Error-free DNA synthesis from error-prone oligonucleotides.
Long DNA molecules encoding novel genetic elements are in broad demand. Short oligonucleotides are used as building blocks to construct longer DNA molecules. The utility of synthetic DNA constructs in biology depends on their being free of sequence errors, yet the synthetic oligonucleotides serving as their building blocks are error prone. Therefore, all DNA construction protocols struggle with the labor-intensive time-consuming task of cloning and sequencing synthetic DNA fragments, seeking an error-free one. The problem is exacerbated for longer synthetic DNA since the probability of a molecule, and hence of a clone, to be error free decreases exponentially with its length. The present invention describes a method for constructing error-free DNA molecules, by integrating recursive construction and error correction.
The present technology utilizes a recursive procedure that constructs error-free DNA molecules and their libraries from error-prone oligonucleotides. The target DNA sequence is divided in silico into overlapping oligonucleotides short enough to be synthesized directly, albeit with errors; error-prone oligonucleotides are recursively combined in vitro, forming error-prone DNA molecules; error-free fragments of these molecules are then identified, extracted and used as new, typically longer and more accurate, inputs to another iteration of the recursive construction procedure; the entire process repeats until an error-free target molecule is formed. Broad availability of such molecules, much needed since the advent of synthetic biology and modern genetic engineering, is expected to enable routine creation of new genetic material as well as offer an alternative to obtaining DNA from natural sources.