Replicating start site 2. Cloning vectors - Plasmids, Phages, Cosmids Plasmids may be under stringent control or relaxed control. Ampicillin resistant gene 2. Gene for alpha polypeptide of beta-galactosidase 3. Cloning sites located inside the gene for the alpha polypeptide of beta-galactosidase.
Blue colonies result.
If the plasmid is not transferred - no colonies form. If foreign DNA is inserted into the pUC plasmid it goes inside the gene for the alpha polypeptide of beta-galactosidase. Therefore, white colonies result. Phage vectors can incorporate up to 16 kb of foreign DnA. Charon - Phage vector with missing genome. YACS - Yeast artificial chromosome.