Abstract: Disclosed herein is a method for synthesizing a desired nucleic acid sequence. The method comprises dividing the desired sequence into a plurality of partially overlapping segments; optimizing the melting temperatures of the overlapping regions of each segment to disfavor hybridization to the overlapping segments which are non-adjacent in the desired sequence; allowing the overlapping regions of single stranded segments which are adjacent to one another in the desired sequence to hybridize to one another under conditions which disfavor hybridization of non-adjacent segments; and filling in, ligating, or repairing the gaps between the overlapping regions, thereby forming a double-stranded DNA with the desired sequence. Also disclosed is a method for preventing errors in the synthesis of the nucleic acid sequence.