Nucleic Acid Library End Modification for Uniform Coverage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nucleic acid amplification techniques, such as PCR, require prior knowledge of the template sequence for specific amplification, leading to increased complexity and cost when dealing with complex mixtures like genomic DNA fragments, and suffer from over-representation of terminal sequences in 5' and 3' modified libraries, which affects sequencing and cloning efficiency.
Innovation Solution
A method to generate a 5' and 3' modified library of template polynucleotide molecules by fragmenting primary polynucleotides, ligating adapters, and performing amplification reactions with modified primers to prevent over-representation of end sequences, ensuring uniform coverage and reducing bias in sequencing and cloning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If PCR amplification is performed on complex mixtures of templates without prior sequence knowledge, then amplification of diverse templates is enabled, but over-representation of terminal sequences occurs in the resulting library
Solution Approach 1:
The patent applies preliminary action by performing end-modification of primary polynucleotide molecules before fragmentation and library construction. Specifically, the 5' and 3' ends are modified with blocking groups or chemical modifications that prevent these terminal sequences from being over-represented during subsequent amplification steps. This pre-treatment ensures that when the library is generated, terminal sequences do not dominate the representation, thereby resolving the contradiction between amplifying complex mixtures without prior knowledge and maintaining uniform sequence representation.
2Ease of manufacture
If standard library preparation methods are used, then library generation is simplified, but terminal sequences are over-represented affecting sequencing and cloning efficiency
Solution Approach 1:
The patent incorporates end-modification as a preliminary step in the library preparation workflow, performed before fragmentation and adapter ligation. This modification step, while adding a process step, uses commercially available enzymes and reagents that integrate smoothly into existing workflows. The benefit is that sequencing and cloning efficiency is dramatically improved by eliminating terminal sequence over-representation, which would otherwise cause biases and artifacts in downstream applications.
3Loss of time
If 5' and 3' modified libraries are generated without end modification, then library construction is faster, but over-representation of end sequences reduces sequencing accuracy
Solution Approach 1:
The patent performs end-modification as a preliminary action that prevents terminal sequence over-representation before it can affect sequencing. The modification involves treating the 5' and 3' ends of primary polynucleotides with specific enzymes or chemical reagents that add blocking groups or modify the ends in a way that prevents them from being preferentially amplified or sequenced. This short additional step significantly improves sequencing accuracy by eliminating the bias toward terminal sequences.
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
The method effectively reduces the over-representation of terminal sequences, achieving uniform coverage and improving the efficiency of nucleic acid sequencing and cloning by maintaining the relative abundance of nucleic acid sequences in the library, thereby simplifying the amplification of complex mixtures without prior sequence knowledge.
Implementation Method 1
a) Fragmenting the modified primary polynucleotide molecules to produce target polynucleotide duplexes
Implementation Method 2
b) ligating adapter polynucleotides to the two ligatable termini of the unmodified target polynucleotide duplexes to form one or more adapter-target-adapter constructs
Implementation Method 3
c) carrying out an amplification reaction, wherein a primer oligonucleotide is annealed to both 5'-terminal adapter portions of each of the adapter-target-adapter constructs and extended by sequential addition of nucleotides to form extension products
Data Source
AI summary
The invention relates to a method of preparing a 5′ and 3′ modified library of template polynucleotides and also the use of the 5′ and 3′ modified library of templates in methods of solid-phase nucleic acid amplification. In particular, the invention relates to a method of preparing a 5′ and 3′ modified library of template polynucleotides which have common sequences at their 5′ ends and at their 3′ ends, wherein over-representation of “end” sequences of the primary polynucleotide molecules from when the 5′ and 3′ modified library is generated is greatly reduced or prevented.