a product complementary to oligonucleotides 1 2 3 these cycles of melting annealing and extension are repeated until full length polynucleotide is formed the number of cycles should be equal or more than the number of oligos on microarray device after formation the final target polynucleotide molecule is amplified by a pcr process with two primers complementary to the ends of this molecule to the desirable amounts in a second embodiment a plurality of oligonucleotides that together comprise with overlapping regions the target polynucleotide sequence are synthesized on a microarray device or can be synthesized on beads as a solid substrate wherein each oligonucleotide sequence further comprises flanking short sequence regions wherein each flanking sequence region comprises one or a plurality of sequence sites for restriction endonuclease preferably endonuclease class ii erii enzymes each oligonucleotide is amplified by pcr using appropriate oligonucleotide primers to the flanking sequence regions to form a preparation of a plurality of oligonucleotides the preparation of oligonucleotides is treated then with appropriate reii enzyme s specific to the restriction sequences in the flanking sequence regions to produce flanking fragments and overlapping oligonucleotides that together comprise the desired polynucleotide sequence flanking fragments and pcr primers are removed from the mixture if desired by different methods based on size or specific labeling of the pcr primers the oligonucleotides resembling the desired target polynucleotide then assembled into.