DNA-construct assembly pathway. The vector M13mp18 (7250 bp) is used to produce a DNA building unit of approximately 5 μm length with an elongated single stranded sticky end at both sides. 1 - 4: Formation of single stranded adapter oligonucleotides. 6, 7: Ligation of adapter elements to form two DNA-constructs that are capable to bind site specific. 8: Hybridization will occur spontaneously and will result in the long DNA-construct.