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.
Boakari YL, El-Sheikh Ali H, Dini P, Loux S, Fernandes CB, Scoggin K, Esteller-Vico A, Lawrence L, Ball B.High blood urea nitrogen (BUN) in cows and ewes has a negative effect on embryo development; however, no comparable studies have been published in mares. The aims of the present study were to evaluate the effects of high BUN on blastocoele fluid, systemic progesterone and Day 14 equine embryos. When a follicle with a mean (±s.e.m.) diameter of 25±3mm was detected, mares were administered urea (0.4g kg-1) with sweet feed and molasses (n=9) or sweet feed and molasses alone (control; n=10). Blood samples were collected every other day. Mares were subjected to AI and the day ovulation was detect...
Migdał A, Migdał Ł, Oczkowicz M, Okólski A, Chełmońska-Soyta A.The aim of this study was to investigate the molecular mechanisms leading to the identification of pathogens by congenital immune receptors in foals up to 60 days of age. The study was conducted on 16 foal Polish Pony Horses (Polish Konik) divided into two study groups: control ( = 9) and experimental ( = 7). Foals from the experimental group received an intramuscular duplicate injection of 5 mL of Biotropina (Biowet) at 35 and 40 days of age. The RNA isolated from venous blood was used to evaluate the expression of the, , and genes using RT-PCR. The results of the experiment demonstrated a s...
Sánchez-Calabuig MJ, Fernández-González R, Hamdi M, Smits K, López-Cardona AP, Serres C, Macías-García B, Gutiérrez-Adán A.Equine embryos exhibit an unusual pattern of glucose tolerance in vitro and are currently cultured in hyperglycaemic conditions. Objective: Our main objective was to analyse the effect of different glucose concentrations on in vitro-produced equine embryo development and quality. Methods: Experiments comparing in vitro and in vivo produced embryos. Methods: Oocytes (n = 641) were collected from post-mortem ovaries, matured in vitro and fertilised by intracytoplasmic sperm injection (ICSI). Embryo culture was divided from Day 0 to Day 4 and from Day 4 to Day 9 in three groups: 5-10 (5 and 10...
Haythorn A, Young M, Stanton J, Zhang J, Mueller POE, Halper J.Equine degenerative suspensory ligament desmitis (DSLD) is a systemic connective tissue disorder first identified in Peruvian Paso horses but afflicting other horse breeds as well. Inappropriate accumulation of proteoglycans in connective tissues, most prominently in tendons and ligaments, leads to progressive and debilitating lameness and pain. It is largely unknown what drives the overproduction of proteoglycans, but our previous studies suggest involvement of bone morphogenetic protein 2 (BMP2), a member of the transforming growth factor-β (TGFβ) family, impacting synthesis of proteoglyca...
Nguyen TB, Paul RC, Okuda Y, LE TNA, Pham PTK, Kaissar KJ, Kazhmurat A, Bibigul S, Bakhtin M, Kazymbet P, Maratbek SZ, Meldebekov A, Nishibori M....The Kushum is a relatively new breed of horses in Kazakhstan that was established in the middle of the 20th century through a cross between mares of Kazakhstan local horses and stallions of Thoroughbred, Trotter, and Russian Don breeds to supply military horses. To reveal the genetic characteristics of this breed, we investigated haplotypes of mitochondrial DNA (mtDNA) and single-nucleotide polymorphisms of the Y chromosome, as well as genotypes of five functional genes associated with coat color, body composition, and locomotion traits. We detected 10 mtDNA haplotypes that fell into 8 of the ...
Dittmer KE, Heathcott RW, Marshall JC, Azarpeykan S.The aim of this preliminary study was to determine the relative expression of phosphatonin pathway-related genes in normal dog, sheep and horse kidneys and to explore the relationships between the different genes. Kidneys were collected post-mortem from 10 sheep, 10 horses and 8 dogs. RNA was extracted, followed by reverse transcriptase quantitative polymerase chain reaction for fibroblast growth factor receptor 1 IIIc (), sodium-phosphate co-transporter () 1 (), (), (), parathyroid hormone 1 receptor (), klotho (), vitamin D receptor (), 1a-hydroxylase () and 24-hydroxylase (). was highly ...
Tonekaboni FR, Narenjisani R, Staji H, Ahmadi-Hamedani M.This investigation aimed to compare the cell-free fetal DNA (cffDNA) plasma present in three trimesters of pregnancy in Torkaman pregnant mare. Peripheral blood samples of 32 pregnant mares in three trimesters of pregnancy were collected in tubes containing ethylenediaminetetraacetic acid at three time points. Circulating cffDNA was extracted from 3 mL of maternal plasma. Using outer and inner primers, a conventional polymerase chain reaction was performed for the sex-determining region Y (SRY) gene present in the Y chromosome. Of the total 32 Torkaman pregnant mares, 24 were carrying male fe...
Schaefer RJ, Cullen J, Manfredi J, McCue M.A gene's response to an environment is tightly bound to the underlying genetic variation present in an individual's genome and varies greatly depending on the tissue it is being expressed in. Gene co-expression networks provide a mechanism to understand and interpret the collective transcriptional responses of genes. Here, we use the Camoco co-expression network framework to characterize the transcriptional landscape of adipose and gluteal muscle tissue in 83 domestic horses (Equus caballus) representing 5 different breeds. In each tissue, gene expression profiles, capturing transcriptional re...
Moro LN, Viale DL, Bastón JI, Arnold V, Suvá M, Wiedenmann E, Olguín M, Miriuka S, Vichera G.The application of new technologies for gene editing in horses may allow the generation of improved sportive individuals. Here, we aimed to knock out the myostatin gene (MSTN), a negative regulator of muscle mass development, using CRISPR/Cas9 and to generate edited embryos for the first time in horses. We nucleofected horse fetal fibroblasts with 1, 2 or 5 µg of 2 different gRNA/Cas9 plasmids targeting the first exon of MSTN. We observed that increasing plasmid concentrations improved mutation efficiency. The average efficiency was 63.6% for gRNA1 (14/22 edited clonal cell lines) and 96.2% ...
Autry JM, Karim CB, Cocco M, Carlson SF, Thomas DD, Valberg SJ.We have analyzed protein expression and enzyme activity of the sarcoplasmic reticulum Ca2+-transporting ATPase (SERCA) in horse gluteal muscle. Horses exhibit a high incidence of recurrent exertional rhabdomyolysis, with myosolic Ca2+ proposed, but yet to be established, as the underlying cause. To better assess Ca2+ regulatory mechanisms, we developed an improved protocol for isolating sarcoplasmic reticulum (SR) vesicles from horse skeletal muscle, based on mechanical homogenization and optimized parameters for differential centrifugation. Immunoblotting identified the peak subcellular fract...
Bizarria Dos Santos W, Pimenta Schettini G, Fonseca MG, Pereira GL, Loyola Chardulo LA, Rodrigues Machado Neto O, Baldassini WA, Nunes de Oliveira H....With the availability of high-density SNP panels and the establishment of approaches for characterizing homozygosity and heterozygosity sites, it is possible to access fine-scale information regarding genomes, providing more than just comparisons of different inbreeding coefficients. This is the first study that seeks to access such information for the Mangalarga Marchador (MM) horse breed on a genomic scale. To this end, we aimed to assess inbreeding levels using different coefficients, as well as to characterize homozygous and heterozygous runs in the population. Using Axiom ® Equine Genoty...
Laroucau K, Aaziz R, Vorimore F, Varghese K, Deshayes T, Bertin C, Delannoy S, Sami AM, Al Batel M, El Shorbagy M, Almutawaa KAW, Alanezi SJ....Glanders is a contagious zoonotic disease caused by Burkholderia mallei. Following the detection of glanders positive horses using the OIE complement fixation test, the tissues of two horses were analysed by PCR. While PCR systems targeting the Burkholderia pseudomallei complex gave positive signals, the species-specific PCR systems targeting B. mallei (fliP-IS407A) and B. pseudomallei (orf11)-the OIE recommended targets-resulted in negative signals. However, the presence of B. mallei in these tissues was confirmed with a recently described B. mallei-specific real-time PCR system and genot...
Greenwood S, Chow-Lockerbie B, Epp T, Knight C, Wachoski-Dark G, MacDonald-Dickinson V, Wobeser B.Equus caballus papillomavirus type-2 (EcPV-2) has been proposed as a causal factor in equine genital squamous cell carcinoma (SCC). This study had 2 objectives: first, calculate the frequency of papillomavirus (PV) and EcPV-2 infection in papillomas, carcinomas in situ (CIS), and SCCs in Western Canadian horses; and second, determine if EcPV-2 status of equine SCCs is associated with overall survival (OS). EcPV-2 status of 115 archived tissue samples, spanning 6 years, was determined using broad spectrum (MY09/11) and EcPV-2-specific polymerase chain reaction (PCR) assays, EcPV-2-E6/E7 chromog...
Myers R, Cembran A, Fernandez-Funez P.Prion diseases are a group of neurodegenerative diseases endemic in humans and several ruminants caused by the misfolding of native prion protein (PrP) into pathological conformations. Experimental work and the mad-cow epidemic of the 1980s exposed a wide spectrum of animal susceptibility to prion diseases, including a few highly resistant animals: horses, rabbits, pigs, and dogs/canids. The variable susceptibility to disease offers a unique opportunity to uncover the mechanisms governing PrP misfolding, neurotoxicity, and transmission. Previous work indicates that PrP-intrinsic differences (s...
Peters S, Wilson J, Boyette J.The objective of this study was to determine the influence of age on expression of insulin-like growth factor 1 (IGF1), insulin-like growth factor binding protein (IGFBP5), myostatin (MSTN), and myosin (MYH1) genes which are related to growth and muscle development in the American Quarter Horse. Thus, horses (n = 10) from weanling, yearling, 2-, 3-, and 10-year-old age classes were sampled and gene expression was assessed by RT-qPCR. ΔC was calculated using the hypoxanthine-guanine phosphoribosyltransferase gene as an internal normalizer. The generalized linear model was used to determine di...
Löfgren M, Larsson P, Lindberg R, Hörnaeus K, Tydén E.Mild, moderate and severe equine asthma is a problem for equine welfare. The aetiology of the disease is not known in detail but is likely multi-factorial. One important factor may be inhaled dust which carries harmful substances which may be bioactivated and thus can lead to local inflammation in the airways. The aim of this study was to investigate gene expression and protein localisation of cytochrome P450 (CYP) enzymes, superoxide dismutase and glutathione-S-transferases (GST) involved in bioactivation and detoxification of harmful substances in lungs of horses with or without histological...
Ekici S, Ozmen O.The active roles of microribonucleic acids (miRNAs) in gene regulation have made miRNAs a key point for the scientific world in the study of physiological processes. Although saliva includes the largest number of miRNAs, there is no miRNA study in saliva on horses has been found. Our study is the first study on miRNAs isolation from saliva in horses. In the present study, saliva was studied in Arabian racehorses to better understand the molecular mechanisms of expression levels that are effective in lipid metabolism of miRNAs and their target genes during the race. Identification of lipid meta...
Tozaki T, Ohnuma A, Takasu M, Nakamura K, Kikuchi M, Ishige T, Kakoi H, Hirora KI, Tamura N, Kusano K, Nagata SI.Gene doping has raised concerns in human and equestrian sports and the horseracing industry. There are two possible types of gene doping in the sports and racing industry: (1) administration of a gene-doping substance to postnatal animals and (2) generation of genetically engineered animals by modifying eggs. In this study, we aimed to identify genetically engineered animals by whole-genome resequencing (WGR) for gene-doping control. Transgenic cell lines, in which the erythropoietin gene (EPO) cDNA form was inserted into the genome of horse fibroblasts, were constructed as a model of genetica...
Fontanel M, Todd E, Drabbe A, Ropka-Molik K, Stefaniuk-Szmukier M, Myćka G, Velie BD.Arabian horses are not only one of the most ancient breeds in the world, but they are also one of the most appreciated racehorse breeds today. The breed generates attention for their phenomenal endurance ability and their capability for gallop racing. Consequently, genetic testing to select the best individuals is attracting ever increasing interests from the Arabian industry. As such, the aim of this study was to further investigate associations between performance and variation at candidate genes suspected of having a key role in Arabian gallop racing performance. Generalized linear models w...
Todd ET, Thomson PC, Hamilton NA, Ang RA, Lindgren G, Viklund Å, Eriksson S, Mikko S, Strand E, Velie BD.Domestic animal populations are often characterised by high rates of inbreeding and low effective population sizes due to selective breeding practices. These practices can result in otherwise rare recessive deleterious alleles drifting to high frequencies, resulting in reduced fertility rates. This study aimed to identify potential recessive lethal haplotypes in the Thoroughbred horse breed, a closed population that has been selectively bred for racing performance. In this study, we identified a haplotype in the LY49B gene that shows strong evidence of being homozygous lethal, despite having h...
Semik-Gurgul E.Sarcoids are the most commonly diagnosed skin tumours in equines. Bovine papillomaviruses (BPVs) are the primary causative agent of sarcoids. There has been intensive research to discover the molecular mechanisms that may contribute to the aetiopathogenesis of this disease and tumour suppressors and proto-oncogenes known to play a role in human neoplastic conditions have been investigated in equine sarcoids. Current approaches include the identification of gene expression profiles, characterising sarcoid and normal skin tissues, and an assessment of epigenetic alterations such as microRNA diff...
Curi RA, Pereira GL, Alvarez MVN, Baldassini WA, Machado Neto OR, Chardulo LAL.The main objectives of this study were to identify and functionally classify SNPs and indels by exome sequencing of animals of the racing line of Quarter Horses. Based on the individual genomic estimated breeding values (GEBVs) for maximum speed index (SImax) obtained for 349 animals, two groups of 20 extreme animals were formed. Of these individuals, 20 animals with high GEBVs for SImax and 19 with low GEBVs for SImax had their exons and 5' and 3' UTRs sequenced. Considering SNPs and indels, 105 182 variants were identified in the expressed regions of the Quarter Horse genome. Of these, 72 ...
Asadollahpour Nanaei H, Esmailizadeh A, Ayatollahi Mehrgardi A, Han J, Wu DD, Li Y, Zhang YP.Body size is considered as one of the most fundamental properties of an organism. Due to intensive breeding and artificial selection throughout the domestication history, horses exhibit striking variations for heights at withers and body sizes. Debao pony (DBP), a famous Chinese horse, is known for its small body size and lives in Guangxi mountains of southern China. In this study, we employed comparative population genomics to study the genetic basis underlying the small body size of DBP breed based on the whole genome sequencing data. To detect genomic signatures of positive selection, we ap...
Edwards L, Finno CJ.Neurologic disease in horses can be particularly challenging to diagnose and treat. These diseases can result in economic losses, emotional distress to owners, and injury to the horse or handlers. To date, there are 5 neurologic diseases caused by known genetic mutations and several more are suspected to be heritable: lethal white foal syndrome, lavender foal syndrome, cerebellar abiotrophy, occipitoatlantoaxial malformation, and Friesian hydrocephalus. Genetic testing allows owners, breeders, and veterinarians to make informed decisions when selecting dams and sires for breeding or deciding t...
Valberg SJ.There are 5 single-gene mutations that are known to cause muscle disease in horses. These mutations alter the amino acid sequence of proteins involved in cell membrane electrical conduction, muscle energy metabolism, muscle contraction, and immunogenicity. The clinical signs depend on the pathway affected. The likelihood that an animal with a mutation will exhibit clinical signs depends on the mode of inheritance, environmental influences, and interactions with other genes. Selection of a genetic test for use in diagnostic or breeding decisions requires a knowledge of clinical signs, mode of i...
Littiere TO, Castro GHF, Rodriguez MDPR, Bonafé CM, Magalhães AFB, Faleiros RR, Vieira JIG, Santos CG, Verardo LL.Integration of genomic data with gene network analysis can be a relevant strategy for unraveling genetic mechanisms. It can be used to explore shared biological processes between genes, as well as highlighting transcription factors (TFs) related to phenotypes of interest. Unlike other species, gene-TF network analyses have not yet been well applied to horse traits. We aimed to (1) identify candidate genes associated with horse performance via systematic review, and (2) build biological processes and gene-TF networks from the identified genes aiming to highlight the most candidate genes for hor...
Krajaejun T, Kittichotirat W, Patumcharoenpol P, Rujirawat T, Lohnoo T, Yingyong W.Genome sequences are a vital resource for accelerating the biological exploration of an organism of interest. Pythium destruens (a synonym of Pythium insidiosum) causes a difficult-to-treat infectious disease called pythiosis worldwide. Detection and management of pythiosis are challenging. Basic knowledge of the disease is lacking. Genomes of this organism isolated from different continents (i.e., Asia and the Americas) have been sequenced and publicly available. Here, we sequenced the genome of an Australian isolate of P. destruens. Genome data will facilitate the comparative analysis of thi...
Futas J, Oppelt J, Janova E, Musilova P, Horin P.Natural killer (NK) cells play important roles in innate and adaptive immunity, as well as in the reproduction of placental mammals. Ly49 (KLRA) molecules represent a lectin-like type of NK cell receptor encoded within a complex genomic region, the NK cell complex. In rodents and horses, an expansion of the genes encoding Ly49 receptors leading to the formation of a gene family was observed. High sequence similarities and frequent high polymorphism of multiple family members represent an obstacle both for their individual identification and for annotation in the reference genomes of their resp...
Williams ZJ, Velez-Irizarry D, Petersen JL, Ochala J, Finno CJ, Valberg SJ.Myofibrillar myopathy (MFM) of unknown aetiology has recently been identified in Warmblood (WB) horses. In humans, 16 genes have been implicated in various MFM-like disorders. Objective: To identify variants in 16 MFM candidate genes and compare allele frequencies of all variants between MFM WB and non-MFM WB and coding variants with moderate or severe predicted effects in MFM WB with publicly available data of other breeds. To compare differential gene expression and muscle fibre contractile force between MFM and non-MFM WB. Methods: Case-control. Methods: 8 MFM WB, 8 non-MFM WB, 33 other WB,...
Dahlgren AR, Tablin F, Finno CJ.Genetic bleeding disorders can have a profound impact on a horse's health and athletic career. As such, it is important to understand the mechanisms of these diseases and how they are diagnosed. These diseases include haemophilia A, von Willebrand disease, prekallikrein deficiency, Glanzmann's Thrombasthenia and Atypical Equine Thrombasthenia. Exercise-induced pulmonary haemorrhage also has a proposed genetic component. Genetic mutations have been identified for haemophilia A and Glanzmann's Thrombasthenia in the horse. Mutations are known for von Willebrand disease and prekallikrein deficienc...
Bao T, Han H, Li B, Zhao Y, Bou G, Zhang X, Du M, Zhao R, Mongke T, Laxima , Ding W, Jia Z, Dugarjaviin M, Bai D.Skeletal muscle is the largest organ system in the mammalian body and plays a key role in locomotion of horses. Fast and slow muscle fibers have different abilities and functions to adapt to exercises. To investigate the RNA and miRNA expression profiles in the muscles with different muscle fiber compositions on Mongolian horses. We examined the muscle fiber type population and produced deep RNA sequencing for different parts of skeletal muscles. And chose two of them with the highest difference in fast and slow muscle fiber population (splenius and gluteus medius) for comparing the gene expre...
Harty RN, Caughman GB, Holden VR, O'Callaghan DJ.Equine herpesvirus 1 (EHV-1, Kentucky A strain) preparations enriched for defective interfering particles (DIPs) can readily establish persistent infection. The UL1 gene, which is conserved in the genome of DIPs that mediate persistent infection, maps between nucleotides 1418 and 2192 (258 amino acids) from the L (long) terminus. UL1 has no homology with any known gene encoded by herpes simplex virus type 1 but has limited homology to open reading frame 2 of varicella-zoster virus and the "circ" gene of bovine herpesvirus type 1. Previous work showed that the EHV-1 UL1 gene belongs to the earl...
Gulati BR, Deepa R, Singh BK, Rao CD.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...
Jun J, Cho YS, Hu H, Kim HM, Jho S, Gadhvi P, Park KM, Lim J, Paek WK, Han K, Manica A, Edwards JS, Bhak J.The horse (Equus ferus caballus) is one of the earliest domesticated species and has played an important role in the development of human societies over the past 5,000 years. In this study, we characterized the genome of the Marwari horse, a rare breed with unique phenotypic characteristics, including inwardly turned ear tips. It is thought to have originated from the crossbreeding of local Indian ponies with Arabian horses beginning in the 12th century. Results: We generated 101 Gb (~30 × coverage) of whole genome sequences from a Marwari horse using the Illumina HiSeq2000 sequencer. The seq...
Mapes S, Rhodes DM, Wilson WD, Leutenegger CM, Pusterla N.Fifty-five isolates of Escherichia coli from septicaemic neonatal foals were used to validate five real-time pcr assays targeting different known virulence factor genes: curli fibre (csgD), ferric hydroxamate uptake (fhuA), type 1A pilin (fimA), aerobactin (lutA) and yersiniabactin (fyuA). A pcr assay targeting a universal sequence of the bacterial 16S rrna gene served as quality control. The pcr assays showed good analytical specificity and sensitivity on the basis of sequencing the pcr products, their lack of cross-reactivity with non-E coli organisms, high amplification efficiency and a lim...
Griffith OW, Brandley MC, Whittington CM, Belov K, Thompson MB.In oviparous amniotes (reptiles, birds, and mammals) the chorioallantoic membrane (CAM) lines the inside of the egg and acts as the living point of contact between the embryo and the outside world. In livebearing (viviparous) amniotes, communication during embryonic development occurs across placental tissues, which form between the uterine tissue of the mother and the CAM of the embryo. In both oviparous and viviparous taxa, the CAM is at the interface of the embryo and the external environment and can transfer signals from there to the embryo proper. To understand the evolution of placental ...
Klohonatz KM, Coleman SJ, Islas-Trejo AD, Medrano JF, Hess AM, Kalbfleisch T, Thomas MG, Bouma GJ, Bruemmer JE.Equine maternal recognition of pregnancy (MRP) is a process whose signal remains unknown. During MRP the conceptus and endometrium communicate to attenuate prostaglandin F (PGF) secretion, sparing the corpus luteum and maintaining progesterone production. Recognition of a mobile conceptus by the endometrium is critical by days 14-16 post-ovulation (PO), when endometrium produces PGF, initiating luteolysis. The objective of this study was to evaluate endometrial gene expression changes based upon pregnancy status via RNA sequencing. This experiment utilized a cross-over design with each mare se...
Corbin LJ, Pope J, Sanson J, Antczak DF, Miller D, Sadeghi R, Brooks SA.Novel coat colour phenotypes often emerge during domestication, and there is strong evidence of genetic selection for the two main genes that control base coat colour in horses- and . These genes direct the type of pigment produced, red pheomelanin () or black eumelanin (), as well as the relative concentration and the temporal-spatial distribution of melanin pigment deposits in the skin and hair coat. Here, we describe a genome-wide association study (GWAS) to identify novel genic regions involved in the determination of the shade of bay. In total, 126 horses from five different breeds were r...
Yuan Z, Gault EA, Campo MS, Nasir L.Equine sarcoids represent the most common skin tumours in equids worldwide, characterized by localized invasion, rare regression and high recurrence following surgical intervention. Bovine papillomavirus type 1 (BPV-1) and less commonly BPV-2 are now widely recognized as the causative agents of the disease. Fibroblasts isolated from sarcoids are highly invasive. Invasion is associated with a high level of viral gene expression and matrix metalloproteinase upregulation. However, it remains unclear to what extent BPV-1 proteins are involved in the transformation of equine cells. To address this ...
The Journal of heredityNovember 5, 1997
Volume 88, Issue 5 384-392 doi: 10.1093/oxfordjournals.jhered.a023123
Allen WR, Short RV.Equids possess the unusual ability to interbreed freely among the phenotypically and karyotypically diverse member species of the genus to produce viable, but usually infertile, offspring. The mule (female horse x male donkey) was humanity's first successful attempt at genetic engineering and its clear expression of both parental phenotypes has contributed much to our understanding of genetic inheritance over the centuries. Even more surprising, mares and donkeys have been shown to be capable of carrying to term a range of true, xenogeneic extraspecies pregnancies created by embryo transfer, i...
Mansour TA, Scott EY, Finno CJ, Bellone RR, Mienaltowski MJ, Penedo MC, Ross PJ, Valberg SJ, Murray JD, Brown CT.Transcriptome interpretation relies on a good-quality reference transcriptome for accurate quantification of gene expression as well as functional analysis of genetic variants. The current annotation of the horse genome lacks the specificity and sensitivity necessary to assess gene expression especially at the isoform level, and suffers from insufficient annotation of untranslated regions (UTR) usage. We built an annotation pipeline for horse and used it to integrate 1.9 billion reads from multiple RNA-seq data sets into a new refined transcriptome. This equine transcriptome integrates eight d...
Lohmann KL, Vandenplas ML, Barton MH, Bryant CE, Moore JN.Lipopolysaccharide (LPS) antagonists inhibit the response of inflammatory cells to LPS, presumably by competitive inhibition, and may be of therapeutic value in the treatment of endotoxemia and sepsis. The inhibitory effects of some LPS antagonists are restricted to certain host species, however, as the same molecules can have significant endotoxic activity in other species. This species-specific recognition appears to be mediated by Toll-like receptor 4 (TLR4) and/or MD-2. We have shown previously that LPS from Rhodobacter sphaeroides ( RsLPS) is an LPS antagonist in human cells but an agonis...
Meehan M, Nowlan P, Owen P.Cell-wall-associated proteins from Streptococcus equi subsp. equi, the causative agent of strangles, were analysed with a view to identifying a potential protective antigen. Preparations of these proteins, isolated from mutanolysin extracts of cell walls, were shown to contain one major high-M(r) protein species (apparent M(r) 220,000 and 550,000 when analysed by SDS-PAGE and gel-filtration chromatography, respectively). The high-M(r) protein bound horse fibrinogen and was purified under non-denaturing conditions using fibrinogen affinity chromatography. The fibrinogen-binding protein (FgBP) r...
Detournay O, Morrison DA, Wagner B, Zarnegar B, Wattrang E.This study aimed at identifying all of the type I interferon (IFN) genes of the horse and at monitoring their expression in equine cells on in vitro induction. We identified 32 putative type I IFN loci on horse chromosome 23 and an unplaced genomic scaffold. A phylogentic analysis characterized these into 8 different type I IFN classes, that is, putative functional genes for 6 IFN-α, 4 IFN-β, 8 IFN-ω (plus 4 pseudogenes), 3 IFN-δ (plus 1 pseudogene), 1 IFN-κ and 1 IFN-ε, plus 1 IFN-ν pseudogene, and 3 loci belonging to what has previously been called IFN-αω. Our analyses indicate that...
Moon S, Lee JW, Shin D, Shin KY, Kim J, Choi IY, Kim J, Kim H.Using next-generation sequencing, we conducted a genome-wide scan of selective sweeps associated with selection toward genetic improvement in Thoroughbreds. We investigated potential phenotypic consequence of putative candidate loci by candidate gene association mapping for the finishing time in 240 Thoroughbred horses. We found a significant association with the trait for Ral GApase alpha 2 (RALGAP2) that regulates a variety of cellular processes of signal trafficking. Neighboring genes around RALGAP2 included insulinoma-associated 1 (INSM1), pallid (PLDN), and Ras and Rab interactor 2 (RIN2)...
Wallis N, Raffan E.Obesity is one of the most prevalent health conditions in humans and companion animals globally. It is associated with premature mortality, metabolic dysfunction, and multiple health conditions across species. Obesity is, therefore, of importance in the fields of medicine and veterinary medicine. The regulation of adiposity is a homeostatic process vulnerable to disruption by a multitude of genetic and environmental factors. It is well established that the heritability of obesity is high in humans and laboratory animals, with ample evidence that the same is true in companion animals. In this r...
DARLINGTON RW, RANDALL CC.Equine abortion virus was purified from the plasma of infected golden Syrian hamsters by differential centrifugation and nuclease treatment. The preparations were essentially free of nonviral elements on electron microscopic examination, and sedimentation in sucrose and potassium tartrate density gradients resulted in a single visible band. Electron microscopy of this band showed it to be composed of viral particles, and injection into hamsters resulted in infection and death of the animals. The viral particles had a sedimentation coefficient of approximately 2200 S and a hydrated density of 1...
Pusterla N, Madigan JE, Chae JS, DeRock E, Johnson E, Pusterla JB.We report successful helminthic transmission of Ehrlichia risticii, the causative agent of Potomac horse fever, using trematode stages collected from Juga yrekaensis snails. The ehrlichial agent was isolated from the blood of experimentally infected horses by culture in murine monocytic cells and identified as E. risticii ultrastructurally and by characterization of three different genes.
Rajpar I, Barrett JG.Tendon injury is a significant clinical problem due to poor healing and a high reinjury rate; successful treatment is limited by our poor understanding of endogenous tendon stem cells. Recent evidence suggests that adult stem cells are phenotypically diverse, even when comparing stem cells isolated from the same tissue from the same individual, and may in fact exist on a spectrum of proliferation and differentiation capacities. Additionally, the relationships between and clinical relevance of this phenotypic variation are poorly understood. In particular, tenogenic capacity has not been studie...
Higuchi RG, Wrischnik LA, Oakes E, George M, Tong B, Wilson AC.Sequences are reported for portions of two mitochondrial genes from a domestic horse and a plains zebra and compared to those published for a quagga and a mountain zebra. The extinct quagga and plains zebra sequences are identical at all silent sites, whereas the horse sequence differs from both of them by 11 silent substitutions. Postmortem changes in quagga DNA may account for the two coding substitutions between the quagga and plains zebra sequences. The hypothesis that the closest relative of the quagga is the domestic horse receives no support from these data. From the extent of sequence ...
Terry RB, Archer S, Brooks S, Bernoco D, Bailey E.A single autosomal dominant locus, leopard complex (LP) controls the presence of appaloosa pigmentation patterns in the horse. The causative gene for LP is unknown. This study was undertaken to map LP in the horse. Two paternal half sib families segregating for the LP locus and including a total of 47 offspring were used to perform a genome scan which localized LP to horse chromosome 1 (ECA1). LP was linked to ASB08 (LOD = 9.99 at Theta = 0.02) and AHT21 (LOD = 5.03 at Theta = 0.14). To refine the map position of LP, eight microsatellite markers on ECA1 (UM041, LEX77, 1CA41, TKY374, COR046, 1C...
Cvitas I, Oberhänsli S, Leeb T, Dettwiler M, Müller E, Bruggman R, Marti EI.Insect bite hypersensitivity (IBH) is a Th-2, IgE-mediated dermatitis of horses caused by bites of insects of the genus Culicoides that has common features with human atopic dermatitis. Together with Th-2 cells, the epithelial barrier plays an important role in development of type I hypersensitivities. In order to elucidate the role of the epithelial barrier and of the skin immune response in IBH we studied the transcriptome of lesional whole skin of IBH-horses (IBH-LE; n = 9) in comparison to non-lesional skin (IBH-NL; n = 8) as well as to skin of healthy control horses (H; n = 9). To study t...
Burger D, Thomas S, Aepli H, Dreyer M, Fabre G, Marti E, Sieme H, Robinson MR, Wedekind C.Genes of the major histocompatibility complex (MHC) have been shown to influence social signalling and mate preferences in many species, including humans. First observations suggest that MHC signalling may also affect female fertility. To test this hypothesis, we exposed 191 female horses () to either an MHC-similar or an MHC-dissimilar stimulus male around the time of ovulation and conception. A within-subject experimental design controlled for non-MHC-linked male characteristics, and instrumental insemination with semen of other males ( = 106) controlled for potential confounding effects of ...
White SH, Johnson SE, Bobel JM, Warren LK.Untrained Thoroughbred horses (6 mares and 6 geldings; 11 yr [SE 1] and 565 kg [SE 11]) were used to evaluate antioxidant gene expression and enzyme activity in blood and skeletal muscle in response to prolonged exercise after receiving 2 levels of dietary selenium for 36 d: 0.1 (CON; = 6) or 0.3 mg/kg DM (SEL; = 6). Horses were individually fed 1.6% BW coastal bermudagrass hay, 0.4% BW whole oats, and a mineral/vitamin premix containing no Se. Sodium selenite was added to achieve either 0.1 or 0.3 mg Se/kg DM in the total diet. On d 35, horses underwent 2 h of submaximal exercise in a free-st...
Pedersen PJ, Thomsen KB, Olander ER, Hauser F, Tejada Mde L, Poulsen KL, Grubb S, Buhl R, Calloe K, Klaerke DA.The KCNH2 and KCNE2 genes encode the cardiac voltage-gated K+ channel KV11.1 and its auxiliary β subunit KCNE2. KV11.1 is critical for repolarization of the cardiac action potential. In humans, mutations or drug therapy affecting the KV11.1 channel are associated with prolongation of the QT intervals on the ECG and increased risk of ventricular tachyarrhythmia and sudden cardiac death--conditions known as congenital or acquired Long QT syndrome (LQTS), respectively. In horses, sudden, unexplained deaths are a well-known problem. We sequenced the cDNA of the KCNH2 and KCNE2 genes using RACE an...
The Journal of heredityAugust 18, 2015
Volume 106, Issue 6 734-740 doi: 10.1093/jhered/esv062
Jäderkvist Fegraeus K, Johansson L, Mäenpää M, Mykkänen A, Andersson LS, Velie BD, Andersson L, Árnason T, Lindgren G.Previous studies showed a positive effect of the DMRT3 "gait keeper" mutation on harness racing performance in Standardbreds, French-, and Nordic trotters. The mutation has also been shown to influence riding traits in multiple breeds. This study investigated the effect of the DMRT3 mutation on harness racing performance and riding traits in Finnhorses. Finnhorses used for harness racing (n = 180) and for riding (n = 59) were genotyped for the DMRT3 mutation. For the trotters the genotypes were evaluated for association with racing performance (number of starts, victories, placings, earnings, ...
Ludwig A, Reissmann M, Benecke N, Bellone R, Sandoval-Castellanos E, Cieslak M, Fortes GG, Morales-Muñiz A, Hofreiter M, Pruvost M.Leopard complex spotting is inherited by the incompletely dominant locus, LP, which also causes congenital stationary night blindness in homozygous horses. We investigated an associated single nucleotide polymorphism in the TRPM1 gene in 96 archaeological bones from 31 localities from Late Pleistocene (approx. 17 000 YBP) to medieval times. The first genetic evidence of LP spotting in Europe dates back to the Pleistocene. We tested for temporal changes in the LP associated allele frequency and estimated coefficients of selection by means of approximate Bayesian computation analyses. Our result...
Gulati BR, Kumar R, Mohanty N, Kumar P, Somasundaram RK, Yadav PS.Tendon injuries are common in race horses, and mesenchymal stem cells (MSCs) isolated from adult and foetal tissue have been used for tendon regeneration. In the present study, we evaluated equine amniotic fluid (AF) as a source of MSCs and standardised methodology and markers for their in vitro tenogenic differentiation. Plastic-adherent colonies were isolated from 12 of 20 AF samples by day 6 after seeding and 70-80% cell confluency was reached by day 17. These cells expressed mesenchymal surface markers [cluster of differentiation (CD)73, CD90 and CD105] by reverse transcription (RT)-polyme...
Han SH, Yang BC, Ko MS, Oh HS, Lee SS.we analyzed the sex chromosome-encoding ZFX-ZFY genes and tested molecular sexing using the amplification patterns of intron 9 of ZFX-ZFY in the horse. Results: the amplification of the ZFX-ZFY produced two distinct patterns, reflecting sexual dimorphism based on a length difference between the X and Y chromosomes. The amplification products from foals showed two distinct bands: one was common to all foals and mares, indicating that this band was amplified from ZFX, while the other was specific to some foals, indicating that it was from ZFY. The result based on the PCR assay was identical to t...
Suliman Y, Becker F, Wimmers K.Poor fertility of breeding stallions is a recognised problem in the equine industry. The aim of the present study was to detect molecular pathways using two groups of stallions that differed in pregnancy rates as well as in the proportion of normal and motile spermatozoa. RNA was isolated from spermatozoa of each stallion and microarray data were analysed to obtain a list of genes for which transcript abundance differed between the groups (P ≤0.05, fold change ≥1.2). In all, there were 437 differentially expressed (DE) genes between the two groups (P ≤ 0.05, fold change ≥1.2). Next, th...
