CODEC enables ‘single duplex’ sequencing

Detecting mutations as rare as a single molecule is crucial in many fields such as cancer diagnostics and aging research but remains challenging. Third generation sequencers can read a double-stranded DNA molecule (a ‘single duplex’) in whole to identify true mutations on both strands apart from false mutations on either strand but with limited accuracy and throughput. Although next generation sequencing (NGS) can track dissociated strands with Duplex Sequencing, the need to sequence each strand independently severely diminishes its throughput. Here, we developed a hybrid method called Concatenating Original Duplex for Error Correction (CODEC) that combines the massively parallel nature of NGS with the single-molecule capability of third generation sequencing. CODEC physically links both strands to enable NGS to sequence a single duplex with a single read pair. By comparing CODEC and Duplex Sequencing, we showed that CODEC achieved a similar error rate (10−6) with 100 times fewer reads and conferred ‘single duplex’ resolution to most major NGS workflows. ### Competing Interest Statement The authors have filed a patent application on this method. V.A.A. is a member of the scientific advisory boards of AGCT GmbH and Bertis Inc. T.R.G. has advisor roles at Foundation Medicine, GlaxoSmithKline, and Sherlock Biosciences.