Mario Caccamo, head of bioinformatics at The Genome Analysis Centre (TGAC) in the UK, integrates many different sequencing technologies to get the best of each for optimal genome assemblies, analysis, and annotation. He uses PacBio’s SMRT Sequencing due to its unique long reads for scaffolding and finishing genomes.
Dick McCombie from Cold Spring Harbor Laboratory describes de novo sequencing of several organisms, including yeast, Arabidopsis, and rice. With SMRT Sequencing, structural differences are preserved and full chromosomes can assemble into single contigs. Longest read observed: 54 kb.
Chongyuan Luo from the Salk Institute for Biological Studies describes sequencing three strains of Arabidopsis thaliana using PacBio technology. The goal: uncover structural variants that have been missed by short-read and other sequencers. Luo notes that PacBio sequencing provides highly accurate SNP detection and also extends the mappability of reads beyond what is possible with short-read data, producing better and more accurate assemblies.
Jason Chin, senior director of bioinformatics at PacBio, talks about using long-read sequence data and string graph assembly for assembling diploid genomes. A major challenge for diploid genome assembly is in distinguishing homologous regions from repeats, so he discusses how long reads are essential for resolving repeat regions. In the presentation, Chin displays data from two inbred Arabidopsis strains used to create a synthetic diploid assembly.
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.
In this AGBT virtual poster video, Jason Chin, a bioinformatician at PacBio, describes a polyploidy-aware de novo assembly approach called FALCON and a new algorithm, dubbed FALCON-unzip, that involves “unzipping” diploid genomes for de novo haplotype reconstructions from SMRT Sequencing data. These methods are illustrated in a studies of fungal, Arabidopsis and human datasets for the resolution of structural variation and characterization of haplotypes.
PacBio Sequencing is characterized by very long sequence reads (averaging > 10,000 bases), lack of GC-bias, and high consensus accuracy. These features have allowed the method to provide a new gold standard in de novo genome assemblies, producing highly contiguous (contig N50 > 1 Mb) and accurate (> QV 50) genome assemblies. We will briefly describe the technology and then highlight the full workflow, from sample preparation through sequencing to data analysis, on examples of insect genome assemblies, and illustrate the difference these high-quality genomes represent with regard to biological insights, compared to fragmented draft assemblies generated by short-read sequencing.
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, Ana Conesa Cegarra from the University of Florida spoke about Iso-Seq analysis tools developed by her group, which created the popular SQANTI tools for Iso-Seq data QC. They’re also working on IsoAnnot to perform functional annotation at isoform resolution; validation has already been done on various species. Currently it’s a set of scripts, but her team is working to produce a more user-friendly version. Finally, tappAS is for functional diversity analysis and for prioritizing genes for validation.
Discover the benefits of HiFi reads and learn how highly accurate long-read sequencing provides a single technology solution across a range of applications.
The widespread occurrence of repetitive stretches of DNA in genomes of organisms across the tree of life imposes fundamental challenges for sequencing, genome assembly, and automated annotation of genes and proteins. This multi-level problem can lead to errors in genome and protein databases that are often not recognized or acknowledged. As a consequence, end users working with sequences with repetitive regions are faced with ‘ready-to-use’ deposited data whose trustworthiness is difficult to determine, let alone to quantify. Here, we provide a review of the problems associated with tandem repeat sequences that originate from different stages during the sequencing-assembly-annotation-deposition workflow, and…
Domestication of clonally propagated crops such as pineapple from South America was hypothesized to be a ‘one-step operation’. We sequenced the genome of Ananas comosus var. bracteatus CB5 and assembled 513?Mb into 25 chromosomes with 29,412 genes. Comparison of the genomes of CB5, F153 and MD2 elucidated the genomic basis of fiber production, color formation, sugar accumulation and fruit maturation. We also resequenced 89 Ananas genomes. Cultivars ‘Smooth Cayenne’ and ‘Queen’ exhibited ancient and recent admixture, while ‘Singapore Spanish’ supported a one-step operation of domestication. We identified 25 selective sweeps, including a strong sweep containing a pair of tandemly duplicated…
Chlorella vulgaris is a fast-growing fresh-water microalga cultivated at the industrial scale for applications ranging from food to biofuel production. To advance our understanding of its biology and to establish genetics tools for biotechnological manipulation, we sequenced the nuclear and organelle genomes of Chlorella vulgaris 211/11P by combining next generation sequencing and optical mapping of isolated DNA molecules. This hybrid approach allowed to assemble the nuclear genome in 14 pseudo-molecules with an N50 of 2.8 Mb and 98.9% of scaffolded genome. The integration of RNA-seq data obtained at two different irradiances of growth (high light-HL versus low light -LL) enabled…
Over the past decade, RNA sequencing (RNA-seq) has become an indispensable tool for transcriptome-wide analysis of differential gene expression and differential splicing of mRNAs. However, as next-generation sequencing technologies have developed, so too has RNA-seq. Now, RNA-seq methods are available for studying many different aspects of RNA biology, including single-cell gene expression, translation (the translatome) and RNA structure (the structurome). Exciting new applications are being explored, such as spatial transcriptomics (spatialomics). Together with new long-read and direct RNA-seq technologies and better computational tools for data analysis, innovations in RNA-seq are contributing to a fuller understanding of RNA biology, from questions…
Forest tree species are increasingly subject to severe mortalities from exotic pests, diseases, and invasive organisms, accelerated by climate change. Forest health issues are threatening multiple species and ecosystem sustainability globally. While sources of resistance may be available in related species, or among surviving trees, introgression of resistance genes into threatened tree species in reasonable time frames requires genome-wide breeding tools. Asian species of chestnut (Castanea spp.) are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of…