterial strain, but other organisms such as yeast may also be used.DM VASUDEVAN 7th edition pg no 626 627