2020-12-19

PacBio

The PacBio Sequel is the latest sequencing instrument developed by Pacific Biosciences. It allows for ultra-long read sequencing, unmatched by other sequencing technologies. Rather than generating small DNA fragments of the Illumina sequence, the Sequel produces reads that span many Kilobases.

The Sequel is therefore the method of choice when characterizing structural variations, repeat regions, pseudogenes and structural variation characterization. Long range sequencing is also the method of choice for de novo sequencing of small genomes, such as micro-organisms.

Advantages:

• Ultra-long reads of up to 60-80 Kb
• Closure of incomplete genome assemblies, especially for polyploids such as vegetables
• Reduced number of contigs and scaffolding due to easy mapping of long reads
• Accurate characterization of large structural variations
• Best option to sequence repeat regions and pseudogenes
• Balanced genome coverage with minimal GC bias

Technology Update
The PacBio Sequel is the follow-up of the RSII. It has increased capacity to 1 million Zero-Mode Waveguides (ZMW’s) compared to 150,000 ZMW’s in the PacBio RS II, delivering a much higher throughput. The technology was plagued by problems, but with the outcome of the version 2 sample prep kits, the issues are resolved. Long-range sequencing using the PacBio Sequel has matured into the most robust method for long-read sequencing. GenomeScan offers the PacBio Sequel as an ISO 17025 accredited service.

Technical specs
PacBio sequencing instruments use the Single Molecule Real-Time (SMRT) technology. This combines the natural process of DNA replication with real-time observation of DNA synthesis.
Zero-Mode Waveguides (ZMWs) allow light to illuminate only the bottom of a well that holds a DNA polymerase/template complex. SMRT cells contain thousands of ZMWs in which the waveguides are monitored simultaneously in real time. The reads are read by the Circular Consensus Sequencing (CCS) technique, in which the same DNA loop is read multiple times.

Custom solutions
We offer custom solutions such as the combination of NovaSeq and PacBio sequencing. This option is ideal for de novo assemblies where the long PacBio reads serve as a reference to align the smaller but more accurate HiSeq reads to. We successfully applied this method for notoriously difficult genomes such as the polyploid genome of the onion.

标签：12,DNA,19,Sequel,long,reads,2020,sequencing,PacBio
来源： https://blog.csdn.net/u010608296/article/details/111407294