Split-Cycle TAPE Amplification for Rare Mutation Detection
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Solution Overview
Problem
Current methods for quantitative detection of rare target sequences in nucleic acid samples face challenges in sensitivity and accuracy due to primer depletion and competition, leading to inaccurate differentiation between mutant and wild-type sequences.
Innovation Solution
The use of split-cycle and tagged amplicon primer extension (TAPE) methods, which involve partitioning the sample into discrete reaction chambers and employing 5′-tailed primers and flanking primers with specific annealing temperatures and tail regions to enhance specificity and fidelity of amplification, preventing primer depletion and improving separation between single-positive and double-positive partitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amplification methods are used to detect rare target sequences, then amplification efficiency is maintained, but sensitivity and accuracy deteriorate due to primer depletion and competition
Solution Approach 1:
The patent divides the amplification process into two distinct phases: initial amplification cycles using allele-specific primers to append primer binding sites, followed by subsequent amplification cycles using flanking primers for high-fidelity amplification. This segmentation resolves the contradiction by allowing efficient amplification in the first phase while ensuring accuracy in the second phase, preventing primer depletion and competition issues that plague conventional single-phase methods.
Solution Approach 2:
The patent performs preliminary action by using the initial set of amplification cycles to append high-temperature or low-temperature primer binding sites to target sequences before the main amplification phase. This preliminary step prepares the target sequences for subsequent high-fidelity amplification, ensuring that rare targets are properly marked and differentiated before the bulk amplification occurs, thereby improving detection accuracy without sacrificing reliability.
2Measurement precision
If allele-specific primers with low annealing temperature are used, then amplification of rare targets is enhanced, but specificity deteriorates due to mis-priming
Solution Approach 1:
The patent segments the amplification process into two phases: initial cycles with low annealing temperature to enhance sensitivity and capture rare targets, followed by subsequent cycles with high annealing temperature to restore specificity. This temporal segmentation allows the system to benefit from both low-temperature sensitivity and high-temperature specificity, resolving the contradiction between detection sensitivity and amplification specificity.
Solution Approach 2:
The patent employs periodic action by alternating between different annealing temperature regimes in successive amplification cycles. The initial period uses lower annealing temperatures to maximize target capture, then transitions to higher annealing temperatures for specific amplification. This periodic temperature variation allows the system to achieve both sensitive detection and specific amplification at different time points in the amplification process.
3Productivity
If standard PCR amplification is used, then amplification speed is maintained, but accuracy deteriorates due to polymerase-mediated errors
Solution Approach 1:
The patent segments the amplification process into initial cycles that focus on target enrichment and subsequent cycles that focus on high-fidelity amplification. By separating these functions into distinct phases, the system maintains amplification efficiency in the initial phase while ensuring sequence fidelity in the subsequent phase, resolving the contradiction between productivity and measurement precision.
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
This approach increases the sensitivity and accuracy of rare mutation detection by reducing mis-priming and polymerase-mediated errors, allowing for precise quantitation of wild-type and mutant sequences through well-separated single- and double-positive regions.
Implementation Method 1
a pair of allele-specific amplification primers having a relatively low annealing temperature are used to append a high-temperature primer binding site to the target sequence in an initial set of nucleic acid amplification cycles
Implementation Method 2
The initial set of nucleic acid amplification cycles include a low temperature annealing step
Implementation Method 3
a pair of flanking amplification primers that hybridize to the high-temperature primer binding site provide high fidelity and highly specific amplification
Implementation Method 4
The subsequent set of nucleic acid amplification cycles include a higher temperature annealing step
Implementation Method 5
nucleic acid amplification cycles
Data Source
AI summary
Methods and compositions are provided for improved nucleic acid amplification assays. In some embodiments, the nucleic acid amplification assay is a tagged amplicon primer extension (TAPE) nucleic acid amplification reaction.