Valerie Schneider of the National Center for Biotechnology Information discuss how the Genome Reference Consortium (GRC) is bringing more ethnic diversity to the latest human reference assembly (GRCh38) by adding patches and alternate loci scaffolds. Scientists working with population graphs are among the early adopters of these new alternate loci scaffolds. She also discusses work underway at the McDonnell Genome Institute at Washington University to generate a set of high-quality, de novo whole genomes from a wide variety of populations. The new ethnic genomes “are also intended to stand on their own as complements to the reference so users can…
In this ASHG 2016 virtual poster, Flora Tassone from UC Davis describes her study of the molecular mechanisms linked to fragile X syndrome and associated disorders, such as FXTAS. She is using SMRT Sequencing to resolve the FMR1 gene in premutation carriers because it’s the only technology that can generate full-length transcripts with the causative CGG repeat expansion. Plus: direct confirmation of predicted isoform configurations.
Euan Ashley from Stanford University started with the premise that while current efforts in the field of genomics medicine address 30% of patient cases, there’s a need for new approaches to make sense of the remaining 70%. Toward that end, he said that accurately calling structural variants is a major need. In one translational research example, Ashley said that SMRT Sequencing with the Sequel System allowed his team to identify six potentially causative genes in an individual with complex and varied symptoms; one gene was associated with Carney syndrome, which was a match for the person’s physiology and was later…
In this AGBT 2017 talk, PacBio CSO Jonas Korlach provided a technology roadmap for the Sequel System, including plans the continue performance and throughput increases through early 2019. Per SMRT Cell throughput of the Sequel System is expected to double this year and again next year. Together with a new higher-capacity SMRT Cell expected to be released by the end of 2018, these improvements result in a ~30-fold increase or ~150 Gb / SMRT Cell allowing a real $1000 real de novo human genome assembly. Also discussed: Additional application protocol improvements, new chemistry and software updates, and a look at…
SMRT Sequencing is a DNA sequencing technology characterized by long read lengths and high consensus accuracy, regardless of the sequence complexity or GC content of the DNA sample. These characteristics can be harnessed to address medically relevant genes, mRNA transcripts, and other genomic features that are otherwise difficult or impossible to resolve. I will describe examples for such new clinical research in diverse areas, including full-length gene sequencing with allelic haplotype phasing, gene/pseudogene discrimination, sequencing extreme DNA contexts, high-resolution pharmacogenomics, biomarker discovery, structural variant resolution, full-length mRNA isoform cataloging, and direct methylation detection.
To start Day 1 of the PacBio User Group Meeting, Jonas Korlach, PacBio CSO, provides an update on the latest releases and performance metrics for the Sequel II System. The longest reads generated on this system with the SMRT Cell 8M now go beyond 175,000 bases, while maintaining extremely high accuracy. HiFi mode, for example, uses circular consensus sequencing to achieve accuracy of Q40 or even Q50.
In this PacBio User Group Meeting presentation, PacBio scientist Kristin Mars speaks about recent updates, such as the single-day library prep that’s now possible with the Iso-Seq Express workflow. She also notes that one SMRT Cell 8M is sufficient for most Iso-Seq experiments for whole transcriptome sequencing at an affordable price.
In this webinar, Dr. Ashby gives attendees a brief update on PacBio’s metagenomics solutions on the Sequel II System. Then, Dr. Ma, University of Maryland School of Medicine, discusses her work using long read sequencing to identify high-resolution microbial biomarkers associated with leaky gut syndrome in premature infants. Finally, Dr. Weinstock, The Jackson Laboratory, talks about the potential of highly accurate long reads to enable strain-level resolution of the human gut microbiome by resolving intraspecies variation in multiple copies of the 16S gene.
Dr. Wenger gives attendees an update on PacBio’s long-read sequencing and variant detection capabilities on the Sequel II System and shares recommendations on how to design your own study using HiFi reads. Then, Dr. Sund from Cincinnati Children’s Hospital Medical Center describes how she has used long-read sequencing to solve rare neurological diseases involving complex structural rearrangements that were previously unsolved with standard methods.
PacBio 2014 User Group Meeting Presentation Slides: Alisha Holloway of the Gladstone Institutes presented on the use of isoform sequencing (Iso-Seq) to improve the annotation of the chicken genome as a model reference for cardiovascular research.
Alternative splicing of RNA is an important mechanism that increases protein diversity and is pervasive in the most complex biological functions. While advances in RNA sequencing methods have accelerated our understanding of the transcriptome, isoform discovery remains computationally challenging due to short read lengths. Here, we describe the Isoform Sequencing (Iso-Seq) method using long reads generated by the PacBio RS II. We sequenced rat heart and lung RNA using the Clontech® SMARTer® cDNA preparation kit followed by size selection using agarose gel. Additionally, we tested the BluePippin™ device from Sage Science for efficiently extracting longer transcripts = 3 kb. Post-sequencing,…
The majority of human genes are alternatively spliced, making it possible for most genes to generate multiple proteins. The process of alternative splicing is highly regulated in a developmental-stage and tissue-specific manner. Perturbations in the regulation of these events can lead to disease in humans. Alternative splicing has been shown to play a role in human cancer, muscular dystrophy, Alzheimer’s, and many other diseases. Understanding these diseases requires knowing the full complement of mRNA isoforms. Microarrays and high-throughput cDNA sequencing have become highly successful tools for studying transcriptomes, however these technologies only provide small fragments of transcripts and building complete…
While the identification of individual SNPs has been readily available for some time, the ability to accurately phase SNPs and structural variation across a haplotype has been a challenge. With individual reads of an average length of 9 kb (P5-C3), and individual reads beyond 30 kb in length, SMRT Sequencing technology allows the identification of mutation combinations such as microdeletions, insertions, and substitutions without any predetermined reference sequence. Long- amplicon analysis is a novel protocol that identifies and reports the abundance of differing clusters of sequencing reads within a single library. Graphs generated via hierarchical clustering of individual sequencing reads…
Single Molecule, Real-Time (SMRT) Sequencing holds promise for addressing new frontiers in large genome complexities, such as long, highly repetitive, low-complexity regions and duplication events, and differentiating between transcript isoforms that are difficult to resolve with short-read technologies. We present solutions available for both reference genome improvement (>100 MB) and transcriptome research to best leverage long reads that have exceeded 20 Kb in length. Benefits for these applications are further realized with consistent use of size-selection of input sample using the BluePippin™ device from Sage Science. Highlights from our genome assembly projects using the latest P5-C3 chemistry on model organisms…
Advances in RNA sequencing have accelerated our understanding of the transcriptome, however isoform discovery remains challenging due to short read lengths. The Iso-Seq Application provides a new alternative to sequence full-length cDNA libraries using long reads from the PacBio RS II. Identification of long and often rare isoforms is demonstrated with rat heart and lung RNA prepared using the Clontech® SMARTer® cDNA preparation kit, followed by agarose-gel size selection in fractions of 1-2 kb, 2-3 kb and 3-6 kb. For each tissue, 1.8 and 1.2 million reads were obtained from 32 and 26 SMRT Cells, respectively. Filtering for reads with…