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Blocking Oligos for NGS Target Enrichment Applications

xGen™ Blocking Oligos

xGen™ Blocking Oligos are essential compo­nents of the target enrichment process for next generation sequencing (NGS). During sample preparation, platform-specific adapters are added to all library fragments. These adapter sequences can interact with each other during hybridization-based en­richment, causing a daisy-chain effect, and thereby increasing undesired enrichment of off-target sequences. Blocking oligos, added during hybridization of the capture reagents, bind to the adapter sequences to prevent them from hybridizing to each other. Using high-quality blocking oligonu­cleotides enhances this effect and increases the number of “reads on-target”, a measure of the amount of sequence information that corresponds to the target region(s) of interest, observed after sequencing.

xGen Blocking Oligos are available at a defined yield of 10 or 25 nmoles and can be ordered using our intuitive online interface. Now you can easily:

  • Obtain a complete set of barcode- specific blocking oligonucleotides.
  • Replace individual oligos in an existing set.
  • Configure “universal” blocking oligos by incorporating deoxyinosine modifica­tions or degenerate bases.
  • Enhance binding efficiency by request­ing HPLC purification.
  • Add terminal modifications, such as a 3’ C3 Spacer, to prevent nonspecific ampli­fication of the blocking oligos.

Common xGen Blocking Oligo Sets

Illumina® TruSeq®

Illumina® TruSeq® HT

Roche 454 Adapters

Ion Torrent™ Adapters

For more information, or to order xGen Blocking Oligos, go to www.idtdna.com/xgen and select xGen Blocking Oligos, or email us at xgen@idtdna.com.