Scientists at the Gladstone Institutes were early adopters of SMRT Sequencing for transcriptome studies. In a recent study, they used full-length isoform sequence data to overhaul the annotation of the chicken genome, thus providing heart biology researchers with a valuable new reference tool for future studies.
From crop improvement to breeding healthier livestock to modeling human disease, scientists are using PacBio Sequencing to advance understanding of plant and animal genomes. In this article, we look at four examples of plant and animal genome references improved or made possible with SMRT Sequencing, including an early example of transcriptome sequencing of a chicken for improved annotation. These examples highlight insights gained with SMRT Sequencing that are missed with short-read data, such as complex regions or novel genes.
The barn swallow (Hirundo rustica) is a migratory bird that has been the focus of a large number of ecological, behavioral, and genetic studies. To facilitate further population genetics and genomic studies, we present a reference genome assembly for the European subspecies (H. r. rustica).As part of the Genome10K effort on generating high-quality vertebrate genomes (Vertebrate Genomes Project), we have assembled a highly contiguous genome assembly using single molecule real-time (SMRT) DNA sequencing and several Bionano optical map technologies. We compared and integrated optical maps derived from both the Nick, Label, Repair, and Stain technology and from the Direct Label…
More and more eukaryotic genomes are sequenced and assembled, most of them presented as a complete model in which missing chromosomal regions are filled by Ns and where a few chromosomes may be lacking. Avian genomes often contain sequences with high GC content, which has been hypothesized to be at the origin of many missing sequences in these genomes. We investigated features of these missing sequences to discover why some may not have been integrated into genomic libraries and/or sequenced.The sequences of five red jungle fowl cDNA models with high GC content were used as queries to search publicly available…
Our understanding of the pig transcriptome is limited. RNA transcript diversity among nine tissues was assessed using poly(A) selected single-molecule long-read isoform sequencing (Iso-seq) and Illumina RNA sequencing (RNA-seq) from a single White cross-bred pig. Across tissues, a total of 67,746 unique transcripts were observed, including 60.5% predicted protein-coding, 36.2% long non-coding RNA and 3.3% nonsense-mediated decay transcripts. On average, 90% of the splice junctions were supported by RNA-seq within tissue. A large proportion (80%) represented novel transcripts, mostly produced by known protein-coding genes (70%), while 17% corresponded to novel genes. On average, four transcripts per known gene (tpg) were…
Birds are a group with immense availability of genomic resources, and hundreds of forthcoming genomes at the doorstep. We review recent developments in whole genome sequencing, phylogenomics, and comparative genomics of birds. Short read based genome assemblies are common, largely due to efforts of the Bird 10K genome project (B10K). Chromosome-level assemblies are expected to increase due to improved long-read sequencing. The available genomic data has enabled the reconstruction of the bird tree of life with increasing confidence and resolution, but challenges remain in the early splits of Neoaves due to their explosive diversification after the Cretaceous-Paleogene (K-Pg) event. Continued…
Winston Timp from Johns Hopkins University studies the metabolism of hummingbirds, which sustain the highest metabolic rates among all vertebrates. Notably, hummingbirds can switch rapidly between a fuel of lipids to newly ingested sugars. This remarkable metabolism is supported by enzymes which operate at the extreme limit of catalytic efficiency. Understanding the molecular basis of enzymatic action will provide a foundation enabling rational engineering of metabolic circuits in other systems. To do this, Dr. Timp and his team generated a de novo transcriptome of the hummingbird liver using the Iso-Seq method. Characterization of the resulting protein coding sequences provides clues…
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.