Nucleic Acid Variant Detection via Melting Temperature Analysis

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Solution Overview

Problem

Current nucleic acid detection methods face challenges in efficiently differentiating between multiple variants of a target nucleic acid without the use of probes, particularly in real-time amplification reactions, and in accurately determining the presence or absence of specific nucleic acid variants.

Innovation Solution

The method involves using labeled oligonucleotides with light-emitting moieties and a soluble light emission modifier that quenches light emission when bound to double-stranded DNA, allowing for the amplification and differentiation of nucleic acid variants based on their melting temperatures, without the need for probes, by monitoring the signal under changing temperature conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple probes and labels are used to differentiate nucleic acid variants, then detection accuracy improves, but device complexity and cost increase

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and removes the probe component from the detection system. Instead of using probes to differentiate nucleic acid variants, the method uses the amplification primers themselves, which are already present in the reaction mixture, and detects variants through melting temperature analysis of the amplified products. This eliminates the need for separate probe molecules and simplifies the overall system architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The amplification primers serve multiple functions: they amplify the target nucleic acid and simultaneously enable variant differentiation through their sequence-specific binding and the resulting melting temperature characteristics of the amplicons. This multi-functionality replaces the need for separate probes that would otherwise be required for variant detection.

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

2Measurement precision

If multiple probes and labels are used to differentiate nucleic acid variants, then detection accuracy improves, but manufacturing cost increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The invention removes the need for expensive fluorescently-labeled probes from the reaction mixture. By using unlabeled amplification primers and detecting variants through melting temperature analysis of the amplified products, the method eliminates a significant cost component while maintaining variant differentiation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The method uses inexpensive, disposable amplification primers that are already part of the standard PCR reagent mix, replacing expensive, reusable probes. The primers are consumed in the amplification reaction, and their sequence information is leveraged for variant detection without requiring additional investment in probe synthesis and labeling.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If melting temperature analysis is performed without probes, then device complexity reduces, but measurement precision may worsen

Engineering Contradiction:
Improvedevice complexityVSAvoiddetection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The amplified nucleic acid products serve their own detection function by exhibiting characteristic melting temperatures that reveal variant information. The amplicons themselves provide the signal needed for differentiation, eliminating the need for external probes to bind and report variant presence. This self-service approach maintains detection accuracy while simplifying the system.

Inventive Principle:
Principle #25Self-service

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 efficient detection and differentiation of multiple nucleic acid variants by correlating the melting temperatures of amplicons with the presence of specific variants, reducing the need for multiple probes and labels, and improving the sensitivity and specificity of nucleic acid analysis.

Implementation Method 1

providing at least one soluble light emission modifier, which, when the modifier non-covalently binds double stranded DNA incorporating the labeled oligonucleotide, quenches light emission from the first label

Methodology Applied
Scientific EffectQuenching: Fluorescence

Data Source

PatentEP2347012B1Detection of target variants using a fluorescent label and a soluble quencher
Publication Date: 2017.04.19 ROCHE DIAGNOSTICS GMBH
  • EP2347012B1 patent drawingFigure 1
  • EP2347012B1 patent drawingFigure 2
  • EP2347012B1 patent drawing

AI summary

Methods, reaction mixtures and kits for detecting the presence or absence of a target nucleic acid variant from a selection of possible variants is described.