Duplex Consensus Sequencing for Rare Variant Error Correction
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Solution Overview
Problem
Existing methods for sequencing DNA fail to accurately detect subpopulations below 0.1% mutations, reflecting significant technical artifacts from DNA damage and PCR errors, obscuring rare variants in heterogeneous populations.
Innovation Solution
The use of single molecule identifier (SMI) adaptors and duplex consensus sequencing (DCS) to ligate to double-stranded nucleic acids, amplify, and sequence both strands, allowing error correction by confirming mutations present on both strands, thereby reducing artifactual errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional sequencing methods are used, then sequencing speed and throughput are improved, but error rate increases and detection precision of rare variants deteriorates
Solution Approach 1:
The patent segments the sequencing process into independent single-molecule reactions, where each DNA fragment is sequenced individually rather than in bulk. This is achieved through solid-supported single-molecule sequencing, allowing parallel processing of many individual molecules while maintaining the ability to track and correct errors at the single-molecule level, thus resolving the contradiction between throughput and precision.
Solution Approach 2:
The patent implements feedback mechanisms by using reversible terminator nucleotides that provide real-time signal feedback during sequencing. The system monitors incorporation events and uses this feedback to control the sequencing process, enabling error detection and correction while maintaining high throughput through automated feedback-driven cycle control.
2Measurement precision
If PCR amplification is used to increase signal, then detection sensitivity improves, but artifactual errors from DNA damage and PCR mistakes increase
Solution Approach 1:
The patent extracts and removes the harmful PCR amplification step from the sequencing workflow. By using solid-supported single-molecule sequencing, the method directly sequences individual DNA fragments without requiring PCR amplification, thereby eliminating PCR-induced artifacts while maintaining sufficient signal through direct detection on solid supports.
Solution Approach 2:
The patent uses reversible terminator nucleotides that create temporary copies during the sequencing process. These terminators allow controlled synthesis and signal generation without permanent amplification, enabling detection sensitivity through controlled copying while avoiding the harmful effects of extensive PCR amplification.
3Measurement precision
If deep sequencing is performed to detect rare variants, then detection sensitivity improves, but error accumulation from multiple sequencing cycles increases
Solution Approach 1:
The patent replaces traditional mechanical/chemical amplification-based sequencing with a direct single-molecule detection system. By using solid-supported sequencing with reversible terminators, the method achieves deep sequencing capability without the error accumulation inherent in repeated amplification cycles, maintaining both sensitivity and reliability.
Solution Approach 2:
The patent changes the fundamental parameters of the sequencing process by working at the single-molecule level with controlled reversible termination. This allows deep sequencing through repeated controlled cycles on individual molecules rather than through amplification of populations, reducing error accumulation while maintaining detection sensitivity for rare variants.
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
DCS achieves a 1000-fold reduction in sequencing errors, enabling detection of rare variants down to 1/10,000, surpassing the sensitivity of previous methods.
Implementation Method 1
extension of the primer with a DNA polymerase
Implementation Method 2
digestion of the double-stranded target nucleic acid with a restriction endonuclease
Implementation Method 3
transcription of the extension product with T7 RNA polymerase
Data Source
AI summary
Next Generation DNA sequencing promises to revolutionize clinical medicine and basic research. However, while this technology has the capacity to generate hundreds of billions of nucleotides of DNA sequence in a single experiment, the error rate of approximately 1% results in hundreds of millions of sequencing mistakes. These scattered errors can be tolerated in some applications but become extremely problematic when “deep sequencing” genetically heterogeneous mixtures, such as tumors or mixed microbial populations. To overcome limitations in sequencing accuracy, a method Duplex Consensus Sequencing (DCS) is provided. This approach greatly reduces errors by independently tagging and sequencing each of the two strands of a DNA duplex. As the two strands are complementary, true mutations are found at the same position in both strands. In contrast, PCR or sequencing errors will result in errors in only one strand. This method uniquely capitalizes on the redundant information stored in double-stranded DNA, thus overcoming technical limitations of prior methods utilizing data from only one of the two strands.