We define linker sequences as TAILs (Tail Linkers) and IDOLs (Inter Domain Linkers). The TAILs are all sequences at the two terminals external to the first and last domain in the protein. Each protein provides two entries. The IDOL is a collection of all interdomain sequences (excluding TAIL). Protein TAIL's length was defined as the mean of the two tail segments. In the same way, IDOL length was defined as the mean of the lengths of the inter domains linkers.