Nanopore Electrical Signal Analysis for Bisulfite-Free Methylation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining DNA methylation, such as bisulfite sequencing, face challenges including DNA degradation, CG bias, and inefficiency in sequencing long DNA molecules, necessitating the development of bisulfite-free techniques for accurate and sensitive base modification detection.
Innovation Solution
The use of nanopore sequencing to analyze electrical current signals for detecting base modifications like 5mC without pre-treatment, employing features derived from sequencing signals and statistical values of signal segments to identify methylation status, enabling the detection of various methylation types without enzymatic or chemical conversions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If bisulfite sequencing is used to measure DNA methylation, then methylation detection capability is achieved, but DNA degradation occurs and sequencing efficiency for long molecules is reduced
Solution Approach 1:
The patent extracts and eliminates the bisulfite conversion step from the traditional sequencing workflow. By using nanopore sequencing to directly detect base modifications through electrical signal analysis without chemical treatment, the method removes the source of DNA degradation while preserving methylation detection capability
Solution Approach 2:
The patent replaces the chemical conversion mechanism (bisulfite treatment) with a physical detection mechanism (nanopore electrical signal analysis). The nanopore system detects base modifications through changes in ionic current as DNA passes through the pore, substituting chemical modification with physical measurement
2Measurement precision
If bisulfite conversion is applied to detect base modifications, then methylation status can be determined, but strong CG biases are created reducing signal-to-noise ratio
Solution Approach 1:
The patent removes the bisulfite conversion step that causes CG bias. By directly sequencing native DNA with nanopore technology, the method preserves the natural base composition and eliminates the artificial CG enrichment effect, maintaining better signal-to-noise ratios
Solution Approach 2:
The patent changes the detection parameter from chemical conversion efficiency to electrical signal characteristics. Instead of measuring conversion efficiency that creates bias, the system analyzes ionic current patterns that naturally reflect base composition without distortion
3Measurement precision
If traditional sequencing methods are used, then base modification detection is achieved, but complex pre-treatment steps are required
Solution Approach 1:
The patent extracts and removes multiple pre-treatment steps (bisulfite conversion, enzymatic treatment, chemical labeling) from the sequencing workflow. The nanopore system directly sequences native DNA, eliminating complex preparation procedures while maintaining detection accuracy
Solution Approach 2:
The nanopore sequencing system performs self-service detection by directly analyzing native DNA molecules without requiring external chemical or enzymatic assistance. The system's own electrical measurement capability suffices to detect base modifications, eliminating the need for auxiliary treatment steps
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 allows for sensitive and specific detection of base modifications, improving the analysis of methylation profiles in biological samples, aiding in the identification of developmental disorders and distinguishing between DNA origins, with potential for cost-effective and portable sequencing.
Implementation Method 1
nanopore sequencing is a type of sequencing that is attractive for not needing chemical labeling of a sample. Detection of base modifications with nanopore sequencing may be relatively low cost and efficient.
Data Source
AI summary
Systems and methods for determining base modifications using electrical signals and other data is described herein. Embodiments can make use of features derived from electrical signals related to sequencing, such as those acquired from using a nanopore, that are affected by the various base modifications, as well as an identity of nucleotides in a window around a target position whose methylation status is determined. Other features may include a vector of statistical values of a segment of the electrical signal corresponding to the nucleotide and a statistical value of the electrical signal in a window in a region of the nucleic acid molecule. The detected base modifications can be used for additional analysis of a biological sample.