Sequencing Bias Correction via Control Fragments

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Solution Overview

Problem

Current genome-wide sequencing methods, such as genome-wide bisulfite sequencing, face challenges in clinical diagnostics due to the need for large sample sizes and low sensitivity and specificity in detecting epigenetic modifications and genetic mutations, especially in heterogeneous clinical samples.

Innovation Solution

The method involves sequencing a target region and a set of polynucleotide fragments with nucleotide tags to distinguish between different nucleotides at a specific position, allowing for deep sequencing and determination of sequencing bias to improve detection sensitivity and specificity using equimolar amounts of fragments with different nucleotides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If genome-wide bisulfite sequencing is performed to detect epigenetic modifications, then detection sensitivity and specificity are improved, but sample size requirements increase and the method becomes less suitable for clinical diagnostics

Engineering Contradiction:
Improvedetection sensitivity and specificityVSAvoidsample size
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The method segments the sequencing process by separating target region sequencing from control fragment sequencing. Control polynucleotide fragments with known sequences and defined nucleotide compositions are sequenced alongside target regions, allowing bias correction through comparison. This segmentation enables accurate detection in small samples by using controls to calibrate sequencing behavior.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the parameter of nucleotide composition in control fragments to match expected target region compositions (e.g., equimolar amounts of different nucleotides). By adjusting control fragment parameters to reflect target characteristics, the method enables accurate bias measurement and correction for small clinical samples, improving detection sensitivity without requiring large sample sizes.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If deep sequencing is performed to detect nucleotides in heterogeneous polynucleotide samples, then detection accuracy is improved, but sequencing bias increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidsequencing bias
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The method implements feedback by using control polynucleotide fragments with known nucleotide compositions to measure sequencing bias, then applying this measured bias information to correct target region sequencing results. The control fragments provide feedback on sequencing performance, enabling accurate detection in heterogeneous samples by compensating for position-specific and nucleotide-specific biases.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Control polynucleotide fragments serve as intermediaries between the sequencing process and target region analysis. These fragments with defined sequences and compositions mediate the measurement of sequencing bias, allowing the system to characterize and correct bias without directly analyzing the heterogeneous target samples. The intermediaries enable indirect measurement and correction of sequencing artifacts.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If genome-wide sequencing is adapted for clinical diagnostics, then diagnostic capability is improved, but the method complexity and cost increase

Engineering Contradiction:
Improvediagnostic capabilityVSAvoidmethod complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control polynucleotide fragments serve multiple functions: they measure sequencing bias, calibrate detection sensitivity, and provide reference standards for quality control. This multi-functionality reduces the need for separate validation experiments and simplifies the overall diagnostic workflow, making genome-wide sequencing more adaptable for clinical use without proportionally increasing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The method performs preliminary sequencing of control fragments with known compositions before or alongside target region sequencing to establish baseline bias parameters. This preliminary action enables pre-calibration of the sequencing system, allowing accurate diagnostic detection in clinical samples without requiring complex post-hoc corrections or additional validation steps.

Inventive Principle:
Principle #10Preliminary action

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 enables accurate detection of nucleotides in small sample sizes, reducing sequencing bias and enhancing the sensitivity and specificity of epigenetic and genetic mutation detection, making genome-wide sequencing more suitable for clinical diagnostics.

Implementation Method 1

A reaction mixture for sequencing the target region and the set of polynucleotide fragments may include one or more primers that hybridize specifically to the target region and one or more primers that hybridize specifically to the set of polynucleotide fragments

Methodology Applied
Scientific EffectHybridization:

Data Source

PatentEP2956553B1Methods and kits for identifying and adjusting for bias in sequencing of polynucleotide samples
Publication Date: 2020.01.08 MDXHEALTH
  • EP2956553B1 patent drawingFigure 1
  • EP2956553B1 patent drawingFigure 2
  • EP2956553B1 patent drawingFigure 3

AI summary

Disclosed are methods for determining one or more nucleotides at one or more nucleotide positions of a polynucleotide sample, the polynucleotide sample comprising heterogeneous polynucleotides having different nucleotides at the nucleotide positions. The disclosed methods may be utilized to control for sequencing bias during sequencing of the polynucleotide sample. Suitable samples may include patient samples for use in diagnosing, prognosing, and treating the patient.