Oligo Modification for NGS Performance:
From Library Preparation to Target Capture
Why Oligo Design Matters in the NGS Workflow
In the Next-Generation Sequencing (NGS) workflow, oligonucleotides (oligos) play an important role throughout both library preparation and target capture processes.
For example, adapters influence the efficiency of DNA fragment ligation, while index primers enable accurate sample identification in multiplex sequencing. In addition, blocking reagents help suppress non-specific binding, and probes selectively capture target regions during the target capture hybridization process.
However, unmodified oligos may introduce several challenges due to structural and chemical limitations. Common issues include adapter dimer formation, reduced library yield, indexing variability, and increased off-target hybridization. These factors can ultimately affect the accuracy and reproducibility of NGS data.
To address these challenges, Celemics has applied oligo modification technology across adapters, index primers, blocking reagents, and probes. In this blog, we highlight how oligo modification can improve the performance of NGS library preparation and target capture workflows based on experimental results.
Improved Library Preparation with Modified Adapters
During NGS library preparation, adapter dimer formation is a common issue, particularly when working with low-input DNA samples. Excessive adapter dimers can reduce effective library yield and negatively impact sequencing efficiency. When comparing modified adapters with unmodified adapters, the following improvements were observed:
- Reduced adapter dimer formation
- Increased library yield across all DNA input conditions
- Stable library quality even in low-input samples
These results suggest that adapter modification improves ligation efficiency and helps suppress adapter dimer formation, leading to a more stable and efficient library preparation workflow.
More Stable Multiplex Sequencing with Modified Index Primers
Index primers play a critical role in multiplex sequencing, allowing multiple samples to be analyzed simultaneously. However, unmodified index primers may cause variability in library yield or reduced PCR reproducibility.
When modified index primers were compared with unmodified index primers, the following improvements were observed:
- Increased library yield
- Reduced variability between replicates
- More stable PCR amplification performance
These results indicate that index primer modification contributes to more reliable library preparation in multiplex sequencing experiments.
Enhanced Target Capture with Modified Blocking Reagents and Probes
In target capture sequencing, hybridization efficiency significantly affects the on-target ratio, coverage, and overall sequencing data quality. These factors also directly influence the accuracy of downstream Bioinformatics (BI) analysis.
If blocking is insufficient or probe binding efficiency is low, off-target capture may increase and coverage may become uneven.
When comparing modified and unmodified oligos, the following improvements were observed:
- Reduced off-target binding when modified blocking reagents were used
- Increased on-target ratio across both panels
- Improved coverage and uniformity, particularly in large panels
- More consistent target capture performance across replicates
The Impact of Oligo Modification on the NGS Workflow
Celemics integrates oligo modification technology across key components of the NGS workflow to ensure stable performance and reproducible data generation. By generating more reliable and reproducible sequencing data, these improvements can also support more accurate Bioinformatics (BI) analysis.
Explore Oligo-Optimized NGS Solutions
Oligo design and modification can significantly impact sequencing performance, from library preparation efficiency to target capture accuracy. If you’re looking to improve NGS workflow stability and data reproducibility, explore how Celemics solutions can support your research.