As the foundation for scientific discoveries in genetic diversity, sequencing data must be accurate and complete. With highly accurate long-read sequencing, or HiFi sequencing, there is no longer a compromise between read length and accuracy. HiFi sequencing enables some of the highest quality de novo genome assemblies available today as well as comprehensive variant detection in human samples. PacBio HiFi libraries constructed using our standard library workflows require at least 3 µg of DNA input per 1 Gb of genome length, or ~10 µg for a human sample. For some samples it is not possible to extract this amount of…
The Agilent 5200, 5300, and 5400 Fragment Analyzer instruments are fast, high-resolution benchtop capillary electrophoresis (CE) platforms that utilize proprietary markers to accurately size fragments ranging from 10 to 50 kb. This platform allows important DNA quality checkpoints to be completed in one hour for de novo large-genome sequencing projects and other PacBio applications leveraging multi-kilobase read lengths. The instrument can be used in place of time-consuming QC steps involving pulsed field gel electrophoresis (PFGE), saving time by avoiding multiple overnight gel runs when preparing large-insert SMRTbell libraries. Alternative DNA-sizing instruments cannot accurately resolve large DNA fragments in this range.
Obtaining microbial genomes with the highest accuracy and contiguity is extremely important when exploring the functional impact of genetic and epigenetic variants on a genome-wide scale. A comprehensive view of the bacterial genome, including genes, regulatory regions, IS elements, phage integration sites, and base modifications is vital to understanding key traits such as antibiotic resistance, virulence, and metabolism. SMRT Sequencing provides complete genomes, often assembled into a single contig. Our streamlined microbial multiplexing procedure for the Sequel System, from library preparation to genome assembly, can be completed with less than 8 hours bench time. Starting with high-quality genomic DNA (gDNA),…
The Agilent Femto Pulse system automated pulsed-field CE instrument is a fast, high-resolution benchtop capillary electrophoresis (CE) platform that utilizes pulsed-field electrophoresis to separate high molecular weight DNA fragments. This platform allows important DNA quality checkpoints to be completed in less than 1.5 hours with minimal sample input for de novo large genome sequencing projects and other PacBio applications leveraging multi-kilobase read lengths. The instrument can be used in place of gel-based pulsed-field electrophoresis (PFGE) systems to fully support generation of large-insert SMRTbell libraries with accurate sizing to 165 kb. Alternative DNA sizing instruments cannot accurately resolve large DNA fragments…
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…
Haplotype phasing of genetic variants is important for interpretation of the maize genome, population genetic analysis, and functional genomic analysis of allelic activity. Accordingly, accurate methods for phasing full-length isoforms are essential for functional genomics study. In this study, we performed an isoform-level phasing study in maize, using two inbred lines and their reciprocal crosses, based on single-molecule full-length cDNA sequencing. To phase and analyze full-length transcripts between hybrids and parents, we developed a tool called IsoPhase. Using this tool, we validated the majority of SNPs called against matching short read data and identified cases of allele-specific, gene-level, and isoform-level…
The antimicrobial resistance (AMR) crisis represents a serious threat to public health and has resulted in concentrated efforts to accelerate development of rapid molecular diagnostics for AMR. In combination with publicly-available web-based AMR databases, whole genome sequencing (WGS) offers the capacity for rapid detection of antibiotic resistance genes. Here we studied the concordance between WGS-based resistance prediction and phenotypic susceptibility testing results for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus (VRE) clinical isolates using publicly-available tools and databases.Clinical isolates prospectively collected at the University of Pittsburgh Medical Center between December 2016 and December 2017 underwent WGS. Antibiotic resistance gene…
Haplotype-resolved genome assemblies are important for understanding how combinations of variants impact phenotypes. These assemblies can be created in various ways, such as use of tissues that contain single-haplotype (haploid) genomes, or by co-sequencing of parental genomes, but these approaches can be impractical in many situations. We present FALCON-Phase, which integrates long-read sequencing data and ultra-long-range Hi-C chromatin interaction data of a diploid individual to create high-quality, phased diploid genome assemblies. The method was evaluated by application to three datasets, including human, cattle, and zebra finch, for which high-quality, fully haplotype resolved assemblies were available for benchmarking. Phasing algorithm accuracy…
Pepper is an important vegetable with great economic value and unique biological features. In the past few years, significant development has been made towards understanding the huge complex pepper genome; however, pepper functional genomics has not been well studied. To better understand the pepper gene structure and pepper gene regulation, we conducted full-length mRNA sequencing by PacBio sequencing and obtained 57862 high-quality full-length mRNA sequences derived from 18362 previously annotated and 5769 newly detected genes. New gene models were built that combined the full-length mRNA sequences and corrected approximately 500 fragmented gene models from previous annotations. Based on the full-length…
The soft tick Argas japonicus mainly infests birds and can cause human dermatitis; however, no pathogen has been identified from this tick species in China. In the present study, the microbiota in A. japonicus collected from an epidemic community was explored, and some putative Rickettsia pathogens were further characterized. The results obtained indicated that bacteria in A. japonicus were mainly ascribed to the phyla Proteobacteria, Firmicutes and Actinobacteria. At the genus level, the male A. japonicus harboured more diverse bacteria than the females and nymphs. The bacteria Alcaligenes, Pseudomonas, Rickettsia and Staphylococcus were common in nymphs and adults. The abundance…
DNA transformation and homology-based transcriptional silencing are frequently used to assess gene function in Phytophthora. Since unplanned side-effects of these tools are not well-characterized, we used P. infestans to study plasmid integration sites and whether knockdowns caused by homology-dependent silencing spreads to other genes. Insertions occurred both in gene-dense and gene-sparse regions but disproportionately near the 5′ ends of genes, which disrupted native coding sequences. Microhomology at the recombination site between plasmid and chromosome was common. Studies of transformants silenced for twelve different gene targets indicated that neighbors within 500-nt were often co-silenced, regardless of whether hairpin or sense constructs…
Schistosomes cause schistosomiasis, the worldtextquoterights second most important parasitic disease after malaria. A peculiar feature of schistosomes is their ability to produce viable and fertile hybrids. Originally only present in the tropics, schistosomiasis is now also endemic in Europe. Based on two genetic markers the European species had been identified as a hybrid between the ruminant-infective Schistosoma bovis and the human-infective Schistosoma haematobium.Here we describe for the first time the genomic composition of the European schistosome hybrid (77% of S. haematobium and 23% of S. bovis origins), its morphometric parameters and its compatibility with the European vector snail and intermediate…
The evolution and global transmission of antimicrobial resistance has been well documented in Gram-negative bacteria and healthcare-associated epidemic pathogens, often emerging from regions with heavy antimicrobial use. However, the degree to which similar processes occur with Gram-positive bacteria in the community setting is less well understood. Here, we trace the recent origins and global spread of a multidrug resistant, community-associated Staphylococcus aureus lineage from the Indian subcontinent, the Bengal Bay clone (ST772). We generated whole genome sequence data of 340 isolates from 14 countries, including the first isolates from Bangladesh and India, to reconstruct the evolutionary history and genomic epidemiology…
Background: Salmonella Typhimurium ST313 exhibits signatures of adaptation to invasive human infection, including higher resistance to humoral immune responses than gastrointestinal isolates. Full resistance to antibody-mediated complement killing (serum resistance) among nontyphoidal Salmonellae is uncommon, but selection of highly resistant strains could compromise vaccine-induced antibody immunity. Here, we address the hypothesis that serum resistance is due to a distinct genotype or transcriptome response in S. Typhimurium ST313.