Hairpin-Seq Adapters for Ultra-Low Error DNA Sequencing
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Solution Overview
Problem
Current next-generation sequencing (NGS) methods face inefficiencies and high error rates, particularly in accurately measuring low-level somatic mutations, which are crucial for cancer detection and mutagenic potential assessment, due to limitations in adapter design and sequencing processes.
Innovation Solution
The Hairpin-Seq method employs affinity-labeled hairpin Y-adapters and a novel sequencing approach that combines dsDNA fragments with Y-adapters and hairpin adapters, allowing for efficient pair-end sequencing with high signal-to-noise read-out, reducing errors, and enabling the selection of specific ligation products to enhance sequencing efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard NGS adapter design is used, then sequencing can be performed, but error rates are high and sequencing efficiency is low
Solution Approach 1:
The adapter is divided into functionally distinct segments: a Y-shaped binding region with flow cell attachment capability, and a hairpin structure with affinity label. This segmentation allows each component to perform its specific function optimally, resolving the contradiction between sequencing accuracy and efficiency by enabling selective enrichment of valid libraries while maintaining high sequencing quality
Solution Approach 2:
The hairpin structure with affinity label serves as an intermediary that facilitates selective binding and enrichment of properly ligated DNA fragments. This intermediary mechanism enables high-efficiency selection of valid sequencing libraries without compromising sequencing accuracy, as the affinity label specifically targets and enriches only the desired library configurations
2Measurement precision
If affinity-labeled hairpin Y-adapters are used, then sequencing accuracy improves to below 1 per 1,000,000 errors, but library preparation complexity increases
Solution Approach 1:
The affinity label is pre-attached to the hairpin structure during adapter preparation, and the Y-shaped binding region is pre-configured with flow cell attachment sequences. This preliminary preparation ensures that only properly configured libraries are enriched during sequencing, achieving ultra-low error rates while streamlining the overall library preparation process through pre-validated components
Solution Approach 2:
The invention introduces specific parameter changes in the adapter structure, including the Y-shaped geometry with defined binding regions and the hairpin configuration with affinity label positioning. These parameter changes enable high-precision sequencing by ensuring only correctly ligated fragments are enriched, while the modular design keeps preparation complexity manageable
3Illumination intensity
If clonal amplification is extensively used, then signal strength increases, but error propagation and time consumption increase
Solution Approach 1:
Clonal amplification is performed preliminarily on individually captured DNA molecules before sequencing, creating sufficient signal strength for detection. The affinity-labeled hairpin adapters enable this amplification to occur in a controlled manner that preserves molecular individuality, thereby increasing signal strength without propagating errors from bulk amplification
4Length of stationary object
If read-through sequencing is used for long inserts, then complete sequence coverage is achieved, but read quality decreases
Solution Approach 1:
The sequencing process is segmented into controlled stages using the Y-shaped adapter structure. The first read sequences from one end of the insert, and the second read sequences from the other end, with the Y-shaped binding region providing stable anchoring throughout. This segmentation maintains high read quality even for long inserts by avoiding the quality degradation associated with continuous read-through sequencing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Hairpin-Seq achieves significantly higher sequencing efficiency and accuracy, reaching error rates below 1 per 1,000,000 positions, enabling reliable detection of subclonal mutations and improving the analysis of somatic evolution, cancer treatment monitoring, and mutagenic potential assessment, with improved library preparation and reduced need for clonal amplification.
Implementation Method 1
combining dsDNA fragments with Y-adapters and hairpin adapters comprising an affinity-label under conditions wherein the adapters ligate to fragments
Implementation Method 2
the ligated construct to be sequenced (hairpin) will form polonies on the flow cell and the size of those polonies depends on the length of the single stranded parts of the Y-adapters
Implementation Method 3
After synthesis is completed the dsDNA molecule is denatured and the original strand is washed away
Data Source
AI summary
DNA is sequenced by: (a) combining dsDNA fragments with Y-adapters and hairpin adapters comprising an affinity-label under conditions wherein the adapters ligate to fragments forming a mixture of fragment inserts flanked by two Y-adapters, a Y-adapter and a hairpin adapter, and two hairpin adapters; and (b) sequencing the selected fragment inserts with sequencing primers selecting for the Y-adapters.