Combinatorial PCR Method for Efficient, Selective Oligo Retrieval from Complex Oligo Pools br

With the rapidly decreasing cost of array-based oligo synthesis, large-scale oligo pools offer significant benefits for advancedapplications including gene synthesis, CRISPR-based gene editing,and DNA data storage. The selective retrieval of specific oligos fromthese complex pools traditionally uses polymerase chain reaction(PCR). Designing a large number of primers to use in PCR presents aserious challenge, particularly for DNA data storage, where the size ofan oligo pool is orders of magnitude larger than other applications.Although a nested primer address system was recently developed toincrease the number of accessiblefiles for DNA storage, it requiresmore complicated lab protocols and more expensive reagents toachieve high specificity, as well as more DNA address space. Here, wepresent a new combinatorial PCR method that has none of thosedrawbacks and outperforms in retrieval specificity. In experiments, we accessed threefiles that each comprised 1% of a DNAprototype database that contained 81 differentfiles and enriched them to over 99.9% using our combinatorial primer method. Ourmethod provides a viable path for scaling up DNA data storage systems and has broader utility whenever one must access a specific target oligo and can design their own primer regions