2. Adaptor Molecule- During a restriction digestion of chimeric DNA, in few cases the restriction enzyme cuts the linker molecule or foreign DNA. This can be avoided by choosing different restriction enzymes but in some cases

Figure 13.1: An Over-view of different steps involved in cloning.

it is not possible. In such conditions, an adopter molecule can be added. Adaptor molecules are 8-10 nucleotide long double stranded molecule with flanking DNA sequence to provide cohesive ends (Figure 13.3). These cohesive ends have free hydroxyl group to facilite efficient ligation to the vector. Chimeric DNA containing adaptor molecule is incubated with BamH-I digested vector in the presence of DNA ligase to get circular clone (Figure 13.3).