At DuPont Pioneer, DNA sequencing is paramount for R&D to reveal the genetic basis for traits of interest in commercial crops such as maize, soybean, sorghum, sunflower, alfalfa, canola, wheat, rice, and others. They cannot afford to wait the years it has historically taken for high-quality reference genomes to be produced. Nor can they rely on a single reference to represent the genetic diversity in its germplasm.
In this presentation, Greg Harhay from the USDA offers data on pathogens involved in bovine respiratory disease complex, known as “shipping fever.” His team used PacBio sequencing to analyze several isolates from two different pathogens, looking at their DNA sequence and methylation patterns.
From USDA’s Agricultural Research Service, molecular biologist Sean Gordon discusses the need for long-read sequencing to map an organism’s transcriptome. His team analyzed the wood-decaying fungus Plicaturopsis crispa first with short reads and found that they were missing exons and other important information. They switched to SMRT Sequencing so they could observe, rather than infer, full-length transcripts.
Tim Smith of the USDA presents his work to establish a high-quality reference genome of the San Clemente goat. After generating 70-fold PacBio sequence data, the PacBio assembly proved to be far more complete than the existing draft reference genome, with contigs extending 100 times longer on average.
Tim Smith from the USDA’s Agricultural Research Service talks about using long-read sequencing to redo assemblies for cattle, swine, sheep, and goat. Long-read assemblies correct misassemblies and other problems from older genome projects. Smith says SMRT Sequencing has also made possible isoform sequencing as well as microbiome characterization.
Commentary from PacBio users on their applications of SMRT Sequencing, including Ulf Gyllensten (Uppsala University), Tim Smith (USDA-ARS) and Bobby Sebra (Icahn School of Medicine)
Tim Smith, molecular geneticist at the USDA Agricutural Research Service (ARS) in Clay Center, Nebraska, and director of the U.S. Meat Animal Reseach Center Core Facilities, discusses the USDA’s efforts to improve the goat, swine, cattle, and sheep genomes through long read-based de novoassemblies scaffolded with a variety of approaches. Recent advances in long-read sequencing, combined with new technologies for scaffolding the resulting contigs, have made it possible to make a significant change in the quality of genome assemblies for a very small fraction of the price required to create the originals. Although a change of reference genomes incurs cost,…
Doreen Ware introduces her team’s new assembly of maize, built with PacBio long-read sequencing and genome maps from BioNano Genomics. With a contig N50 of nearly 10 Mb and more complete information than any previous assembly, Ware says, “This is just an amazing time to be a plant scientist.” Her presentation includes a number of highlights from the new assembly, which may help crop improvement efforts for maize.
In this PacBio User Group Meeting presentation, Tim Smith of the USDA’s Agricultural Research Service describes efforts to generate reference-grade genome assemblies for various bovine species and analyze them to understand factors such as how selective breeding has affected certain breeds. Genome assemblies he presents span cattle, water buffalo, and gaur. Smith shows data for each assembly, noting that as data production shifted to the Sequel System, long-read PacBio data became even better at producing highly contiguous assemblies.
In a push to develop insect-based food sources for people, Brenda Oppert from the USDA has been sequencing bug genomes with PacBio technology. Long reads are essential because of the highly repetitive sequences and large genomes. On the Sequel II System, a single SMRT Cell is sufficient to generate 350-fold coverage and produce a high-quality assembly for some of the insects she’s studying.
In this webinar you will hear how several researchers have overcome the challenges of sequencing organisms with small body size using the new low and ultra-low DNA input methods from PacBio. Learn about the advantages of using highly accurate long reads (HiFi reads) to sequence and de novo assemble genomes of single individuals.
Background Assemblies of diploid genomes are generally unphased, pseudo-haploid representations that do not correctly reconstruct the two parental haplotypes present in the individual sequenced. Instead, the assembly alternates between parental haplotypes and may contain duplications in regions where the parental haplotypes are sufficiently different. Trio binning is an approach to genome assembly that uses short reads from both parents to classify long reads from the offspring according to maternal or paternal haplotype origin, and is thus helped rather than impeded by heterozygosity. Using this approach, it is possible to derive two assemblies from an individual, accurately representing both parental contributions…
Orchardgrass (Dactylis glomerata L.) is an important forage grass for cultivating livestock worldwide. Here, we report an ~1.84-Gb chromosome-scale diploid genome assembly of orchardgrass, with a contig N50 of 0.93 Mb, a scaffold N50 of 6.08 Mb and a super-scaffold N50 of 252.52 Mb, which is the first chromosome-scale assembled genome of a cool-season forage grass. The genome includes 40 088 protein-coding genes, and 69% of the assembled sequences are transposable elements, with long terminal repeats (LTRs) being the most abundant. The LTRretrotransposons may have been activated and expanded in the grass genome in response to environmental changes during the Pleistocene between 0 and…
a-Gliadins are a major group of gluten proteins in wheat flour that contribute to the end-use properties for food processing and contain major immunogenic epitopes that can cause serious health-related issues including celiac disease (CD). a-Gliadins are also the youngest group of gluten proteins and are encoded by a large gene family. The majority of the gene family members evolved independently in the A, B, and D genomes of different wheat species after their separation from a common ancestral species. To gain insights into the origin and evolution of these complex genes, the genomic regions of the Gli-2 loci encoding…
The NA1 clonal lineage of Phytophthora ramorum is responsible for Sudden Oak Death, an epidemic that has devastated California’s coastal forest ecosystems. An NA1 isolate Pr102 derived from coast live oak in California was previously sequenced and reported with 65 Mb assembly containing 12 Mb gaps in 2576 scaffolds. Here we report an improved 70 Mb genome in 1512 scaffolds with 6752 bp gaps after incorporating PacBio P5-C3 longreads. This assembly contains 19494 gene models (average gene length 2515 bp) compared to 16134 genes (average gene length of 1673 bp) in the previous version. We predicted 29 new RXLRs and…