Jason Chin, senior director of bioinformatics at PacBio, talks about using long-read sequence data to generate diploid genome assemblies to produce comprehensive haplotype sequence reconstructions. In the presentation, Chin describes the FALCON Unzip process that combines SNP phasing with the assembly process and allows for determination of the haplotype sequences and identification of structural variants. He presents an example of diploid assembly from inbred Arabidopsis strains.
PacBio CSO Jonas Korlach kicks off the PAG 2017 SMRT Sequencing workshop with acknowledgement of the remarkable work scientists have done with long-read sequencing technology, culminating in more than 2,000 papers so far. Also: Sequel System data, new chemistry and software release, longer libraries, and more.
At PAG 2017, Rockefeller University’s Erich Jarvis offered an in-depth comparison of methods for generating highly contiguous genome assemblies, using hummingbird as the basis to evaluate a number of sequencing and scaffolding technologies. Analyses include gene content, error rate, chromosome metrics, and more. Plus: a long-read look at four genes associated with vocal learning.
At AGBT 2017, the Broad Institute’s Daniel Neafsey reported a large collaborative effort to sequence the mosquito that carries Zika virus. The team is using long-read PacBio sequencing to produce a high-quality genome assembly, which Neafsey expects will replace the 10-year-old Sanger assembly for Aedes aegypti. The new assembly reduces the number of contigs by at least 10-fold, boosts the contig N50 to nearly 2 Mb, and features more complete gene content.
At AGBT 2017, Margaret Roy from Calico Life Sciences discussed a de novo genome sequencing effort for the naked mole rat. This animal has a remarkably long life span and resistance to cancer, both of which make it interesting for studies of life extension. The team is using SMRT Sequencing for a more complete, contiguous assembly than the two existing short-read-based assemblies. Included: data from the Sequel System.
In this PAG 2018 presentation, John Williams of University of Adelaide, presents research on using PacBio SMRT Sequencing to explore the genetic origins of cattle subspecies, Angus (Bos taurus taurus) and Brahman (Bos taurus indicus). He shares RNA sequencing data using the PacBio Iso-Seq method to compare transcriptomes and phase allelic expression and describes how the IsoPhase technique enables evaluation of SNPs through transcriptome mapping back to the single genome of a cross-bred individual. Using a genomic and transcriptomic approach, two high-quality genomes from a single individual and gene isoforms specific to each subspecies are being identified.
In this PAG 2018 presentation, Marty Badgett of PacBio, shares updates on PacBio products and performance. He highlights high-quality genome assembles for Arabidopsis, rice, and maize, the SMRTbell Express Template Prep Kit, SMRT Analysis updates, and the Iso-Seq method for RNA sequencing.
In this PacBio User Group Meeting presentation, Tina Graves-Lindsay of the McDonnell Genome Institute and the Genome Reference Consortium speaks about the importance of phasing human reference genomes. Her team is now working on its fifteenth human genome assembly — part of a major effort to improve genomic representation of ethnic diversity — with a pipeline that generates 60-fold PacBio coverage for a de novo assembly, followed by scaffolding with other technologies. They are also using FALCON-Unzip to separate haplotypes, leading to reference-grade diploid assemblies. This approach has already helped resolve errors seen in other genomes and even the gold-standard…
Jonas Korlach kicks off Day 2 of the 2018 User Group Meeting by discussing a recent collaboration and technique for low-input starting material and high quality de novo assembly projects. While new and not yet fully supported, many researchers have interest in starting with lower amounts of DNA for whole genome sequencing. This protocol requires Express Kit v2, which will be available in early 2019.
This video provides an overview of the techniques and steps of generating a de novo genome assembly with long-read sequencing data generated using PacBio Single Molecule, Real-Time (SMRT) Sequencing. In this video, a PacBio scientist covers the benefits of long reads when generating high-quality genome assemblies, the latest tools for creating assemblies, including HGAP, FALCON and FALCON-Unzip, how to polish and assess the quality of a genome assembly, and how to submit an assembly to NCBI.
This webinar, presented by Nisha Pillai, provides an overview of bioinformatics approaches for PacBio Single Molecule, Real-Time (SMRT) Sequencing data and discusses the whole genome sequencing application including: assembly workflow designs, an overview analysis tools for de novo assembly of SMRT Sequencing data (HGAP4, FALCON & FALCON-Unzip), and finally best practices and case studies.
Tina Graves-Lindsay from the McDonnell Genome Institute reports at AGBT 2020 on how her team is using PacBio sequencing to produce reference-grade human genome assemblies. With highly accurate HiFi reads, no error correction step is needed during the sequencing and analysis process, and they can produce reference-grade assemblies with half the sequence coverage needed before. They are now generating diploid assemblies and will be contributing to the human pangenome reference project.
Vegetatively propagated clones accumulate somatic mutations. The purpose of this study was to better understand the consequences of clonal propagation and involved defining the nature of somatic mutations throughout the genome. Fifteen Zinfandel winegrape clone genomes were sequenced and compared to one another using a highly contiguous genome reference produced from one of the clones, Zinfandel 03. Though most heterozygous variants were shared, somatic mutations accumulated in individual and subsets of clones. Overall, heterozygous mutations were most frequent in intergenic space and more frequent in introns than exons. A significantly larger percentage of CpG, CHG, and CHH sites in repetitive…
Structural variants (SVs) are a largely unexplored feature of plant genomes. Little is known about the type and size of SVs, their distribution among individuals and, especially, their population dynamics. Understanding these dynamics is critical for understanding both the contributions of SVs to phenotypes and the likelihood of identifying them as causal genetic variants in genome-wide associations. Here, we identify SVs and study their evolutionary genomics in clonally propagated grapevine cultivars and their outcrossing wild progenitors. To catalogue SVs, we assembled the highly heterozygous Chardonnay genome, for which one in seven genes is hemizygous based on SVs. Using an integrative…