Splinted Ligation Adapter Tagging for Low-Input DNA Library Prep
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Solution Overview
Problem
Current methods for preparing DNA libraries, particularly for whole genome bisulfite sequencing, are inefficient and require high DNA input amounts, making them unsuitable for small samples or clinical applications.
Innovation Solution
A method involving bisulfite treatment of nucleic acids, followed by adapter tagging using adapters with degenerate splints, and subsequent PCR amplification to generate copies of the ligated nucleic acid strands, enabling efficient library preparation with low DNA input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional DNA library preparation methods are used, then the library can be prepared with standard protocols, but high DNA input amounts are required which makes them unsuitable for small samples
Solution Approach 1:
The library preparation process is divided into distinct modules: (1) bisulfite treatment of nucleic acids, (2) adapter tagging with degenerate splints, and (3) PCR amplification. This segmentation allows each step to be optimized independently, enabling efficient preparation from low DNA input while maintaining overall productivity.
Solution Approach 2:
Adapters with degenerate splints serve as intermediary molecules that bridge the bisulfite-treated nucleic acid strands and enable subsequent PCR amplification. These adapters facilitate the ligation and amplification processes, allowing efficient library preparation even when starting with small DNA amounts.
2Quantity of substance
If traditional adapter tagging methods are used, then the process is straightforward, but they are inefficient for small DNA samples
Solution Approach 1:
The method employs parameter changes including: (1) chemical modification of cytosines through bisulfite treatment, (2) use of degenerate splint sequences in adapters to accommodate sequence variations, and (3) optimization of PCR conditions. These parameter changes enable reliable library preparation from small DNA samples by adapting the process to work with limited material.
3Adaptability or versatility
If high DNA input amounts are used, then traditional methods work reliably, but this limits applicability to clinical and small sample applications
Solution Approach 1:
The developed method is universal and can be applied to various sample types including clinical samples, forensic samples, and small biological specimens. The adapter tagging system with degenerate splints and the PCR amplification step make the protocol versatile for different applications while maintaining efficiency across all sample types.
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 method allows for sensitive and straightforward DNA library preparation, even with small DNA amounts, thereby overcoming the limitations of traditional methods and facilitating genome-wide DNA methylation analysis.
Implementation Method 1
treating a nucleic acid with bisulfite to convert non-methylated cytosines in the nucleic acid into uracils while leaving methylated cytosines unchanged
Implementation Method 2
ligating a first adapter to a 3′ end of the treated nucleic acid strand to thereby form a once adapter ligated nucleic acid strand
Implementation Method 3
performing polymerase chain reaction (PCR) amplification on the twice ligated nucleic acid strand to thereby generate copies of the twice ligated nucleic acid strand
Data Source
AI summary
A method comprises (a) providing single-stranded DNA; (b) ligating a first adapter to a 3′ end of the single-stranded DNA to form a once adapter ligated nucleic acid strand, the first adapter having a first protruding random sequence that is at least 3 bases long and that acts as a splint to join the single-stranded DNA with the first adpater; (c) ligating a second adapter to a 5′ end of the once adapter ligated nucleic acid strand to form a twice ligated nucleic acid strand, the second adapter having a second protruding random sequence that is at least 3 bases long and that acts as a splint to join the once adapter ligated nucleic acid strand with the second adapter; and (d) performing an amplification reaction on the twice ligated nucleic acid strand, thereby generating copies of the twice ligated nucleic acid strand.