Transposase-Mediated Single-Molecule Sequencing for Low-Input DNA
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Solution Overview
Problem
Current single-molecule sequencing technologies require high input DNA amounts due to sample losses during mechanical or enzymatic fragmentation and serial reaction cleanups, limiting their application to genome assembly and medical genetics, and precluding analysis of rare clinical samples and microorganisms.
Innovation Solution
The implementation of tagmentation using a hyperactive transposase to generate nucleic acid libraries from as little as 10 ng to 100 ng of DNA, eliminating the need for PCR amplification and reducing input requirements by 90-99%, while controlling fragment size and incorporating unique barcodes for multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical or enzymatic fragmentation and serial reaction cleanups are used for library preparation, then sequencing accuracy is improved, but input DNA requirements increase significantly (1-5 μg)
Solution Approach 1:
The invention extracts and eliminates the PCR amplification step from the library preparation workflow. By using transposase-based tagmentation that directly generates sequencing-ready libraries without requiring amplification, the method removes a entire process stage that consumes time and resources, thereby reducing input DNA requirements while maintaining sequencing accuracy.
Solution Approach 2:
The invention introduces transposase as an intermediary enzyme that directly inserts adapters into fragmented DNA without requiring PCR amplification. This intermediary mechanism allows for efficient library preparation from low-input samples by mediating the conversion of fragmented DNA to sequencing libraries in a single step, bypassing the need for exponential amplification.
2Quantity of substance
If PCR amplification is used to reduce input DNA requirements, then input DNA amount is reduced, but modified bases are erased and biases are introduced
Solution Approach 1:
The invention extracts and eliminates the PCR amplification step from the library preparation workflow. By using transposase-based tagmentation that directly generates sequencing-ready libraries without requiring amplification, the method removes a entire process stage that consumes time and resources, thereby reducing input DNA requirements while maintaining sequencing accuracy.
Solution Approach 2:
The transposase-based tagmentation method is self-sufficient in generating sequencing libraries directly from fragmented DNA without requiring external amplification assistance. The transposase enzyme autonomously performs adapter insertion and library construction in a single reaction, eliminating the need for PCR amplification and preserving native DNA modifications.
3Quantity of substance
If transposase tagmentation is used to reduce input DNA requirements, then input DNA amount is reduced by 90-99%, but fragment size control and library quality may be compromised
Solution Approach 1:
The invention employs dynamics by making the transposase reaction conditions adjustable and optimizable. By varying transposase concentration, reaction time, temperature, and DNA fragmentation parameters, the method dynamically controls fragment size distribution to achieve optimal library preparation from low-input samples while maintaining sequencing quality.
Solution Approach 2:
The invention applies parameter changes by systematically optimizing transposase concentration, reaction temperature, incubation time, and DNA fragmentation conditions. These parameter adjustments enable precise control over fragment size distribution and library quality, allowing the method to work effectively with as little as 10-100 ng of input DNA while maintaining manufacturing precision.
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
Enables sensitive, scalable, and cellularly resolved single-molecule genomics by accurately detecting genetic and epigenetic variants from low-input samples, including rare clinical samples, with high-throughput sequencing and concurrent chromatin structure mapping.
Implementation Method 1
conducting a tagmentation reaction with a hyperactive transposase on the isolated DNA sequences cells or nuclei to produce a plurality of nucleic acid libraries
Data Source
AI summary
Methods are provided that implement tagmentation for single-molecule sequencing use 90-99% less input than current protocols: SMRT-Tag, which allows detection of genetic variation and CpG methylation, and SAMOSA-Tag, which uses exogenous adenine methylation to add a third channel for probing chromatin accessibility. SAMOSA-Tag of 30,000-50,000 nuclei resolved single-fiber chromatin structure, CTCF binding, and DNA methylation in patient-derived prostate cancer xenografts and uncovered metastasis-associated global epigenome disorganization.