Synthesis of Genes form Three Duplex Fragments - The three fragments 'A', 'B' and' 'C' were joined to give complete gene in each of the two following ways;

(i) In one scheme, 'A' was joined to 'B' taking advantage of the overlap in residues 17-20; 'C' was then added, with the overlap in the region 46-50 residues. The complete double stranded DNA with 77 base pairs representing the gene was thus ready.

(ii) In the other scheme, B' was first added to 'C' and to this 'A' was added in the end to obtain the complete gene.

This gene, which was synthesized in 1970, was hopefully used for subsequent work, since this gene could replicate and make its own copies.