Topic:Genes
Genes in horses are segments of DNA that encode the biological instructions necessary for the development, functioning, and reproduction of equine species. These genetic sequences influence a wide range of traits, including coat color, speed, endurance, and susceptibility to diseases. Genetic research in horses focuses on identifying specific genes and genetic markers associated with these traits, as well as understanding the inheritance patterns and genetic diversity within and between horse breeds. Studies in equine genetics contribute to breeding programs, disease prevention strategies, and the overall understanding of horse biology. This page compiles peer-reviewed research studies and scholarly articles that explore the identification, function, and implications of genes in equine health and performance.
In vivo expression of and cell-mediated immune responses to the plasmid-encoded virulence-associated proteins of Rhodococcus equi in foals. Rhodococcus equi is a facultative intracellular pathogen that causes pneumonia in foals but does not induce disease in adult horses. Virulence of R. equi depends on the presence of a large plasmid, which encodes a family of seven virulence-associated proteins (VapA and VapC to VapH). Eradication of R. equi from the lungs depends on gamma interferon (IFN-gamma) production by T lymphocytes. The objectives of the present study were to determine the relative in vivo expression of the vap genes of R. equi in the lungs of infected foals, to determine the recall response of bronchial lymph node (BLN)...
Identifying the future needs for long-term USDA efforts in agricultural animal genomics. Agricultural animal research has been immensely successful over the past century in developing technology and methodologies that have dramatically enhanced production efficiency of the beef, dairy, swine, poultry, sheep, and aquaculture industries. In the past two decades, molecular biology has changed the face of agricultural animal research, primarily in the arena of genomics and the relatively new offshoot areas of functional genomics, proteomics, transcriptomics, metabolomics and metagenomics. Publication of genetic and physical genome maps in the past 15 years has given rise to the possib...
Genetic typing of equine arteritis virus isolates from Argentina. We report the nucleotide sequence and genetic diversity of four Equine Arteritis Virus (EAV) ORF 5 and 6 from Argentina isolates, obtained from asymptomatic virus-shedding stallions. Nucleic acid recovered from the isolates were amplified by RT-PCR and sequenced. Nucleotide and deduced amino acid sequences from the Argentine isolates were compared with 17 sequences available from the GenBank. Phylogenetic analysis revealed that the Argentine isolates grouped together in a definite cluster near European strains. Despite the greater genetic variability among ORF 5 from different isolates and str...
Multiplex real-time PCR for the detection and differentiation of equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4). A multiplex real-time PCR was designed to detect and differentiate equid herpesvirus 1 (EHV-1) and equid herpesvirus 4 (EHV-4). The PCR targets the glycoprotein B gene of EHV-1 and EHV-4. Primers and probes were specific to each equine herpesvirus type and can be used in monoplex or multiplex PCRs, allowing the differentiation of these two closely related members of the Alphaherpesvirinae. The two probes were minor-groove binding probes (MGB) labelled with 6-carboxy-fluorescein (FAM) and VIC for detection of EHV-1 and EHV-4, respectively. Ten EHV-1 isolates, six EHV-1 positive clinical samples...
Two SNPs in the SILV gene are associated with silver coat colour in ponies. In horses, a pigment dilution acting only on black eumelanin is the so-called silver coat colour, which is characterized by a chocolate-to-reddish body with a white mane and tail. Using information from other species, we focused our study on SILV as a possible candidate gene for the equine silver phenotype. A 1559-bp genomic fragment was sequenced in 24 horses, and five SNPs were detected. Two of the five SNPs (DQ665301:g.697A>T and DQ665301:g.1457C>T) were genotyped in 112 horses representing eight colour phenotypes. Both mutations were completely associated with the silver phenotype: all eum...
Molecular characterization of tumor necrosis alpha-induced protein 6 and its human chorionic gonadotropin-dependent induction in theca and mural granulosa cells of equine preovulatory follicles. The preovulatory rise in gonadotropins causes an expansion of the cumulus-oocyte complex, a process requiring the induction of several genes. The objectives of this study were to clone the equine tumor necrosis factor alpha-induced protein 6 (TNFAIP6), and investigate its regulation in equine follicles during human chorionic gonadotropin (hCG)-induced ovulation. The isolation of the equine TNFAIP6 cDNA revealed that it contains an open reading frame of 834 bp (including the stop codon), encoding a predicted 277 amino acid protein that is highly similar (91-93% identity) to known mammalian homo...
Neonatal growth cartilage: equine tissue specific gene expression. Endochondral bone formation is an important process in development and growth of the skeleton; still many of the mechanisms of growth cartilage remain unknown. The aim of this study was to identify genes specifically expressed in growth cartilage by constructing a subtraction cDNA library of the articular-epiphyseal cartilage complex from neonatal foal. Two hundred and eighty-four differently expressed clones, representing five novel and 37 known genes, were detected by subtraction hybridization. The tissue specificity of these genes was verified by reverse Northern analysis, and tissue distri...
Lactoferrin, a glycoprotein with immunomodulatory and mast cell stabilising properties, in skin of horses suffering from Culicoides hypersensitivity. Lactoferrin (LF), a glycogen of the transferrin family with anti-bacterial and immunomodulatory properties, is expressed in various secretions and tissues. Cutaneous LF serves as a mast cell stabilising compound, modulates T cell activity and is found during IgE-mediated late phase reactions at allergen challenged sites. Culicoides hypersensitivity (CHS) in horses is a common IgE-mediated allergic dermatitis, characterised by an early and late phase cutaneous reaction upon allergen challenge. The aim of the study presented here was to examine whether LF mRNA expression in skin biopsies from ho...
Improved resolution of the comparative horse-human map: investigating markers with in silico and linkage mapping approaches. Genetic maps are extremely important tools for tracing the genes that govern economically significant traits, and microsatellites are a significant component of these. In this study, we isolated 2346 novel horse microsatellites as resources for the construction of high-density horse genetic maps. Of these 2346 markers, 339 (14.5%) horse sequences showed sequence homology to DNA sequences in the human genome, demonstrating that microsatellites as type II markers are valuable resources for developing linkage maps and that they have a potential equal to that of type I markers for developing compa...
Expression of cyclooxygenase-1 and -2 in naturally occurring squamous cell carcinomas in horses. To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses. Methods: Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia. Methods: Tissue samples were snap frozen in liquid nitrogen and stored at -80 degrees C until analysis. Protein was extracted from the frozen tissues,...
Mutation and virulence assessment of chromosomal genes of Rhodococcus equi 103. Rhodococcus equi can cause severe or fatal pneumonia in foals as well as in immunocompromised animals and humans. Its ability to persist in macrophages is fundamental to how it causes disease, but the basis of this is poorly understood. To examine further the general application of a recently developed system of targeted gene mutation and to assess the importance of different genes in resistance to innate immune defenses, we disrupted the genes encoding high-temperature requirement A (htrA), nitrate reductase (narG), peptidase D (pepD), phosphoribosylaminoimidazole-succinocarboxamide synthase ...
Acute systemic inflammation transiently synchronizes clock gene expression in equine peripheral blood. Peripheral clocks receive timing signals from the master mammalian pacemaker in the suprachiasmatic nucleus (SCN) and function to adaptively anticipate daily changes that influence local physiology. Evidence suggests that peripheral immune activation may act as a resetting signal for circadian clocks in peripheral tissues. We wished to investigate whether acute systemic inflammation could synchronize clock gene expression in equine peripheral blood, a tissue that does not normally oscillate in this species. We report that in vivo administration of lipopolysaccharide (LPS) results in significan...
Detection of bovine papillomavirus type 1 genomes and viral gene expression in equine inflammatory skin conditions. Papillomaviruses are normally strictly species-specific and even under experimental conditions do not usually infect any other host than the natural host. The only documented reports of natural papillomavirus cross-species infection are of BPV-1/BPV-2, which can infect horses and induce equine sarcoids. BPV DNA has not been detected in non-sarcoid equine tumours or equine papillomas, but its presence has been reported in some cases of equine dermatitis. In the present study, we show that equine inflammatory skin conditions harbour episomal circular double stranded BPV-1 genomes, with copy numb...
Diversity in Indian equine rotaviruses: identification of genotype G10,P6[1] and G1 strains and a new VP7 genotype (G16) strain in specimens from diarrheic foals in India. Rotaviruses causing severe diarrhea in foals in two organized farms in northern India, during the period from 2003 to 2005, were characterized by electropherotyping, serotyping, and sequence analysis of the genes encoding the outer capsid proteins. Of 137 specimens, 47 (34.31%) were positive for rotavirus and exhibited at least five different electropherotypes (E), E1 to E5. Strains belonging to different electropherotypes exhibited either a different serotype/genotype specificity or a lack of reactivity to typing monoclonal antibodies (MAbs) used in this study. Strains belonging to E1, E2, an...
Analysis of peripheral blood mononuclear cells gene expression in endurance horses by cDNA-AFLP technique. The knowledge of molecular mechanisms of stress response in athlete horses can allow us to plan an appropriate and high-grade training to obtain better performance and to preserve horse welfare. It is well known that excessive muscular exercise can lead to a number of responses which may be associated with modification of the mRNA levels for a number of metabolic genes such as those involved in the immune response. In the present study cDNA-AFLP technique was applied to Arab endurance horses under stressing conditions to visualise variations of transcriptional profiles; 49 transcript derived f...
Differential expression of calcineurin and SR Ca2+ handling proteins in equine muscle fibers during early postnatal growth. During early postnatal development, the myosin heavy chain (MyHC) expression pattern in equine gluteus medius muscle shows adaptation to movement and load,resulting in a decrease in the number of fast MyHC fibers and an increase in the number of slow MyHC fibers. In the present study we correlated the expression of MyHC isoforms to the expression of sarcoplasmic(endo)reticulum Ca2+-ATPase 1 and 2a (SERCA), phospholamban (PLB), calcineurin A (CnA), and calcineurin B (CnB). Gluteus medius muscle biopsies were taken at 0, 2, 4, and 48 weeks and analyzed using immunofluorescence. Both SERCA isofor...
Strategies for construction of luteinizing hormone beta subunit analogs with carboxyl terminal extensions in non-primate, non-equid mammalian species. Chorionic gonadotropins (CG) are unique because they have a carboxyl terminal peptide (CTP) extension on their beta subunits that prolongs circulatory survival. CGbeta genes from the human being and horse have evolved from ancestral luteinizing hormone (LH) beta genes by different pathways that involve deletions that change the reading frames and yield a CTP. Here we further review our previous analysis, aimed at determining whether LHbeta genes in non-primate, non-equid species inherently possess DNA sequences that encode CTP-like domains. In multiple mammalian species, simple frame-shift mut...
Molecular characterization of the equine collagen, type IX, alpha 2 (COL9A2) gene on horse chromosome 2p16–>p15. The mammalian collagen, type IX, alpha 2 gene (COL9A2) encodes the alpha-2 chain of type IX collagen and is located on horse chromosome 2p16-->p14 harbouring a quantitative trait locus for osteochondrosis. We isolated a bacterial artificial chromosome (BAC) clone containing the equine COL9A2 gene and determined the complete genomic sequence of this gene. Cloning and characterization of equine COL9A2 revealed that the equine gene consists of 32 exons spanning approximately 15 kb. The COL9A2 transcript encodes a single protein of 688 amino acids. Thirty two single nucleotide polymorphisms (SNPs)...
A missense mutation in PMEL17 is associated with the Silver coat color in the horse. The Silver coat color, also called Silver dapple, in the horse is characterized by dilution of the black pigment in the hair. This phenotype shows an autosomal dominant inheritance. The effect of the mutation is most visible in the long hairs of the mane and tail, which are diluted to a mixture of white and gray hairs. Herein we describe the identification of the responsible gene and a missense mutation associated with the Silver phenotype. Results: Segregation data on the Silver locus (Z) were obtained within one half-sib family that consisted of a heterozygous Silver colored stallion with 34...
Presence of natural anti-Galalpha1-4GalNAcbeta1-3Gal (anti-NOR) antibodies in animal sera. Rare polyagglutinable NOR erythrocytes contain unusual globoside extention products terminating with a Galalpha1-4GalNAcbeta1-3Gal- unit. This trisaccharide epitope is recognized by recently characterized antibodies naturally occurring in most human sera (Duk et al., Glycobiology, 15, 109, 2005). These antibodies represent two major types of fine specificity. All these antibodies are most strongly inhibited by Galalpha1-4GalNAcbeta1-3Gal (NOR-tri), and weakly by Galalpha1-4Gal. However, the type 1 antibodies are strongly inhibited by Galalpha1-4Galbeta1-3Gal-R and weakly by Galalpha1-4GalNAc, ...
Microbial source tracking by DNA sequence analysis of the Escherichia coli malate dehydrogenase gene. Criteria for sub-typing of microbial organisms by DNA sequencing proposed by Olive and Bean were applied to several genes in Escherichia coli to identify targets for the development of microbial source tracking assays. Based on the aforementioned criteria, the icd (isocitrate dehydrogenase), and putP (proline permease) genes were excluded as potential targets due to their high rates of horizontal gene transfer; the rrs (16S rRNA) gene was excluded as a target due to the presence of multiple gene copies, with different sequences in a single genome. Based on the above criteria, the mdh (malate d...
Variations in equid SLC11A1 (NRAMP1) genes and associations with Rhodococcus equi pneumonia in horses. Rhodococcus equi is an important intracellular pathogen of horses, most commonly causing chronic, suppurative bronchopneumonia in foals. Although most foals likely are exposed to environmental R. equi within the 1st few days of life, only some develop R. equi pneumonia, and the basis of differences in susceptibility among foals currently is unknown. In this study, we investigated solute carrier family 11 member 1 (SLC11A1) gene sequences in the 5' untranslated region, exon 1, and a portion of intron 1 for variations in 3 equid species (horse, donkey, zebra) and compared variants within 3 indep...
Effects of platelet-derived growth factor-BB on the metabolic function and morphologic features of equine tendon in explant culture. To evaluate the effects of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) on the metabolic function and morphologic features of equine superficial digital flexor tendon (SDFT) in explant culture. Animals-6 euthanized horses (2 to 5 years old). Methods: Forelimb SDFT explants were cultured for 6 days as untreated control specimens or treated with rhPDGF-BB (1, 10, 50, or 100 ng/mL of medium). Treatment effects on explant gene expression were evaluated via real-time PCR analysis of collagen type I, collagen type III, PDGF-A, and PDGF-B mRNA. Explants were assayed for total colla...
Mammalian male mutation bias: impacts of generation time and regional variation in substitution rates. In mammals, males undergo a greater number of germline cell divisions compared with females. Thus, the male germline accumulates more DNA replication errors, which result in male mutation bias-a higher mutation rate for males than for females. The phenomenon of male mutation bias has been investigated mostly for rodents and primates, however, it has not been studied in detail for other mammalian orders. Here we sequenced and analyzed five introns of three genes (DBX/DBY, UTX/UTY, and ZFX/ZFY) homologous between X and Y chromosomes in several species of perissodactyls (horses and rhinos) and of...
Genome of horsepox virus. Here we present the genomic sequence of horsepox virus (HSPV) isolate MNR-76, an orthopoxvirus (OPV) isolated in 1976 from diseased Mongolian horses. The 212-kbp genome contained 7.5-kbp inverted terminal repeats and lacked extensive terminal tandem repetition. HSPV contained 236 open reading frames (ORFs) with similarity to those in other OPVs, with those in the central 100-kbp region most conserved relative to other OPVs. Phylogenetic analysis of the conserved region indicated that HSPV is closely related to sequenced isolates of vaccinia virus (VACV) and rabbitpox virus, clearly grouping to...
[Prokaryotic expression of the major antigenic domain of equine arteritis virus GL protein and the establishment of putative indirect ELISA assay]. According to the antigenic analysis of equine arteritis virus (EAV) GL protein, one pair of primers were designed, with which the gene fragment coding the high antigenic domain of EAV GL protein was amplified from the EAV genome. The cloned gene was digested with BamH I and Xho I and then inserted into pET-32a and resulted pET-GL1. The pET-GL1 was transformed into the host cell BL21(DE3) and the expression was optimized including cultivation temperature and concentration of IPTG. The aim protein was highly expressed and the obtained recombinant protein manifested well reactiongenicity as was c...
High-resolution gene maps of horse chromosomes 14 and 21: additional insights into evolution and rearrangements of HSA5 homologs in mammals. High-resolution physically ordered gene maps for equine homologs of human chromosome 5 (HSA5), viz., horse chromosomes 14 and 21 (ECA14 and ECA21), were generated by adding 179 new loci (131 gene-specific and 48 microsatellites) to the existing maps of the two chromosomes. The loci were mapped primarily by genotyping on a 5000-rad horse x hamster radiation hybrid panel, of which 28 were mapped by fluorescence in situ hybridization. The approximately fivefold increase in the number of mapped markers on the two chromosomes improves the average resolution of the map to 1 marker/0.9 Mb. The improv...