Dual index adapters with UMIs resolve index hopping and increase sensitivity of variant detection

The rapid increase in throughput of next generation sequencing (NGS) platforms is changing the genomics landscape. Typically, adapters containing sample indexes are added during library construction to allow multiple samples to be sequenced in parallel. Some strategies also introduce a unique molecular identifier (UMI) within the adapter to correct for PCR and sequencing errors. When a UMI is added, reads are assigned to each sample based on their associated sample index, and the UMI is used for error correction during data analysis. For simplicity, a single adapter that is suitable for a variety of applications would be ideal. xGen™ Dual Index UMI Adapters take the guesswork out of adapter design and ordering. These adapters, created for Illumina sequencers, are compatible with standard library preparation methods and may be sequenced in different modes depending on your application. In addition to unique, dual indexes, the adapters contain a molecular barcode in an optional read position. We discuss how unique, dual indexes mitigate sample index hopping for multiplexed sequencing and demonstrate how UMIs reduce false positives to improve detection of low-frequency variants.