Libraries constructed with IDT's Duplex UMIs (Unique Molecule Identifiers) adapters will have additional UMI bases added at the beginning of the reads that can be used to more accurately detect read duplicates as well as to improve variant calling specificity. The documents below describe the adapters and suggest analyses that can be employed to leverage the additional UMI information. Users are highly recommended to trim the first 5 bases from the sequenced reads and have the option of using the first 3 bases from each read for downstream duplex UMI analysis.
If you have been provided with BAM files you will find the UMI sequence in the RX tag, which can be recognized by UMI-specific analysis tools.