Genome Complexity Reduction via Duplex-Specific Nuclease Normalization
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Solution Overview
Problem
Current methods for genotyping human, plant, and animal populations are costly and require large numbers of individuals, necessitating the development of technologies for producing a reduced representation of the genome for sequencing and DNA polymorphism detection.
Innovation Solution
The method involves a two-step PCR process, where the first PCR amplifies genome regions using oligonucleotide primers with specific, degenerate, or universal sequences, followed by normalization with a duplex-specific nuclease, and a second PCR incorporating linker sequences for sequencing, allowing for reduced genome representation and DNA polymorphism detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current genotyping methods are used to analyze large numbers of individuals, then comprehensive genetic relationships and polymorphism detection can be achieved, but the cost increases significantly and the process becomes inefficient
Solution Approach 1:
The method extracts and amplifies only specific genomic regions of interest using targeted PCR with designed primers, rather than analyzing the entire genome. This extraction approach reduces the complexity of the sample while retaining the essential polymorphic regions needed for genotyping, thereby improving throughput without sacrificing detection accuracy
Solution Approach 2:
The genome is segmented into specific amplifiable regions using primer sets that target particular loci. By dividing the genomic analysis into discrete, amplifiable segments, the method enables parallel processing of multiple regions, increasing overall productivity while maintaining comprehensive polymorphism detection coverage
2Loss of information
If the entire genome is analyzed for sequencing and polymorphism detection, then complete genetic information is obtained, but the complexity of the representation increases and costs rise
Solution Approach 1:
The method selectively extracts and amplifies specific genomic regions containing polymorphic sites using targeted PCR. This extraction eliminates the need to analyze the entire genome while preserving all essential genetic information needed for polymorphism detection, thereby reducing representation complexity without information loss
Solution Approach 2:
The method changes the parameter of genomic representation from complete genome coverage to targeted region coverage. By adjusting the scope of analysis to focus only on amplifiable regions with known or predicted polymorphisms, the complexity is reduced while maintaining the critical genetic information required for accurate genotyping
3Productivity
If standard PCR amplification is used without normalization, then amplification is simple and quick, but over-representation of specific fragments occurs reducing sequencing quality
Solution Approach 1:
The method performs preliminary normalization of PCR products before sequencing by treating them with duplex-specific nuclease. This preliminary action balances the representation of different fragments by selectively degrading over-amplified products, ensuring uniform fragment distribution in the final sequencing library without significantly impacting overall amplification efficiency
Solution Approach 2:
A duplex-specific nuclease is introduced as an intermediary enzyme to normalize fragment representation. This mediator selectively degrades over-represented double-stranded DNA fragments while leaving under-represented fragments intact, thereby equalizing the distribution of genomic regions in the amplification product and improving sequencing quality
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 reduces the complexity of the genome representation, minimizing over-representation of specific fragments and enabling efficient sequencing and genotyping, while also allowing for multiplexing of multiple samples, thereby reducing costs and increasing throughput.
Implementation Method 1
normalizing the nucleic acid product of step (a) by contacting it with a duplex-specific nuclease for an effective amount of time to digest the most abundant double-stranded nucleic acid of step (a)
Data Source
AI summary
The present invention provides methods to produce a reduced representation of a genome for sequencing and DNA polymorphism detection. In particular, the invention provides PCR-based methods, with normalization of the amplified products using a duplex-specific nuclease, in order to reduce over-representation of PCR products. Oligonucleotides for use in the disclosed method are also provided.