55 research outputs found

    The antibody loci of the domestic goat (Capra hircus)

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    The domestic goat (Capra hircus) is an important ruminant species both as a source of antibody-based reagents for research and biomedical applications and as an economically important animal for agriculture, particularly for developing nations that maintain most of the global goat population. Characterization of the loci encoding the goat immune repertoire would be highly beneficial for both vaccine and immune reagent development. However, in goat and other species whose reference genomes were generated using short-read sequencing technologies, the immune loci are poorly assembled as a result of their repetitive nature. Our recent construction of a long-read goat genome assembly (ARS1) has facilitated characterization of all three antibody loci with high confidence and comparative analysis to cattle. We observed broad similarity of goat and cattle antibody-encoding loci but with notable differences that likely influence formation of the functional antibody repertoire. The goat heavy-chain locus is restricted to only four functional and nearly identical IGHV genes, in contrast to the ten observed in cattle. Repertoire analysis indicates that light-chain usage is more balanced in goats, with greater representation of kappa light chains (~ 20-30%) compared to that in cattle (~ 5%). The present study represents the first characterization of the goat antibody loci and will help inform future investigations of their antibody responses to disease and vaccination

    Complete Genome Sequence of Highly Virulent Porcine Reproductive and Respiratory Syndrome Virus Variants That Recently Emerged in the United States

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    A recent outbreak of particularly virulent disease caused by porcine reproductive and respiratory syndrome virus has occurred in swine herds across the United States. We report here the complete genome sequence of eight viral isolates from four Nebraska herds experiencing an outbreak of severe disease in 2016

    Complete Genome Sequences of Two Genotype A2 Small Ruminant Lentiviruses Isolated from Infected U.S. Sheep

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    Two distinct subgroups of genotype A2 small ruminant lentiviruses (SRLVs) have been identified in the United States that infect sheep with specific host trans- membrane protein 154 (TMEM154) diplotypes. Here, we report the first two com- plete genome sequences of SRLV strains infecting U.S. sheep belonging to genotype A2, subgroups 1 and 2

    Classification of small ruminant lentivirus subtype A2, subgroups 1 and 2 based on whole genome comparisons and complex recombination patterns

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    Background: Small ruminant lentiviruses (SRLVs) cause a multisystemic chronic wasting disease in sheep across much of the world. SRLV subtype A2 is prevalent in North America and further classified into multiple subgroups based on variation in the group antigens gene (gag) and envelope (env) genes. In sheep, the ovine transmembrane protein 154 (TMEM154) gene is associated with SRLV susceptibility. Ewes with at least one copy of TMEM154 encoding a fulllength protein with glutamate at position 35 (E35; haplotypes 2 and 3), are highly susceptible to SRLV infection while ewes with any combination of TMEM154 haplotypes which encodes lysine (K35; haplotype 1), or truncated proteins (haplotypes 4 and 6) are several times less so. A2 subgroups 1 and 2 are associated with host TMEM154 genotypes; subgroup 1 with the K35/K35 genotype and subgroup 2 with the E35/E35 genotype. Methods: The goals of this study were to analyze sequence variation within and among SRLV subtype A2 subgroups 1 and 2 and to identify genome-scale recombination patterns. This was done using full-length assemblies of virus samples. Results: Consensus viral genomes were assembled for 23 infected sheep, including animals of assorted TMEM154 genotypes comprised of haplotypes 1, 2, or 3. Viral genome analysis identified viral subgroups 1 and 2 among the samples, and revealed additional substructure within subgroup 2 based on models predicting complex patterns of recombination between the two subgroups in several genomes. Animals with evidence of dual subgroup infection also possessed the most diverse quasi-species and the most highly recombined genomes. Conclusions: The viral subgroup framework developed to classify SRLV consensus genomes along a continuum of recombination suggests that animals with the TMEM154 E35/K35 genotype may represent a reservoir for producing viral genomes representing recombination between A2 subgroups 1 and 2

    Relationship of molecular breeding value for beef tenderness with heifer traits through weaning of their first calf

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    Polymorphisms in μ-calpain (CAPN1) that beneficially associate with beef tenderness are reported to antagonistically associate with calving day in beef heifers and post-partum interval to estrus in beef cows. We, therefore, hypothesized that a molecular breeding value for slice shear force, calculated based on CAPN1 and calpastatin (CAST) genotypes, would demonstrate an antagonistic relationship between genomically predicted slice shear force and ordinal calving date in replacement beef heifers. A secondary objective of this study was to evaluate the association of a polymorphism in diacylglycerol O-acyltransferase (DGAT1) with reproductive traits in beef heifers. One hundred eighty-seven MARC III heifers (¼ Angus, ¼ Hereford, ¼ Red Poll, and ¼ Pinzgauer) that had been selectively bred to increase the frequency of these polymorphisms were submitted for monthly ultrasound exams beginning at 333 d of age and continuing until the start of breeding to determine pubertal status. At the last exam before breeding, all antral follicles were counted, and the length and height of each ovary was measured to determine if genomic selection for slice shear force associated with ovarian follicle number. Calving date, calf gender, and calf birth weight were recorded at parturition. Regression analysis of the molecular breeding value for slice shear force of the heifers on ordinal calving date indicated no association between genomic prediction of tenderness and calving date (P = 0.16); however, there was a tendency for age at puberty to be delayed in heifers as genetic merit for tenderness improved (P = 0.09). The results of the present study indicate that within experimental precision, selecting for tenderness using genomic predictions had minimal or no antagonistic association with reproductive performance in heifers. Further analysis of reproductive performance as cows is needed within this population but applying these genetic markers to select for tenderness in steers does not antagonize reproductive traits influencing conception or first calf birth date and birth weight in replacement beef heifers

    Resolving \u3ci\u3eBovine viral diarrhea virus\u3c/i\u3e subtypes from persistently infected U.S. beef calves with complete genome sequence

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    Bovine viral diarrhea virus (BVDV) is classified into 2 genotypes, BVDV-1 and BVDV-2, each of which contains distinct subtypes with genetic and antigenic variation. To effectively control BVDV by vaccination, it is important to know which subtypes of the virus are circulating and how their prevalence is changing over time. Accordingly, the purpose of our study was to estimate the current prevalence and diversity of BVDV subtypes from persistently infected (PI) beef calves in the central United States. Phylogenetic analysis of the 5′-UTR (5′ untranslated region) for 119 virus strains revealed that a majority (82%) belonged to genotype 1b, and the remaining strains were distributed between genotypes 1a (9%) and 2 (8%); however, BVDV-2 subtypes could not be confidently resolved. Therefore, to better define the variability of U.S. BVDV isolates and further investigate the division of BVDV-2 isolates into subtypes, complete genome sequences were obtained for these isolates as well as representatives of BVDV-1a and -1b. Phylogenetic analyses of the complete coding sequence provided more conclusive genetic classification and revealed that U.S. BVDV-2 isolates belong to at least 3 distinct genetic groups that are statistically supported by both complete and individual coding gene analyses. These results show that a more complex set of BVDV-2 subtypes has been circulating in this region than was previously thought

    Resolving \u3ci\u3eBovine viral diarrhea virus\u3c/i\u3e subtypes from persistently infected U.S. beef calves with complete genome sequence

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    Bovine viral diarrhea virus (BVDV) is classified into 2 genotypes, BVDV-1 and BVDV-2, each of which contains distinct subtypes with genetic and antigenic variation. To effectively control BVDV by vaccination, it is important to know which subtypes of the virus are circulating and how their prevalence is changing over time. Accordingly, the purpose of our study was to estimate the current prevalence and diversity of BVDV subtypes from persistently infected (PI) beef calves in the central United States. Phylogenetic analysis of the 5′-UTR (5′ untranslated region) for 119 virus strains revealed that a majority (82%) belonged to genotype 1b, and the remaining strains were distributed between genotypes 1a (9%) and 2 (8%); however, BVDV-2 subtypes could not be confidently resolved. Therefore, to better define the variability of U.S. BVDV isolates and further investigate the division of BVDV-2 isolates into subtypes, complete genome sequences were obtained for these isolates as well as representatives of BVDV-1a and -1b. Phylogenetic analyses of the complete coding sequence provided more conclusive genetic classification and revealed that U.S. BVDV-2 isolates belong to at least 3 distinct genetic groups that are statistically supported by both complete and individual coding gene analyses. These results show that a more complex set of BVDV-2 subtypes has been circulating in this region than was previously thought

    Whole genomic sequence analysis of \u3ci\u3eBacillus infantis\u3c/i\u3e: defining the genetic blueprint of strain NRRL B-14911, an emerging cardiopathogenic microbe

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    Background: We recently reported the identification of Bacillus sp. NRRL B-14911 that induces heart autoimmunity by generating cardiac-reactive T cells through molecular mimicry. This marine bacterium was originally isolated from the Gulf of Mexico, but no associations with human diseases were reported. Therefore, to characterize its biological and medical significance, we sought to determine and analyze the complete genome sequence of Bacillus sp. NRRL B-14911. Results: Based on the phylogenetic analysis of 16S ribosomal RNA (rRNA) genes, sequence analysis of the 16S-23S rDNA intergenic transcribed spacers, phenotypic microarray, and matrix-assisted laser desorption ionization time-offlight mass spectrometry, we propose that this organism belongs to the species Bacillus infantis, previously shown to be associated with sepsis in a newborn child. Analysis of the complete genome of Bacillus sp. NRRL B-14911 revealed several virulence factors including adhesins, invasins, colonization factors, siderophores and transporters. Likewise, the bacterial genome encodes a wide range of methyl transferases, transporters, enzymatic and biochemical pathways, and insertion sequence elements that are distinct from other closely related bacilli. Conclusions: The complete genome sequence of Bacillus sp. NRRL B-14911 provided in this study may facilitate genetic manipulations to assess gene functions associated with bacterial survival and virulence. Additionally, this bacterium may serve as a useful tool to establish a disease model that permits systematic analysis of autoimmune events in various susceptible rodent strains

    An improved ovine reference genome assembly to facilitate in depth functional annotation of the sheep genome

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    BACKGROUND: The domestic sheep (Ovis aries) is an important agricultural species raised for meat, wool, and milk across the world. A high-quality reference genome for this species enhances the ability to discover genetic mechanisms influencing biological traits. Furthermore, a high-quality reference genome allows for precise functional annotation of gene regulatory elements. The rapid advances in genome assembly algorithms and emergence of sequencing technologies with increasingly long reads provide the opportunity for an improved de novo assembly of the sheep reference genome. FINDINGS: Short-read Illumina (55× coverage), long-read Pacific Biosciences (75× coverage), and Hi-C data from this ewe retrieved from public databases were combined with an additional 50× coverage of Oxford Nanopore data and assembled with canu v1.9. The assembled contigs were scaffolded using Hi-C data with Salsa v2.2, gaps filled with PBsuitev15.8.24, and polished with Nanopolish v0.12.5. After duplicate contig removal with PurgeDups v1.0.1, chromosomes were oriented and polished with 2 rounds of a pipeline that consisted of freebayes v1.3.1 to call variants, Merfin to validate them, and BCFtools to generate the consensus fasta. The ARS-UI_Ramb_v2.0 assembly is 2.63 Gb in length and has improved continuity (contig NG50 of 43.18 Mb), with a 19- and 38-fold decrease in the number of scaffolds compared with Oar_rambouillet_v1.0 and Oar_v4.0. ARS-UI_Ramb_v2.0 has greater per-base accuracy and fewer insertions and deletions identified from mapped RNA sequence than previous assemblies. CONCLUSIONS: The ARS-UI_Ramb_v2.0 assembly is a substantial improvement in contiguity that will optimize the functional annotation of the sheep genome and facilitate improved mapping accuracy of genetic variant and expression data for traits in sheep
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