Genetic variants in horses refer to differences in the DNA sequence among individuals within the species. These variants can affect various traits, including coat color, performance, and susceptibility to diseases. Research on equine genetic variants involves identifying and understanding these differences and their implications for horse breeding, health, and management. Studies often focus on single nucleotide polymorphisms (SNPs), copy number variations (CNVs), and other genetic markers that can influence phenotypic traits. This page aggregates peer-reviewed research studies and scholarly articles that explore the identification, characterization, and impact of genetic variants on equine biology and health.
BMC research notesDecember 16, 2009
Volume 2 255 doi: 10.1186/1756-0500-2-255
Rendo F, Iriondo M, Manzano C, Estonba A.The Cantabrian Coast horse breeds of the Iberian Peninsula have mainly black or bay colored coats, but alleles responsible for a chestnut coat color run in these breeds and occasionally, chestnut horses are born. Chestnut coat color is caused by two recessive alleles, e and e(a), of the melanocortin-1 receptor gene, whereas the presence of the dominant, wild-type E allele produces black or bay coat horses. Because black or bay colored coats are considered as the purebred phenotype for most of the breeds from this region, it is important to have a fast and reliable method to detect alleles caus...
Horin P, Sabakova K, Futas J, Vychodilova L, Necesankova M.In previous work, we found significant associations of horse polymorphic microsatellite and immunity-related (IR) gene markers with Rhodococcus equi infection of foals. Here, a statistically significant association between a single nucleotide polymorphism (SNP) within the interleukin 7 receptor-encoding gene (IL7R) with high R. equi burden in transtracheal aspirates was found (Fisher's F = 0.043, odds ratio: 8.00, 95% confidence interval: 1.127-56.795). Further positional and/or functional candidate genes investigated TLR2, IL13, IL17A, IL28R, TACE/ADAM 17 and GBP1, were not associated with in...
The Journal of heredityNovember 25, 2009
Volume 101, Issue 2 246-250 doi: 10.1093/jhered/esp091
Mittmann EH, Lampe V, Mömke S, Zeitz A, Distl O.The availability of a high-quality draft sequence of the horse makes known the physical location of microsatellites. The aim of the present study was to establish a highly polymorphic minimal screening set of microsatellite markers for horses (MSSH) annotated on the horse genome assembly EquCab2.0. We have used the previously reported linkage and radiation hybrid maps and have extended these marker sets by filling in gaps as noted from annotation on the horse sequence. This MSSH covers all autosomes and the X chromosome with 322 evenly spaced microsatellites whose positions were determined on ...
Lampe V, Dierks C, Distl O.Osteochondrosis (OC) is an inherited developmental disease in young horses most frequently observed in thoroughbreds, trotters, warmblood and coldblood horses. Quantitative trait loci (QTL) for equine OC have been identified in Hanoverian warmblood horses employing a whole genome scan with microsatellites. A QTL on ECA16 reached the genome-wide significance level for hock osteochondrosis dissecans (OCD). The aim of this study was to refine this QTL on ECA16 using an extended marker set of 34 newly developed microsatellites and 15 single nucleotide polymorphisms (SNPs). We used the same 14 pate...
McCue ME, Armién AG, Lucio M, Mickelson JR, Valberg SJ.Polysaccharide storage myopathy (PSSM) has been found in more than 35 different horse breeds through identification of abnormal storage of polysaccharide in muscle biopsies. A dominant mutation in the glycogen synthase 1 gene (GYS1) accounts for a substantial proportion of PSSM cases in at least 17 breeds, including Quarter Horses, but some horses diagnosed with PSSM by muscle histopathologic analysis are negative for the mutation. We hypothesized that a second distinct form of glycogen storage disease exists in GYS1-negative horses with PSSM. The objectives of this study were to compare the h...
Haase B, Obexer-Ruff G, Dolf G, Rieder S, Burger D, Poncet PA, Gerber V, Howard J, Leeb T.The KIT receptor protein-tyrosine kinase plays an important role during embryonic development. Activation of KIT is crucial for the development of various cell lineages such as melanoblasts, stem cells of the haematopoietic system, spermatogonia and intestinal cells of Cajal. In mice, many mutations in the Kit gene cause pigmentation disorders accompanied by pleiotropic effects on blood cells and male fertility. Previous work has demonstrated that dominant white Franches-Montagnes horses carry one copy of the KIT gene with the p.Y717X mutation. The targeted breeding of white horses would be et...
Nieto JE, Aleman M.Anesthetic-induced malignant hyperthermia has been documented in Quarter Horses and is caused by a single-point mutation in the ryanodine receptor 1 gene at nucleotide C7360G generating a R2454G amino acid substitution. An accurate, faster molecular test that is less prone to contamination would facilitate screening for the mutation in horses intended for breeding, in those undergoing surgical procedures, and in those with clinical signs compatible with malignant hyperthermia. Objective: To report a rapid and accurate method for the detection of the ryanodine receptor 1 C7360G mutation. Method...
Aleman M, Nieto JE, Magdesian KG.Anesthetic-induced malignant hyperthermia (MH) has been documented in Quarter Horses with a single point mutation in the ryanodine receptor 1 gene (RyR1) at nucleotide C7360G, generating a R2454G amino acid substitution. However, there have been no reports of nonanesthetic manifestations of MH in horses with the C7360G mutation. Objective: To describe clinical manifestations of Quarter Horses with the C7360G mutation. Methods: Eleven Quarter Horses with the RyR1 C7360G mutation. Methods: This prospective study included horses with suspected MH, undetermined etiology of sudden death, death with...
McCue ME, Valberg SJ, Jackson M, Borgia L, Lucio M, Mickelson JR.In this study we examined a family of Quarter Horses with Polysaccharide Storage Myopathy (PSSM) with a dominant mutation in the skeletal muscle glycogen synthase (GYS1) gene. A subset of horses within this family had a more severe and occasionally fatal PSSM phenotype. The purpose of this study was to identify a modifying gene(s) for the severe clinical phenotype. A genetic association analysis was used to identify RYR1 as a candidate modifying gene. A rare, known equine RYR1 mutation, associated with malignant hyperthermia (MH), was found to segregate in this GYS1 PSSM family. Retrospective ...
Choi SK, Cho CY, Yeon SH, Cho BW, Cho GJ.Genetic characterization of the Jeju horse (JH) was performed to construct a correct pedigree of the JH family. A total of 111 horses including 79 JH were genotyped using 20 microsatellite loci. The number of alleles varied from 5 to 11 (mean 7.45) in the JH. The observed heterozygosity and expected heterozygosity ranged from 0.293 to 0.891 and from 0.357 to 0.841, respectively. The polymorphic information contents (PIC) ranged from 0.335 to 0.816. AHT4, ASB2, ASB17, ASB23, CA425, HMS2, HMS3, HTG10, LEX3 and VHL20 loci had relatively high PIC values (> 0.7). The total exclusion probability ...
McCue ME, Valberg SJ, Lucio M, Mickelson JR.A missense mutation in the GYS1 gene was recently described in horses with polysaccharide storage myopathy (PSSM). Objective: The first objective was to determine the prevalence of the GYS1 mutation in horses with PSSM from diverse breeds. The second objective was to determine if the prevalence of the GYS1 mutation differed between horses diagnosed with PSSM based on grade 1 (typically amylase-sensitive) or grade 2 (typically amylase-resistant) polysaccharide. Methods: Eight hundred and thirty-one PSSM horses from 36 breeds. Methods: Horses with PSSM diagnosed by histopathology of skeletal mus...
Lewis MJ, Meehan M, Owen P, Woof JM.The M protein of Streptococcus equi subsp. equi known as fibrinogen-binding protein (FgBP) is a cell wall-associated protein with antiphagocytic activity that binds IgG. Recombinant versions of the seven equine IgG subclasses were used to investigate the subclass specificity of FgBP. FgBP bound predominantly to equine IgG4 and IgG7, with little or no binding to the other subclasses. Competitive binding experiments revealed that FgBP could inhibit the binding of staphylococcal protein A and streptococcal protein G to both IgG4 and IgG7, implicating the Fc interdomain region in binding to FgBP. ...
McCue ME, Valberg SJ, Miller MB, Wade C, DiMauro S, Akman HO, Mickelson JR.Polysaccharide storage myopathy (PSSM) is a novel glycogenosis in horses characterized by abnormal glycogen accumulation in skeletal muscle and muscle damage with exertion. It is unlike glycogen storage diseases resulting from known defects in glycogenolysis, glycolysis, and glycogen synthesis that have been described in humans and domestic animals. A genome-wide association identified GYS1, encoding skeletal muscle glycogen synthase (GS), as a candidate gene for PSSM. DNA sequence analysis revealed a mutation resulting in an arginine-to-histidine substitution in a highly conserved region of G...
Sparks WO, Dorman KS, Liu S, Carpenter S.Equine infectious anemia virus (EIAV) exhibits a high rate of genetic variation in vivo, and results in a clinically variable disease in infected horses. In vivo populations of EIAV have been characterized by the presence of distinct, genetic subpopulations of Rev that differ in phenotype and fluctuate in dominance in a manner coincident with each clinical stage of disease. This study examined the specific mutations that arose in vivo and altered the phenotype. The Rev protein was found to be highly conserved, and only 10 aa mutations were observed at a frequency greater than 10 % in the sampl...
Dugarjaviin M, Yang H.Mongolian horse is a kind of important breed resource of local horses in our country. It has a lot of advantages such as powerful endurance, rough feeding resistance, and strong disease resistance. These advantages have become driving force for in-depth study on Mongolian horse. Genetic diversity can reflect all the genetic information of a species or a variety, namely, it reflects the richness of genetic diversity and confirms the degree of uniqueness of genetic resources through genetic markers. This paper introduces the progress in the study on genetic diversity of Mongolian horse in many a...
The Journal of heredityJanuary 27, 2008
Volume 99, Issue 2 125-129 doi: 10.1093/jhered/esm106
Wittwer C, Dierks C, Hamann H, Distl O.A previously accomplished whole-genome scan for osteochondrosis (OC) and OC dissecans (OCD) in South German Coldblood horses using 250 microsatellite markers identified putative quantitative trait loci (QTL). A chromosome-wide significant QTL for fetlock OCD was found on Equus caballus chromosome (ECA) 4q at a relative position of 70.0-73.3 cM. The aim of this study was to analyze associations of single nucleotide polymorphisms (SNPs) in candidate genes for OC in this region. The association analysis included 32 affected and 64 unaffected horses. Three SNPs located in intron 8, intron 9, and 3...
Wittwer C, Löhring K, Drögemüller C, Hamann H, Rosenberger E, Distl O.The aim of this study was to identify quantitative trait loci (QTL) for osteochondrosis (OC) and palmar/plantar osseous fragments (POF) in fetlock joints in a whole-genome scan of 219 South German Coldblood horses. Symptoms of OC and POF were checked by radiography in 117 South German Coldblood horses at a mean age of 17 months. The radiographic examination comprised the fetlock and hock joints of all limbs. The genome scan included 157 polymorphic microsatellite markers. All microsatellite markers were equally spaced over the 31 autosomes and the X chromosome, with an average distance of 17.7...
Aguilar PV, Weaver SC, Basler CF.Eastern equine encephalitis virus (EEEV) causes sporadic but often severe cases of human and equine neurological disease in North America. To determine how EEEV may evade innate immune responses, we screened individual EEEV proteins for the ability to rescue the growth of a Newcastle disease virus expressing green fluorescent protein (NDV-GFP) from the antiviral effects of interferon (IFN). Only expression of the EEEV capsid facilitated NDV-GFP replication. Inhibition of the antiviral effects of IFN by the capsid appears to occur through a general inhibition of cellular gene expression. For ex...
Luís C, Juras R, Oom MM, Cothran EG.There are three native Portuguese horse breeds: Lusitano, Sorraia and Garrano. This study compares diversity patterns of 17 protein and 12 microsatellite markers in these three as well as 30 other breeds to infer relationships among the breeds and to compare levels of polymorphism of these breeds for use in conservation efforts. The Garrano and the Lusitano showed a high level of genetic diversity, similar to that observed for most of the other analysed breeds, while the Sorraia and Friesian breeds showed low levels of variation for both genetic marker types. The combined protein and microsate...
Pei Y, Parreira V, Nicholson VM, Prescott JF.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 ...
de Val N, Herschbach H, Potier N, Dorsselaer AV, Crichton RR.An essential difference between eukaryotic ferritins and bacterioferritins is that the latter contain naturally, in vivo haem as Fe-protoporphyrin IX. This haem is located in a hydrophobic pocket along the 2-fold symmetry axes and is liganded by two Met 52. However, in in vivo studies, a cofactor has been isolated in horse spleen apoferritin similar to protoporphyrin IX; in in vitro experiments, it has been shown that horse spleen apoferritin is able to interact with haem. Studies of haemin (Fe(III)-PPIX) incorporation into horse spleen apoferritin have been carried out, which show that the me...
Sánchez MD, Pierson TC, Degrace MM, Mattei LM, Hanna SL, Del Piero F, Doms RW.A major neutralizing epitope (here referred to as the T332 epitope) located on the lateral surface of domain III (DIII) of the West Nile virus (WNV) envelope protein has been identified based on the analysis of murine monoclonal antibodies. However, little is known about the humoral immune response against WNV in a natural host or whether DIII in general or the T332 epitope in particular are important targets of neutralizing antibodies in vivo. To characterize the types of antibodies produced during infection with WNV, we studied a group of naturally infected horses. Using immune adsorption as...
Hamilton A, Robinson C, Sutcliffe IC, Slater J, Maskell DJ, Davis-Poynter N, Smith K, Waller A, Harrington DJ.Streptococcus equi is the causative agent of strangles, a prevalent and highly contagious disease of horses. Despite the animal suffering and economic burden associated with strangles, little is known about the molecular basis of S. equi virulence. Here we have investigated the contributions of a specific lipoprotein and the general lipoprotein processing pathway to the abilities of S. equi to colonize equine epithelial tissues in vitro and to cause disease in both a mouse model and the natural host in vivo. Colonization of air interface organ cultures after they were inoculated with a mutant ...
Goetting-Minesky MP, Makova KD.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...
Young AE, Bower LP, Affolter VK, De Cock HE, Ferraro GL, Bannasch DL.Chronic progressive lymphedema (CPL) is a debilitating condition identified in Clydesdales, Shires and Belgian draft horses and results in progressive swelling of the lower legs associated with the development of thick skin folds, ulcerations, fibrosis and marked hyperkeratosis. The result is severe discomfort and recurrent secondary infection, often requiring euthanasia. Due to the delayed onset, many horses are bred prior to diagnosis. CPL has only been documented in three related draft horse breeds, suggesting a genetic cause. Determining the molecular basis would enable owners to test hors...
Momozawa Y, Takeuchi Y, Tozaki T, Kikusui T, Hasegawa T, Raudsepp T, Chowdhary BP, Kusunose R, Mori Y.Equine anxiety trait is considered an important temperament in various situations, including riding, training, and daily care. This study examined the polymorphism of the equine serotonin transporter (SLC6A4) gene as a candidate genetic element influencing equine anxiety trait. The sequence of the coding region of this gene was highly homologous with those of other mammals, and four single nucleotide polymorphisms were found by comparing the sequences of ten genetically unrelated thoroughbred horses. Radiation hybrid mapping revealed that this gene was located 26.92 cR from neurofibromin 1 on ...
Pielberg G, Mikko S, Sandberg K, Andersson L.Grey horses are born coloured, turn progressively grey and often develop melanomas late in life. Grey shows an autosomal dominant inheritance and the locus has previously been mapped to horse chromosome 25 (ECA25), around the TXN gene. We have now developed eight new single nucleotide polymorphisms (SNPs) associated with genes on ECA25 using information on the linear order of genes on human chromosome 9q, as well as the human and mouse coding sequences. These SNPs were mapped in relation to the Grey locus using more than 300 progeny from matings between two Swedish Warmblood grey stallions and...
Keyser-Tracqui C, Blandin-Frappin P, Francfort HP, Ricaut FX, Lepetz S, Crubézy E, Samashev Z, Ludes B.Sequence polymorphism of the mitochondrial DNA D-loop was used to determine the genetic diversity of horses recovered from a Scythian princely tomb dating from the beginning of the 3rd century BC. Eight haplotypes were found among the 13 ancient horse samples tested. Phylogenetical analysis showed that these ancient horse's sequences, along with two Yakut ones, were distributed throughout the tree defined by modern horses' sequences and are closely related to them. No clear geographical affiliation of the specimens studied was thus determined. Our work, among others, supports the very ancient ...
Harvey SP, Minter JM.In this study, the subspecies differentiation of 25 isolates of Burkholderia mallei was attempted based on their ribotype polymorphisms. The isolates were from human and equine infections that occurred at various times around the world. DNA samples from each isolate were digested separately with PstI and EcoRI enzymes and probed with an Escherichia coli-derived 18-mer rDNA sequence to identify diagnostic fragments. Seventeen distinct ribotypes were identified from the combined data obtained with the two restriction enzymes. The results demonstrate the general utility of ribotyping for the subs...
Zimmermann E, Distl O.Before the genomics era, heritability estimates were performed using pedigree data. Data collection for pedigree analysis is time consuming and holds the risk of incorrect or incomplete data. With the availability of SNP-based arrays, heritability can now be estimated based on genotyping data. We used SNP array and 1.6 million imputed genotype data with different minor allele frequency restrictions to estimate heritabilities for osteochondrosis dissecans in the fetlock, hock and stifle joints of 446 Hanoverian warmblood horses. SNP-based heritabilities were estimated using a genomic restricted...
Nolte W, Alkhoder H, Wobbe M, Stock KF, Kalm E, Vosgerau S, Krattenmacher N, Thaller G, Tetens J, Kühn C.In horses, parentage control is currently performed based on an internationally standardized panel of 17 microsatellite (MS) markers comprising 12 mandatory and five optional markers. Unlike MS, single nucleotide polymorphism (SNP) profiles support a wider portfolio of genomic applications, including parentage control. A transition to SNP-based parentage control is favorable, but requires additional efforts for ensuring generation-overlapping availability of marker genotypes of the same type. To avoid double genotyping of either parents or offspring for changing to SNP technology and enable ef...
Bolzon C, Joonè CJ, Schulman ML, Harper CK, Villagómez DA, King WA, Révay T.Disorders of sex development (DSD) have long been documented in domestic animal species including horses. However, there is only a single report of an androgen receptor (AR) mutation causative of such a DSD syndrome in a horse pedigree. Here, we present a new familial AR mutation in horses. A missense mutation (c.2042G>C) at AR exon 4 explains the segregation of the DSD in a Thoroughbred horse pedigree. The mutation, expected to affect the ligand-binding domain of the AR protein, led to complete androgen insensitivity of 64,XY SRY+, testicular DSD individuals. Additionally, the design of a ...
Wittwer C, Löhring K, Drögemüller C, Hamann H, Rosenberger E, Distl O.The aim of this study was to identify quantitative trait loci (QTL) for osteochondrosis (OC) and palmar/plantar osseous fragments (POF) in fetlock joints in a whole-genome scan of 219 South German Coldblood horses. Symptoms of OC and POF were checked by radiography in 117 South German Coldblood horses at a mean age of 17 months. The radiographic examination comprised the fetlock and hock joints of all limbs. The genome scan included 157 polymorphic microsatellite markers. All microsatellite markers were equally spaced over the 31 autosomes and the X chromosome, with an average distance of 17.7...
Campana MG, Whitten CM, Edwards CJ, Stock F, Murphy AM, Binns MM, Barker GW, Bower MA.Historic DNA data have the potential to identify phenotypic information otherwise invisible in the historical, archaeological and palaeontological record. In order to determine whether a single nucleotide polymorphism typing protocol based on single based extension (SNaPshot™) could produce reliable phenotypic data from historic samples, we genotyped three coat colour markers for a sample of historic Thoroughbred horses for which both phenotypic and correct genotypic information were known from pedigree information in the General Stud Book. Experimental results were consistent with the pedig...
Luttman AM, Komine M, Thaiwong T, Carpenter T, Ewart SL, Kiupel M, Langohr IM, Venta PJ.Tetranucleotide and pentanucleotide short tandem repeat (hereafter termed tetraSTR and pentaSTR) polymorphisms have properties that make them desirable for DNA profiling and paternity testing. However, certain species, such as the horse, have far fewer tetraSTRs than other species and for this reason dinucleotide STRs (diSTRs) have become the standard for DNA profiling in horses, despite being less desirable for technical reasons. During our testing of a series of candidate genes as potentially underlying a heritable condition characterized by megaesophagus in the Friesian horse breed, we foun...
Li Y, Yao J, Chang M, Nikolic D, Yu L, Yager JD, Mesecar AD, van Breemen RB, Bolton JL.Catechol-O-methyltransferase (COMT) plays an important role in the inactivation of biologically active and toxic catechols. It has been shown that COMT is genetically polymorphic with a wild-type and variant form where a valine has been substituted with a methionine. Several, but not all, epidemiological studies have shown that women, homozygous with the variant form, have an increased risk of developing breast cancer. Previously, we showed that 4-hydroxyequilenin (4-OHEN), a cytotoxic/genotoxic equine catechol estrogen metabolite, is both a substrate of COMT and an irreversible inhibitor of t...
Madden CR, Shih DS.Sequential passage of the tissue culture-adapted prototype strain of EIAV in fetal donkey dermal (FDD) cell cultures generated a virus stock which exhibits cytopathic effects in FDD cell cultures. In this study, the effects of the long terminal repeat (LTR) region on virus replication and cytopathogenicity were examined. The FDD-adapted virus LTR was found to contain a number of base pair mutations and a large insertion within the U3 region in comparison with the previously characterized LTR, lambda12. Transient gene expression studies showed that basal promoter activity, in FDD cell cultures,...
Lee J, Kang YJ, Kim YK, Choi JY, Shin SM, Shin MC.The influences of diet and environmental factors on gut microbial profiles have been widely acknowledged; however, the specific roles of host genetics remain uncertain. To unravel host genetic effects, we raised 47 Jeju crossbred (Jeju × Thoroughbred) foals that exhibited higher genetic diversity. Foals were raised under identical environmental conditions and diets. Microbial composition revealed that Firmicutes, Bacteroidetes, and Spirochaetes were the predominant phyla. We identified 31 host-microbiome associations by utilizing 47,668 single nucleotide polymorphisms (SNPs) and 734 taxa with...
Nieto JE, Aleman M.Anesthetic-induced malignant hyperthermia has been documented in Quarter Horses and is caused by a single-point mutation in the ryanodine receptor 1 gene at nucleotide C7360G generating a R2454G amino acid substitution. An accurate, faster molecular test that is less prone to contamination would facilitate screening for the mutation in horses intended for breeding, in those undergoing surgical procedures, and in those with clinical signs compatible with malignant hyperthermia. Objective: To report a rapid and accurate method for the detection of the ryanodine receptor 1 C7360G mutation. Method...
Wypchło M, Korwin-Kossakowska A, Bereznowski A, Hecold M, Lewczuk D.The aim of this research was to evaluate the polymorphisms of selected genes and to find their potential effect on the occurrence of osteochondrosis in Polish Warmbloods (sport horse breeds). The study was conducted on a group of 198 horses subjected to official performance tests. Investigated joints-fetlock, hock and stifle-were X-rayed twice, once before and again at the end of the tests (first and second examination), and on this basis the degree of disease was evaluated. Based on the results of previous research, 13 candidate genes potentially associated with the occurrence of osteochondro...
Giantsis IA, Diakakis NE, Avdi M.Tendinopathies constitute a very common category of musculoskeletal disorders, causing economic losses in the equine industry and animal welfare issues in horse populations. Sport and racehorses are in general sensitive to tendinopathies, whereas local indigenous horse populations are often more tolerant to various disorders. Particularly, indigenous Greek horse breeds have evolved and adapted in the rough topographic features of mountainous and semimountainous Greek terrain and are less prone to develop tendinopathies. Susceptibility to tendinopathy has been proposed to be associated with thr...
Haase B, Obexer-Ruff G, Dolf G, Rieder S, Burger D, Poncet PA, Gerber V, Howard J, Leeb T.The KIT receptor protein-tyrosine kinase plays an important role during embryonic development. Activation of KIT is crucial for the development of various cell lineages such as melanoblasts, stem cells of the haematopoietic system, spermatogonia and intestinal cells of Cajal. In mice, many mutations in the Kit gene cause pigmentation disorders accompanied by pleiotropic effects on blood cells and male fertility. Previous work has demonstrated that dominant white Franches-Montagnes horses carry one copy of the KIT gene with the p.Y717X mutation. The targeted breeding of white horses would be et...
Horsington JJ, Gilkerson JR, Hartley CA.Equine rhinitis B virus (ERBV) is the single species in the genus Erbovirus, family Picornaviridae. Equine rhinitis B viruses exist in three serotypes and are associated with respiratory disease in horses. Members of the species vary in stability at acid pH. To date there has been discordance in genotype, serotype and acid stability phenotype groupings. To identify capsid regions associated with acid stability, two viruses were serially treated at pH 3.3 to isolate acid-stable mutants. An acid-stable mutant of the prototype acid-labile serotype 1 virus contained a single amino acid change in t...
Field HJ, Awan AR, de la Fuente R.The compound (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA) had been previously shown to be highly effective in treatment of EHV-1 in a murine model for the equine disease. This paper describes the isolation of a series of mutants resistant to the drug. Resistance was demonstrated in cell culture and one mutant was tested in a murine model. The resistant mutant was pathogenic for mice; infectious virus was recovered from respiratory tissues and blood at levels similar to the parental virus. However, the mutant showed a significant degree of resistance in vivo, thus proving the viru...
Retamal P, Ríos M, Cheuquepán F, Abalos P, Pizarro-Lucero J, Borie C, Gutierrez J.Corynebacterium pseudotuberculosis is a widespread facultative intracellular pathogen that causes caseous lymphadenitis disease in sheep and goats, and generates cutaneous abscesses and granulomas in horses and cattle. Although some genes have been studied for diagnostic and phylogenetic analysis within the genus Corynebacterium, at subspecies level the pathogen has been poorly analyzed. The aim of this study was to characterize C. pseudotuberculosis strains isolated from domestic animals, through the sequencing of a hypervariable rpoB gene segment. As result, there were identified host associ...
Hack YL, Crabtree EE, Avila F, Sutton RB, Grahn R, Oh A, Gilger B, Bellone RR.The only known genetic cause of congenital stationary night blindness (CSNB) in horses is a 1378 bp insertion in TRPM1. However, an affected Tennessee Walking Horse was found to have no copies of this variant. Objective: To identify the genetic cause for CSNB in an affected Tennessee Walking Horse. Methods: Case report detailing a whole-genome sequencing (WGS) approach to identify a causal variant. Methods: A complete ophthalmic exam, including an electroretinogram (ERG), was performed on suspected CSNB-affected horse. WGS data were generated from the case and compared with data from seven ot...
Meta geneJune 30, 2015
Volume 5 120-123 doi: 10.1016/j.mgene.2015.06.006
Ito H, Langenhorst T, Ogden R, Inoue-Murayama M.Androgen receptor genes (AR) have been found to have associations with reproductive development, behavioral traits, and disorders in humans. However, the influence of similar genetic effects on the behavior of other animals is scarce. We examined the loci AR glutamine repeat (ARQ) in 44 Grevy's zebras, 23 plains zebras, and three mountain zebras, and compared them with those of domesticated horses. We observed polymorphism among zebra species and between zebra and horse. As androgens such as testosterone influence aggressiveness, AR polymorphism among equid species may be associated with diffe...
Brard S, Ricard A.An A/C mutation responsible for the ability to pace in horses was recently discovered in the gene. It has also been proven that allele C has a negative effect on trotters' performances. However, in French trotters (FT), the frequency of allele A is only 77% due to an unexpected positive effect of allele C in late-career FT performances. Here we set out to ascertain whether the genotype at SNP (linked to ) should be used to compute EBV for FT. We used the genotypes of 630 horses, with 41,711 SNP retained. The pedigree comprised 5,699 horses. Qualification status (trotters need to complete a 2,0...
Byambaragchaa M, Choi SH, Joo HE, Kim SG, Kim YJ, Park GE, Kang MH, Min KS.Equine chorionic gonadotropin (eCG), produced by the endometrial cups of the placenta after the first trimester, is a specific glycoprotein that displays dual luteinizing hormone (LH)-like and follicle-stimulating hormone (FSH)-like effects in non-equid species. However, in equidaes, eCG exhibits only LH-like activity. To identify the specific biological functions of glycosylated sites in eCG, we constructed the following site mutants of N- and O-linked glycosylation: eCGβ/αΔ56, substitution of α-subunit N-linked glycosylation site; eCGβ-D/α, deletion of the O-linked glycosylation sites ...
Kriegshäuser G, Wutz G, Lea S, Stuart D, Skern T, Kuechler E.Mouse monoclonal antibodies (mAbs) were employed to select neutralization escape mutants of equine rhinitis A virus (ERAV). Amino acid changes in the ERAV mutants resulting in resistance to neutralization were identified in capsid protein VP1 at Lys-114, Pro-240 and Thr-241. Although the changes were located in different parts of the polypeptide chain, these mutants exhibited cross-resistance against all four mAbs employed, indicating that these residues contribute to a single immunogenic site. To explain this result, we constructed a model of the three-dimensional structure of the ERAV capsid...
Padilha FGF, El-Jaick KB, de Castro L, Moreira ADS, Ferreira AMR.Polymorphisms in MSTN have previously been associated with equine performance. Therefore, the aim of this study was to identify variants in intron 1 in 16 Brazilian Sport Horses selected for competition in eventing and their possible effects of selection on performance. Among the nine variants identified, eight had already been reported in previous studies or genomic databases, although they showed differences in frequencies when compared with other horse breeds. Moreover, a new mutation was identified in two horses, both in heterozygous form. Considering the absence of molecular studies in t...
Ayala-Valdovinos MA, Galindo-García J, Sánchez-Chiprés D, Duifhuis-Rivera T, Anguiano-Estrella R.The 'Gait keeper' mutation in the DMRT3 gene alters locomotion and gait patterns in horses. This mutation (C>A) has been found in all gaited breeds of horses analyzed but is absent in most non-gaited breeds. We developed a new mutagenically separated polymerase chain reaction (MS-PCR) based method for simple detection of horse DMRT3 genotype. Our method was applied in a preliminary study to determine DMRT3 allele frequencies in 78 Azteca horses (AZ) and 53 Costa Rican Saddle Horses (CRSH). We found a wild-type C allele frequency of 100% in the AZ horses. For the CRSH, the wild-type C freque...
Neubauer A, Meindl A, Osterrieder N.The equine herpesvirus 1 (EHV-1) modified live vaccine strain RacH is apathogenic for both laboratory animals and the natural host. The apathogenicity of RacH was caused by serial passages of the virus in heterologous cells. When compared to the virulent parental strain RacL11 several changes in the RacH genome occurred. Previous results have shown that the loss of the IR6 gene correlated with the loss of virulence. Additional important mutations were observed within the US2 gene which is directly adjacent to the IR6 gene and within the glycoprotein B (gB) gene. To answer the question whether ...
Boudreaux MK, Koehler J, Habecker PL, Del Piero F.Exercise-induced pulmonary hemorrhage (EIPH) is a common disorder of equine athletes. The role of polymorphisms in genes encoding hemostasis-regulatory proteins in horses with abnormal hemorrhage is unknown. Objective: The goal of this study was to evaluate the genes encoding 2 ectonucleotidases, CD39/NTPDase-1 and CD39L1/NTPDase-2, and one ecto-5' nucleotidase, CD73, in horses with abnormal hemorrhage or pathologic changes consistent with EIPH. Methods: Twenty-three horses with histories of abnormal hemorrhage, 8 horses with gastrointestinal signs, and 45 healthy horses were evaluated using p...
Zhang H, Zhou T, Su L, Wang H, Zhang B, Su Y.Strangles, which is caused by Streptococcus equi subspecies equi (S. equi), is one of the most prevalent equine infectious diseases with worldwide distribution and leads to serious economic loss in the horse industry. Sortase A (srtA) is a transpeptidase that anchors multiple virulence-associated surface proteins to the cell surface of S. equi. srtA plays a major role in S. equi infection and colonization of the host cell. In this study, we aimed to investigate the effects of srtA mutation on the phagocytic activity and immunogenicity of S. equi. The point-mutated recombinant sortases, includi...
Tandon R, Lyons ET, Tolliver SC, Kaplan RM.Cyathostomins are among the most important intestinal nematodes of horses, yet, the literature on the molecular genetics of these worms is scarce. In this study, the technique of amplified fragment length polymorphism (AFLP) was applied to study the genetic diversity as well as to determine the effect of moxidectin selection on the population genetic diversity for Cylicocyclus nassatus, one of the most common cyathostomin species. Genomic DNAs from 30 individual male worms were used from each of two populations: an avermectin-milbemycin (AM)-naive population (Population-S) and a population der...
