Parallel Amplification for Low Frequency Genetic Variant Detection
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Solution Overview
Problem
Current genetic sequencing methods struggle to accurately detect and quantify low-frequency genetic variants, particularly somatic mutations, due to issues like allelic dropout, amplification bias, and high costs, which limits their applicability in clinical diagnostics and research.
Innovation Solution
The method involves performing multiple parallel amplification reactions on a single sample using unique pairs of primers with index sequences and adapter sequences to generate overlapping amplicons, which are then sequenced and analyzed to determine alternate allele frequencies, allowing for deep coverage and cost-effective detection of low-frequency genetic variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional genetic sequencing methods (WGS, WES) are used to detect somatic mutations, then detection sensitivity is improved when most cells carry the mutation, but detection accuracy deteriorates for low-frequency variants due to allelic dropout and amplification bias
Solution Approach 1:
The patent segments the amplification process into multiple independent parallel reactions, each with unique primers targeting the same genomic region. This segmentation allows independent measurement of allelic fractions across multiple assays, reducing the impact of allelic dropout in any single reaction and improving overall detection reliability for low-frequency variants
Solution Approach 2:
The patent applies local quality by designing primer pairs with different binding specificities for the same target region, where each primer pair has optimized local characteristics (binding affinity, specificity) suited for detecting variants at different frequencies. This allows tailoring the amplification conditions to the specific detection needs of low-frequency somatic mutations
2Reliability
If multiple parallel amplification reactions with unique primers are performed, then detection accuracy for low-frequency variants is improved, but cost and complexity increase
Solution Approach 1:
The patent employs universal adapter sequences that can be used across all primer pairs in the panel, allowing multiplexing of multiple amplification reactions in a single sequencing run. This universal adapter design reduces the need for separate processing of each reaction, thereby reducing overall complexity and cost while maintaining the benefits of multiple parallel measurements
Solution Approach 2:
The patent combines multiple amplification reactions by pooling the amplicons from different primer pairs before sequencing. This merging approach allows simultaneous analysis of multiple targets in a single sequencing run, reducing per-sample costs and simplifying workflow while preserving the detection accuracy benefits of multiple independent measurements
3Reliability
If primers are avoided in areas with known genetic variation, then allelic dropout from common variants is reduced, but detection capability is lost for rare and private alleles
Solution Approach 1:
The patent performs preliminary action by conducting multiple independent amplification reactions with different primer pairs before sequencing. This allows the system to overcome primer binding issues at known variant sites by having alternative primers that may not be affected by the same variant, thereby maintaining detection capability for both common and rare alleles
Solution Approach 2:
The patent creates multiple copies of the target region through different primer pairs, where each primer pair generates an independent copy of the amplicon. This copying approach ensures that if one primer pair fails to amplify due to a variant at the binding site, other copies from different primer pairs can still be detected, preserving versatility for detecting rare and private alleles
4Measurement precision
If deep sequencing coverage is achieved through multiple amplification reactions, then detection of ultra-low allelic fractions is improved, but cost-effectiveness deteriorates
Solution Approach 1:
The patent applies partial action by performing a limited number (e.g., 2-4) of parallel amplification reactions per target region, which provides sufficient statistical power to detect ultra-low allelic fractions without the excessive cost of whole-genome sequencing at equivalent depth. This partial approach focuses sequencing resources on specific regions of interest while maintaining cost-effectiveness
Data Source
AI summary
Methods are described for the detection of low frequency genetic variants, such as somatic mosaic variants. The methods comprise parallel amplification reactions of a target nucleic acid sequence to generate overlapping amplicons, pooled sequencing of the amplicons, and demultiplexed detection of low frequency variants.