Cationic Nucleic Acid Terminators for Sanger Sequencing Artifacts
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Solution Overview
Problem
Current Sanger dideoxy sequencing methods face challenges due to the preferential incorporation of deoxynucleotides over dideoxynucleotides by non-mutated polymerases, leading to low dideoxynucleotide incorporation and high artifacts in DNA sequencing.
Innovation Solution
A cationically charged nucleic acid terminator is used in combination with a discriminatory polymerase, allowing for equivalent incorporation of deoxynucleotides and dideoxynucleotides, reducing dye terminator artifacts through size-dependent electrophoretic separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-mutated polymerases are used in Sanger sequencing, then deoxynucleotide incorporation is efficient, but dideoxynucleotide incorporation is too low resulting in high artifacts and background
Solution Approach 1:
The patent modifies the charge parameter of dideoxynucleotides by attaching cationic groups, changing their electrophoretic mobility and polymerase interaction properties. This allows differentiation between ddNTPs and dNTPs based on charge, enabling the use of non-mutated polymerases while maintaining reliable sequencing by reducing artifact formation through charge-based discrimination during electrophoresis
2Reliability
If mutated polymerases are used to improve dideoxynucleotide incorporation, then sequencing reliability improves, but device complexity and mutation maintenance requirements increase
Solution Approach 1:
Instead of mutating the polymerase, the patent changes the charge parameter of the dideoxynucleotides themselves. This approach achieves reliable dideoxynucleotide incorporation with non-mutated polymerases by using charge-modified terminators that have altered electrophoretic properties, thereby avoiding the complexity of maintaining and managing mutated polymerase variants
Solution Approach 2:
The patent introduces cationic groups as intermediaries attached to dideoxynucleotides. These cationic moieties serve as mediators that alter the interaction between polymerases and dideoxynucleotides, enabling efficient incorporation without polymerase mutation, while also providing charge-based discrimination during electrophoresis to identify termination events
3Measurement precision
If multiple fluorescent labels are used to distinguish different polynucleotides, then detection precision improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the charge parameter of dideoxynucleotides by attaching cationic groups at different positions or with different characteristics for each base type. This charge-based differentiation enables distinction between different polynucleotides using a single labeling strategy, simplifying manufacturing compared to traditional multi-fluorophore approaches while maintaining high detection precision through charge-to-mass ratio differences
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 DNA sequencing by minimizing artifacts and improving the discrimination between deoxynucleotides and dideoxynucleotides, enhancing the reliability of sequencing results.
Implementation Method 1
separating the reacted cationically charged nucleic acid terminator on the basis of size
Data Source
AI summary
Disclosed are methods and kits applicable to sequencing methods, such as Sanger dideoxy sequencing methods. The methods and kits disclosed utilize a cationically charged nucleic acid terminator in combination with a discriminatory polymerase.