The domestic pig (Sus scrofa) is important both as a food source and as a biomedical model with high anatomical and immunological similarity to humans. The draft reference genome (Sscrofa10.2) represented a purebred female pig from a commercial pork production breed (Duroc), and was established using older clone-based sequencing methods. The Sscrofa10.2 assembly was incomplete and unresolved redundancies, short range order and orientation errors and associated misassembled genes limited its utility. We present two highly contiguous chromosome-level genome assemblies created with more recent long read technologies and a whole genome shotgun strategy, one for the same Duroc female (Sscrofa11.1) and…
Alan Archibald compares two new de novo PacBio pig genome assemblies to a previously released draft genome, finding significant improvement that could be important for breeding programs. In one example, he shows chromosome 1, which was split into more than 9,000 contigs in the draft genome, is now represented in just 10 contigs.
Many applications of high throughput sequencing rely on the availability of an accurate reference genome. Errors in the reference genome assembly increase the number of false-positives in downstream analyses. Recently, we have shown that over 33% of the current pig reference genome, Sscrofa10.2, is either misassembled or otherwise unreliable for genomic analyses. Additionally, ~10% of the bases in the assembly are Ns in gaps of an arbitrary size. Thousands of highly fragmented contigs remain unplaced and many genes are known to be missing from the assembly. Here we present a new assembly of the pig genome, Sscrofa11, assembled using 65X…
Despite the significance of chicken as a model organism, our understanding of the chicken transcriptome is limited compared to human. This issue is common to all non-human vertebrate annotations due to the difficulty in transcript identification from short read RNAseq data. While previous studies have used single molecule long read sequencing for transcript discovery, they did not perform RNA normalization and 5′-cap selection which may have resulted in lower transcriptome coverage and truncated transcript sequences.We sequenced normalised chicken brain and embryo RNA libraries with Pacific Bioscience Iso-Seq. 5′ cap selection was performed on the embryo library to provide methodological comparison.…
The domestic chicken (Gallus gallus) is widely used as a model in developmental biology and is also an important livestock species. We describe a novel approach to data integration to generate an mRNA expression atlas for the chicken spanning major tissue types and developmental stages, using a diverse range of publicly-archived RNA-seq datasets and new data derived from immune cells and tissues.Randomly down-sampling RNA-seq datasets to a common depth and quantifying expression against a reference transcriptome using the mRNA quantitation tool Kallisto ensured that disparate datasets explored comparable transcriptomic space. The network analysis tool Graphia was used to extract clusters…
The purpose of this study was to determine the plasmid architecture and context of resistance genes in multi-drug resistant (MDR) Escherichia coli strains isolated from urinary tract infections in dogs. Illumina and single-molecule real-time (SMRT) sequencing were applied to assemble the complete genomes of E. coli strains associated with clinical urinary tract infections, which were either phenotypically MDR or drug susceptible. This revealed that multiple distinct families of plasmids were associated with building an MDR phenotype. Plasmid-mediated AmpC (CMY-2) beta-lactamase resistance was associated with a clonal group of IncI1 plasmids that has remained stable in isolates collected up to a…