A double-cos-site vector containing a multiple cloning site flanked by T7 and T3 RNA polymerase promoters

A double-cos-site cosmid vector, c2XMCS, contains a multiple cloning site (MCS) with fifteen restriction sites flanked by phage T7 and T3 RNA polymerase promoters. The two cos sites in the cosmid vector enable the construction of cosmid libraries from unfractionated partial digests of genomic DNA. This simple construct combines the efficiency of a double-cos-site cosmid with the versatility provided by the MCS from pBluescript.