Methods for seamless nucleic acid assembly

A method for nucleic acid synthesis and assembly, comprising:

• a. providing predetermined sequences for a first double stranded nucleic acid and a second double stranded nucleic acid, wherein the first double stranded nucleic acid comprises in 5′ to 3′ order:
• a 5′ flanking adapter sequence, an insert sequence, a homology sequence, and a 3′ flanking adapter sequence, and wherein the second double stranded nucleic acid comprises in 5′ to 3′ order:
• a 5′ flanking adapter sequence, an insert sequence, a homology sequence, and a 3′ flanking adapter sequence;
• b. synthesizing a plurality of double stranded nucleic acids encoding for the predetermined sequences;
• c. annealing a universal primer comprising uracil at a terminal end of the first double stranded nucleic acid and the second double stranded nucleic acid;
• d. amplifying the first double stranded nucleic acid and the second double stranded nucleic acid using a uracil incompatible polymerase to form amplification products;
• e. mixing the amplification products to form a mixture;
• and
• f. amplifying the mixture;
• thereby forming an assembled nucleic acid.