DNBSEQ™ Technology
MGI’s DNBSEQ™ technology utilizes DNA Nanoballs (DNBs) for highly accurate sequencing. By circularizing DNA and loading DNBs onto patterned arrays, this system improves sequencing depth and accuracy.
Featuring Combinatorial Probe Anchor Synthesis (cPAS) and advanced imaging, DNBSEQ™ offers reduced duplication rates, enhanced SNP and indel detection, and PCR-free library construction—delivering outstanding performance on platforms such as DNBSEQ-T7.
Advanced Sequencing Precision
MGI’s DNBSEQ™ technology uses DNA Nanoballs (DNBs) for highly accurate and efficient sequencing. DNA is circularized and converted into DNBs, which are loaded onto patterned array chips. Sequencing begins with the addition of a primer, followed by the introduction of fluorescently labelled dNTP probes and DNA polymerase. The system captures images of the DNBs, which are then processed by MGI’s proprietary software to determine the DNA sequence.
Key features include:
- DNA Circularization & DNB Preparation
- Patterned Arrays for high density
- Combinatorial Probe Anchor Synthesis (cPAS)
- Pair-End Sequencing for greater depth
- Advanced Fluidics & Imaging Systems
DNBSEQ™ offers improved sequencing accuracy, reduced duplication rates, and higher SNP and indel detection. Combined with PCR-free library construction, it provides superior performance.
Single-Strand DNA Circularization: To generate single-stranded DNA (ssDNA), double-stranded DNA (dsDNA) with adapter sequences at the ends is denatured. A splint oligonucleotide hybridizes to both the 5′ and 3′ ends of the ssDNA, forming a nicked circle. DNA ligase then repairs the nick, creating a stable single-stranded circle.
DNA Nanoball (DNB) Formation: DNA nanoballs are created via Rolling Circle Amplification (RCA) using the ssDNA circle as a template. RCA amplifies DNA fragments to produce 100 to 1000 copies of the original sequence. The DNB concentration can be easily quantified using Qubit, eliminating the need for expensive quantification instruments.
RCA Advantages: RCA technology uses a high-fidelity DNA polymerase, reducing amplification errors. Unlike PCR, RCA avoids GC biases, dropouts, and the accumulation of errors, significantly improving sequencing accuracy when used with the DNBSEQ™ platform.
Patterned Array Technology: Using a cutting-edge semiconductor manufacturing process, MGI creates patterned binding sites on the surface of a silicon chip. These active spots are evenly spaced, with each site sized to bind only a single DNB (DNA Nanoball). This ensures minimal interference between fluorescence signals from neighboring DNBs, resulting in high sequencing accuracy, optimal chip utilization, and efficient reagent usage.
DNB Loading: DNBs carry a negative charge in acidic conditions due to their phosphate backbone, while the silicon chip surface carries a positive charge. This electrostatic interaction drives the DNBs to bind to the chip surface. Our proprietary loading buffers further stabilize the DNBs, ensuring they remain in place for hundreds of cycles without signal degradation.
The size of each DNB is optimized to match the active spots, ensuring only a single DNB is loaded per site, maximizing effective spot yield and sequencing efficiency.
cPAS Technology: Once sequencing primers bind to the adapter region of the DNB, a fluorescently labelled dNTP probe is incorporated with DNA polymerase. After the incorporation step, any unbound dNTP probes are washed away. The DNB flow cell is then imaged, and the fluorescence signals are converted into digital data. MGI’s proprietary base-calling software processes this data to accurately determine the base sequence. After imaging, a regeneration reagent is applied to remove the fluorescent dye, preparing the DNBs for the next sequencing cycle.
Thanks to advancements in sequencing biochemistry and the identification of a superior sequencing polymerase—screened from tens of thousands of mutants—the sequencing reaction time has been reduced to under one minute, greatly enhancing throughput and efficiency.
2nd Strand Sequencing: After completing the first strand sequencing, 2nd strand generation primers and a polymerase with strand displacement activity are added to begin synthesis of the second strand. The polymerase extends the primer until it reaches the original sequenced strand, displacing it to form a new single-stranded template. This newly generated second strand is optimized to achieve maximum length while staying attached to the original DNB.
Once the second strand sequencing primer binds, the same sequencing chemistry used in first strand sequencing is applied.
This process results in a second strand template with many more copies of the insert DNA, producing a stronger signal and enhanced sequencing accuracy for the second strand.
Base Calling & Quality Scores: Base calls and their quality are determined by analysing signal intensities across all channels. The relationship between signal characteristics and sequencing errors is well-defined through established data models. Predicted sequencing errors for unknown samples are calculated from signal data, with quality scores following the Phred-33 standard.
Sub-Pixel Registration Algorithm: MGI’s proprietary Sub-pixel Registration algorithm extracts image intensity at the sub-pixel level, significantly enhancing base call accuracy.
GPU-Accelerated Data Processing: Our advanced technology leverages GPU-accelerated algorithms, optimizing execution efficiency and enabling real-time image analysis and base calling. This integration has greatly improved both the speed and accuracy of data processing, setting a new industry standard.
Get in Touch
Phone
📞(+86) 4000-688-114
Marketing & PR
MGI_Branding@mgi-tech.com
Careers
MGI_Recruiting@mgi-tech.com
Investor Relations
MGI_IR@mgi-tech.com
