Genomics in horses involves the study and analysis of the horse genome to understand genetic variations and their implications for equine health, performance, and breeding. This field encompasses the identification and mapping of genes associated with specific traits, diseases, and conditions in horses. Techniques such as whole-genome sequencing and genome-wide association studies (GWAS) are employed to explore genetic diversity and inheritance patterns among different horse breeds. Genomics provides insights into hereditary disorders, informs selective breeding practices, and aids in the development of personalized veterinary care. This page compiles peer-reviewed research studies and scholarly articles that explore the applications, methodologies, and findings of genomic research in equine science.
Alzan HF, Knowles DP, Suarez CE.Apicomplexa tick-borne hemoparasites, including Babesia bovis, Babesia microti, and Theileria equi are responsible for bovine and human babesiosis and equine theileriosis, respectively. These parasites of vast medical, epidemiological, and economic impact have complex life cycles in their vertebrate and tick hosts. Large gaps in knowledge concerning the mechanisms used by these parasites for gene regulation remain. Regulatory genes coding for DNA binding proteins such as members of the Api-AP2, HMG, and Myb families are known to play crucial roles as transcription factors. Although the reperto...
Kobayashi D, Isawa H, Ejiri H, Sasaki T, Sunahara T, Futami K, Tsuda Y, Katayama Y, Mizutani T, Minakawa N, Ohta N, Sawabe K.Getah virus (GETV; genus Alphavirus, family Togaviridae) is a mosquito-borne virus known to cause disease in horses and pigs. In 2014, for the first time in ∼30 years, a sudden GETV outbreak occurred among racehorses in Ibaraki, Japan. Two years before this outbreak, we obtained multiple GETV isolates from Culex tritaeniorhynchus mosquitoes collected in Nagasaki, Japan and determined the whole genome sequence of GETV isolate 12IH26. Our phylogenetic analysis of GETV strains revealed that the isolate 12IH26 forms a robust clade with the epidemic strains 14-I-605-C1 and 14-I-605-C2 isolated fr...
Sharma M, Nunez-Garcia J, Kearns AM, Doumith M, Butaye PR, Argudín MA, Lahuerta-Marin A, Pichon B, AbuOun M, Rogers J, Ellis RJ, Teale C, Anjum MF.In recent years, there has been an increase in the number of livestock-associated methicillin resistant Staphylococcus aureus (LA-MRSA) clonal complex (CC) 398 recovered from S. aureus isolated animals in the UK. To determine possible origins of 12 LA-MRSA CC398 isolates collected after screening more than a thousand S. aureus animal isolates from the UK between 2013 and 2015, whole genome sequences (WGS) of CC398 European, including UK, and non-European isolates from diverse animal hosts were compared. Phylogenetic reconstruction applied to WGS data to assess genetic relatedness of all 89 iso...
Leegwater PA, Vos-Loohuis M, Ducro BJ, Boegheim IJ, van Steenbeek FG, Nijman IJ, Monroe GR, Bastiaansen JW, Dibbits BW, van de Goor LH, Hellinga I....Inbreeding and population bottlenecks in the ancestry of Friesian horses has led to health issues such as dwarfism. The limbs of dwarfs are short and the ribs are protruding inwards at the costochondral junction, while the head and back appear normal. A striking feature of the condition is the flexor tendon laxity that leads to hyperextension of the fetlock joints. The growth plates of dwarfs display disorganized and thickened chondrocyte columns. The aim of this study was to identify the gene defect that causes the recessively inherited trait in Friesian horses to understand the disease proce...
Pacholewska A, Mach N, Mata X, Vaiman A, Schibler L, Barrey E, Gerber V.MiRNAs regulate multiple genes at the post-transcriptional level and therefore play an important role in many biological processes. It has been suggested that miRNA exported outside the cells contribute to inter-cellular communication. Consequently, circulating miRNAs are of particular interest and are promising biomarkers for many diseases. The number of miRNAs annotated in the horse genome is much lower compared to model organisms like human and mouse. We therefore aimed to identify novel equine miRNAs for tissue types and breed in serum. We analysed 71 small RNA-seq libraries derived from n...
Semik E, Gurgul A, Ząbek T, Ropka-Molik K, Koch C, Mählmann K, Bugno-Poniewierska M.Equine sarcoids are the most commonly detected skin tumours in Equidae. In the present research, a comparative transcriptomic analysis was performed which aimed at looking inside a tumour biology and identification of the expression profile as a potential source of cancer specific genes useful as biomarkers. We have used Horse Gene Expression Microarray data from matched equine sarcoids and tumour-distant skin samples. In total, 901 significantly differentially expressed genes (DEGs) between lesional and healthy skin samples have been identified (fold change ≥ 2; P < 0.05). The la...
Finno CJ, Bordbari MH, Valberg SJ, Lee D, Herron J, Hines K, Monsour T, Scott E, Bannasch DL, Mickelson J, Xu L.Specific spontaneous heritable neurodegenerative diseases have been associated with lower serum and cerebrospinal fluid α-tocopherol (α-TOH) concentrations. Equine neuroaxonal dystrophy (eNAD) has similar histologic lesions to human ataxia with vitamin E deficiency caused by mutations in the α-TOH transfer protein gene (TTPA). Mutations in TTPA are not present with eNAD and the molecular basis remains unknown. Given the neuropathologic phenotypic similarity of the conditions, we assessed the molecular basis of eNAD by global transcriptome sequencing of the cervical spinal cord. Differential...
Librado P, Fages A, Gaunitz C, Leonardi M, Wagner S, Khan N, Hanghøj K, Alquraishi SA, Alfarhan AH, Al-Rasheid KA, Der Sarkissian C, Schubert M....The horse was domesticated only 5.5 KYA, thousands of years after dogs, cattle, pigs, sheep, and goats. The horse nonetheless represents the domestic animal that most impacted human history; providing us with rapid transportation, which has considerably changed the speed and magnitude of the circulation of goods and people, as well as their cultures and diseases. By revolutionizing warfare and agriculture, horses also deeply influenced the politico-economic trajectory of human societies. Reciprocally, human activities have circled back on the recent evolution of the horse, by creating hundreds...
Scott EY, Penedo MCT, Murray JD, Finno CJ.Equine cerebellar abiotrophy (CA) is a hereditary neurodegenerative disease that affects the Purkinje neurons of the cerebellum and causes ataxia in Arabian foals. Signs of CA are typically first recognized either at birth to any time up to 6 months of age. CA is inherited as an autosomal recessive trait and is associated with a single nucleotide polymorphism (SNP) on equine chromosome 2 (13074277G>A), located in the fourth exon of TOE1 and in proximity to MUTYH on the antisense strand. We hypothesize that unraveling the functional consequences of the CA SNP using RNA-seq will elucidate the m...
Gemingguli M, Iskhan KR, Li Y, Qi A, Wunirifu W, Ding LY, Wumaierjiang A.The Kazakh horse is an important old horse breed in Xinjiang. They have contributed greatly to the breeding and improvement of other local horse breeds, yet their genetic diversity and population structure are not well understood. In the present study, we evaluated the genetic diversity of Kazakh horses and their relationship with other horse breeds using the mtDNA D-loop region, Cyt b gene, and a DNA fragment (nps 7974-9963, containing COX3, tRNA-Gly, ND3, and tRNA-Arg). A total of 130 Kazakh horses from 8 populations in China and Kazakhstan were analyzed. A total of 88 haplotypes (haplotype ...
Fedorka CE, Scoggin KE, Woodward EM, Squires EL, Ball BA, Troedsson M.In the horse, breeding induces a transient endometrial inflammation. A subset of mares are unable to resolve this inflammation, and they are considered susceptible to persistent mating-induced endometritis PMIE Select seminal plasma proteins cysteine-rich secretory protein-3 (CRISP-3) and lactoferrin have been shown to affect the innate immune response to sperm in vitro. The objective of this study was to determine whether the addition of CRISP-3 and lactoferrin at the time of insemination had an effect on the mRNA expression of endometrial cytokines in susceptible mares after breeding. Six ma...
Franco MM, Santos JB, Mendonça AS, Silva TC, Antunes RC, Melo EO.The domestication of the Equus genus 5000-6000 years ago has influenced the history of human civilization. As soon as horse and donkey species had been domesticated, they were crossbred, producing humanity's first documented attempt at animal genome manipulation. Since then, the mule (male donkey x female horse) and the reciprocal cross (the hinny, male horse x female donkey) have been the most common equine hybrids in the world. Due to their hybrid vigor, mules and hinnies have been intensively used for carrying loads and people and for tilling the land. Despite their importance, visual disti...
Yang Y, Zheng N, Wang W, Zhao X, Zhang Y, Han R, Ma L, Zhao S, Li S, Guo T, Zang C, Wang J.Glycosylation of proteins has been implicated in various biological functions and has received much attention; however, glycoprotein components and inter-species complexity have not yet been elucidated fully in milk proteins. N-linked glycosylation sites and glycoproteins in milk fat globule membrane (MFGM) fractions were investigated by combining N-glycosylated peptides enrichment and high-accuracy Q Exactive identification, to map the N-glycoproteome profiles in Holstein and Jersey cows, buffaloes, yaks, goats, camels, horses, and humans. A total of 399 N-glycoproteins with 677 glycosylation...
Murgiano L, Waluk DP, Towers R, Wiedemar N, Dietrich J, Jagannathan V, Drögemüller M, Balmer P, Druet T, Galichet A, Penedo MC, Müller EJ....We investigated a family of horses exhibiting irregular vertical stripes in their hair coat texture along the neck, back, hindquarters, and upper legs. This phenotype is termed "brindle" by horse breeders. We propose the term "brindle 1 (BR1)" for this specific form of brindle. In some BR1 horses, the stripes were also differentially pigmented. Pedigree analyses were suggestive of a monogenic X-chromosomal semidominant mode of inheritance. Haplotype analyses identified a 5 Mb candidate region on chromosome X. Whole genome sequencing of four BR1 and 60 nonbrindle horses identified 61 private v...
Rukavian D, Hasanbasic D, Ramic J, Zahirovic A, Ajanovic A, Beganovic K, Durmic-Pasic A, Kalamujic B, Pojskic N.The focus of this study was on genetic diversity of TB horse population raised in B&H. Genomic DNA was genotyped by using 17 microsatellite markers. A total of 103 alleles were detected. The average number of alleles per locus was 6.059 and effective number of alleles was 3.293. Means of observed and expected heterozygosity were calculated 0.645 and 0.696, respectively. The average PIC values was 0.649 and inbreeding coefficient was 0.090. Based on all observed parameters, ASB2 locus showed the highest genetic diversity while locus HMS2 was the least diverse. These results suggest that the pop...
Ma L, Sang M, Zhang J, Zhang S.Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and plays multifunctional roles in the immune system. In the present study, a homolog of TRAIL from the Mongolian horse (named ecTRAIL) was identified and characterized. The 870-bp open reading frame encodes a polypeptide of 289 amino acid residues with a predicted molecular weight of 33.47 kDa and pI of 8.47. The genomic structure of ecTRAIL shares a five-exon/six-intron arrangement similar to its orthologs. Multiple alignments show that ecTRAIL is a type II transmembrane protein with a t...
Pinho MD, Erol E, Ribeiro-Gonçalves B, Mendes CI, Carriço JA, Matos SC, Preziuso S, Luebke-Becker A, Wieler LH, Melo-Cristino J, Ramirez M.The pathogenic role of beta-hemolytic Streptococcus dysgalactiae in the equine host is increasingly recognized. A collection of 108 Lancefield group C (n = 96) or L (n = 12) horse isolates recovered in the United States and in three European countries presented multilocus sequence typing (MLST) alleles, sequence types and emm types (only 56% of the isolates could be emm typed) that were, with few exceptions, distinct from those previously found in human Streptococcus dysgalactiae subsp. equisimilis. Characterization of a subset of horse isolates by multilocus sequence analysis (MLSA) a...
Mentoor JL, Lubisi AB, Gerdes T, Human S, Williams JH, Venter M.We report here the complete genome sequence of a lineage 2 West Nile virus (WNV) strain that resulted in fatal neurological disease in a horse in South Africa. Several recent reports exist of neurological disease associated with lineage 2 WNV in humans and horses in South Africa and Europe; however, there are a lack of sequencing data from recent fatal cases in Southern Africa, where these strains likely originate. A better understanding of the genetic composition of highly neuroinvasive lineage 2 strains may facilitate the identification of putative genetic factors associated with increased v...
Wetmore LA, Pascoe PJ, Shilo-Benjamini Y, Lindsey JC.OBJECTIVE To determine the locomotor response to the administration of fentanyl in horses with and without the G57C polymorphism of the μ-opioid receptor. ANIMALS 20 horses of various breeds and ages (10 horses heterozygous for the G57C polymorphism and 10 age-, breed-, and sex-matched horses that did not have the G57C polymorphism). PROCEDURES The number of steps each horse took was counted over consecutive 2-minute periods for 20 minutes to determine a baseline value. The horse then received a bolus of fentanyl (20 μg/kg, IV), and the number of steps was again counted during consecutive 2-...
Kader A, Liu X, Dong K, Song S, Pan J, Yang M, Chen X, He X, Jiang L, Ma Y.Copy number variation (CNV), an essential form of genetic variation, has been increasingly recognized as one promising genetic marker in the analysis of animal genomes. Here, we used the Equine 70K single nucleotide polymorphism genotyping array for the genome-wide detection of CNVs in 96 horses from three diverse Chinese breeds: Debao pony (DB), Mongolian horse (MG) and Yili horse (YL). A total of 287 CNVs were determined and merged into 122 CNV regions (CNVRs) ranging from 199 bp to 2344 kb in size and distributed in a heterogeneous manner on chromosomes. These CNVRs were integrated with s...
BMC research notesJuly 19, 2016
Volume 9 353 doi: 10.1186/s13104-016-2161-9
Tarlinton RE, Alder L, Moreton J, Maboni G, Emes RD, Tötemeyer S.Toll like receptors are one of the major innate immune system pathogen recognition systems. There is little data on the expression of the TLR10 member of this family in the horse. Results: This paper describes the genetic structure of the Equine TLR10 gene and its RNA expression in a range of horse tissues. It describes the phylogenetic analysis of the Equine TLR1,6,10,2 annotations in the horse genome, firmly identifying them in their corresponding gene clades compared to other species and firmly placing the horse gene with other TLR10 genes from odd-toed ungulates. Additional 3' transcript e...
Leeb T, Müller EJ, Roosje P, Welle M.Molecular genetics has made significant advances in the analysis of hereditary dermatoses during the last several years. Objective: To provide an update on currently available genetic tests for skin diseases of dogs, cats and horses, and to aid the veterinary clinician in the appropriate selection and applications of genetic tests. Methods: The scientific literature on the topic was critically reviewed. The list of known causative variants for genodermatoses and hair morphology traits was compiled by searching the Online Mendelian Inheritance in Animals (OMIA) database. Results: Genetic testin...
Rafati N, Andersson LS, Mikko S, Feng C, Raudsepp T, Pettersson J, Janecka J, Wattle O, Ameur A, Thyreen G, Eberth J, Huddleston J, Malig M, Bailey E....Skeletal atavism in Shetland ponies is a heritable disorder characterized by abnormal growth of the ulna and fibula that extend the carpal and tarsal joints, respectively. This causes abnormal skeletal structure and impaired movements, and affected foals are usually killed. In order to identify the causal mutation we subjected six confirmed Swedish cases and a DNA pool consisting of 21 control individuals to whole genome resequencing. We screened for polymorphisms where the cases and the control pool were fixed for opposite alleles and observed this signature for only 25 SNPs, most of which we...
Tang YD, Zhang X, Na L, Wang XF, Fu LH, Zhu CH, Wang X, Zhou JH.Equine infectious anemia virus (EIAV) is a member of the genus Lentivirus of the family Retroviridae. Horses are the most susceptible equids to EIAV infection and are therefore the primary hosts of this virus. In contrast, infected donkeys do not develop clinically active equine infectious anemia (EIA). This phenomenon is similar to what has been observed with HIV-1, which fails to induce AIDS in non-human primates. Interestingly, Shen et al. developed a donkey-tropic pathogenic virus strain (EIAVDV117, DV117) by serially passaging a horse-tropic pathogenic strain, EIAVLN40 (LN40), in donkeys....
Han H, Mao C, Chen N, Lan X, Chen H, Lei C, Dang R.Kit gene is a genetic determinant of horse white coat color which has been a highly valued trait in horses for at least 2,000 years. Single nucleotide polymorphisms (SNPs) in Kit are of importance due to their strong associations with melanoblast survival during embryonic development. In this study, a mutation analysis of all 21 Kit exons in 14 Chinese domestic horse breeds revealed six SNPs (g.91214T>G, g.143245T>G, g.164297C>T, g.170189C>T, g.171356C>G, and g.171471G>A), which located in 5'-UTR region, intron 6, exon 15, exon 20, intron 20, and exon 21 of the equine Kit gene, respectively. S...
Unger L, Fouché N, Leeb T, Gerber V, Pacholewska A.Circulating miRNAs in body fluids, particularly serum, are promising candidates for future routine biomarker profiling in various pathologic conditions in human and veterinary medicine. However, reliable standardized methods for miRNA extraction from equine serum and fresh or archived whole blood are sorely lacking. We systematically compared various miRNA extraction methods from serum and whole blood after short and long-term storage without addition of RNA stabilizing additives prior to freezing. Time of storage at room temperature prior to freezing did not affect miRNA quality in serum. Fur...
Ghosh M, Cho HW, Park JW, Choi JY, Chung YH, Sharma N, Singh AK, Kim NE, Mongre RK, Huynh D, Jiao ZJ, Do KT, Lee HK, Song KD, Cho BW, Jeong D.The athletic abilities of the horse serve as a valuable model to understand the physiology and molecular mechanisms of adaptive responses to exercise. We analyzed differentially expressed genes in triceps brachii muscle tissues collected from Eonjena Taeyang and Jigusang Seryeok Thoroughbred horses and their co-expression networks in a large-scale RNA-sequence dataset comparing expression before and after exercise. High-quality horse transcriptome data were generated, with over 22 million 90-bp pair-end reads. By comparing the annotations, we found that MYH3, MPZ, and PDE8B genes in Eonjena Ta...
Airas N, Hautaniemi M, Syrjä P, Knuuttila A, Putkuri N, Coulter L, McInnes CJ, Vapalahti O, Huovilainen A, Kinnunen PM.A horse in Finland exhibited generalized granulomatous inflammation and severe proliferative dermatitis. After euthanization, we detected poxvirus DNA from a skin lesion sample. The virus sequence grouped with parapoxviruses, closely resembling a novel poxvirus detected in humans in the United States after horse contact. Our findings indicate horses may be a reservoir for zoonotic parapoxvirus.
Lee SK, Lee JK, Lee I.Equus caballus papillomavirus type 2 (EcPV-2) is implicated in genital neoplasms in horses, including equine penile papillomas, penile intraepithelial neoplasia, and squamous cell carcinoma (SCC). This virus seldom regresses spontaneously and can result in the development of SCC, which may result in significant clinical damage and economic cost. However, the prevalence of this virus is unknown in clinically unaffected horses. The aim of this study was to determine the prevalence of EcPV-2 DNA in genital swabs from healthy horses in the Republic of Korea and to investigate genetic variability w...
Voß K, Tetens J, Thaller G, Becker D.Roan (Rn) horses show a typical seasonal change of color. Their body is covered with colored and white hair. We performed a descriptive statistical analysis of breeding records of Icelandic horses to challenge the hypothesis of roan being lethal in utero under homozygous condition. The roan to non-roan ratio of foals from roan × roan matings revealed homozygous roan Icelandic horses to be viable. Even though roan is known to be inherited in a dominant mode and epistatic to other coat colors, the causative mutation is still unknown. Nevertheless, an association between roan phenotype and the K...
Asadollahpour Nanaei H, Ayatollahi Mehrgardi A, Esmailizadeh A.Equine athletes have a genetic heritage that has been evolved for millions of years, which provides an opportunity to study the genetics of locomotion pattern and performance in mammals. The Hanoverian, a breed originating in Germany, is arguably among the most athletic of horse breeds, as well as possessing a balanced character and beautiful appearance. Here, we compared the whole genomes of Hanoverian with three other horse breeds (Akhal-Teke, Franches-Montagnes, and Standardbred), using the fixation index (Fst) and cross-population composite likelihood ratio (XP-CLR) methods for testing the...
Chapuis RJJ, Becker AAMJ, Dowling PM, Weese JS.Antimicrobial-associated diarrhoea is a common adverse effect of antimicrobial treatment in horses and has been reported following the administration of oral doxycycline. The administration of antimicrobials has also been associated with changes in the equine intestinal microbiota diversity yet has not been explored under doxycycline treatment. Objective: To describe the dynamics of the faecal microbial diversity following a 5-day oral administration of doxycycline in healthy horses with Streptococcus zooepidemicus infected tissue chambers. Methods: Experimental prospective cohort study in a s...
Wnuk M, Bugno-Poniewierska M, Lewinska A, Oklejewicz B, Zabek T, Bartosz G, Słota E.Recently, the old horse has been proposed as a model to study telomere-dependent senescence, immunosenescence and inflamm-aging. In the present paper, we used 80 Hucul and Anglo-Arabian horses divided into 3 age groups (juvenile, adult, old) to evaluate age-dependent changes at the genomic and DNA level and in cell proliferative potential. The level of positive TUNEL cells (both apoptotic and with DNA fragmentation), oxidative DNA damage (8-oxoG immunostaining), sister chromatid exchange and bleomycin-induced chromatid breaks were significantly increased in the combined old group compared to t...
Bartolomé E, Goyache F, Molina A, Cervantes I, Valera M, Gutiérrez JP.A method to quantify the contribution of subpopulations to genetic diversity in the whole population was assessed using pedigree information. The standardization of between- and within-subpopulation mean coancestries was developed to account for the different coat colour subpopulation sizes in the Spanish Purebred (SPB) horse population. The data included 166264 horses registered in the SPB Studbook. Animals born in the past 11 years (1996 to 2006) were selected as the 'reference population' and were grouped according to coat colour into eight subpopulations: grey (64 836 animals), bay (33 633...
Díaz S, Giovambattista G, Dulout FN, Peral-García P.Genetic variation in the equine leucocyte antigen-DRB (ELA-DRB) second exon was investigated using polymerase chain reaction (PCR) amplification, restriction fragment length polymorphism (RFLP) of PCR products (PCR-RFLP) and deoxyribonucleic acid (DNA) sequencing. Eight distinct PCR-RFLP patterns could be identified in the studied Argentine Creole (AC) horses. The number of observed patterns per individual ranged from four to six, thus confirming the presence of multiple DRB copies in AC horses. Three PCR-RFLP alleles and three new sequences were identified. The estimated rates of synonymous a...
Giesecke K, Sieme H, Distl O.Stallion fertility is of high economic importance for the horse industry. The discovery of molecular mechanisms affecting fertility will be facilitated by the horse genome assembly and the development of novel tools for analysing complex genetic traits. Genetic markers in candidate genes, such as CRISP3, SPATA1 and INHBA, in breeding stallions have been associated with pregnancy rate per oestrus in mares. This paper reviews candidate autosomal, X and Y genes for stallion fertility, including genes encoding hormones and their receptors of the hypothalamic-pituitary axis, proteins of the seminal...
Liu Y, Bailey KE, Dyall-Smith M, Marenda MS, Hardefeldt LY, Browning GF, Gilkerson JR, Billman-Jacobe H.The human and domestic animal faecal microbiota can carry various antimicrobial resistance genes (ARGs), especially if they have been exposed to antimicrobials. However, little is known about the ARG profile of the faecal microbiota of healthy foals. A high-throughput qPCR array was used to detect ARGs in the faecal microbiota of healthy foals. Objective: To characterise the faecal microbiota and ARG profiles in healthy Australian foals aged less than 1 month. Methods: Observational study. Methods: The faecal microbiota and ARG profiles of 37 Thoroughbred foals with no known gastrointestinal ...
Kwasnik M, Gora IM, Rola J, Zmudzinski JF, Rozek W.The phylogenetic analysis of influenza virus is based mainly on the variable hemagglutinin or neuraminidase genes. However, some discrete evolutionary trends might be revealed when more conservative genes are considered. We compared all available in GenBank database full length NS sequences of equine influenza virus including Polish isolates. Four nucleotides at positions A202, A237, T672 and A714 and three amino acids at positions H59, K71 and S216 which are also present in A/eq/Pulawy/2006 and A/eq/Pulawy/2008 may be discriminating for the Florida sublineage. Threonine at position 83 seems t...
Grillos AS, Roach JM, de Mestre AM, Foote AK, Kinglsey NB, Mienaltowski MJ, Bellone RR.Warmblood Fragile Foal Syndrome Type 1 (WFFS) is an autosomal recessive disorder reported previously only in warmbloods and thought to be caused by a variant in the gene procollagen-lysine,2-oxoglutarate 5-dioxygenase 1 (PLOD1, c.2032G>A, p.Gly678Arg). Given the presentation of this Thoroughbred case, we hypothesised that a similar genetic mechanism caused this phenotype. Objective: To describe the pathological and genetic findings on a foal presenting to a veterinary practice in the UK with skin lesions similar to other Ehlers-Danlos Syndromes, including those documented for warmbloods with W...
Divers TJ, Tomlinson JE, Tennant BC.Theiler's disease (serum hepatitis) may occur in outbreaks or as single cases of acute hepatitis and is often associated with prior administration of equine-origin biologics approximately 4-10 weeks before the onset of clinical signs. Cases have also been described without any prior administration of blood products. The clinical disease has a low morbidity but high mortality and only adult horses are affected. The course of the disease is short, with horses either dying or completely recovering in a few days. Pathology in affected horses is predominantly centrilobular hepatocyte necrosis with ...
Schrimpf R, Metzger J, Martinsson G, Sieme H, Distl O.In stallions, impaired acrosome reaction (IAR) may often cause subfertility. Single nucleotide polymorphisms (SNPs) within FK506-binding protein (FKBP6) seem to be associated with IAR in stallions. However, their effect on stallion fertility has not yet been quantified. Using whole-genome sequence data of seven stallions, we searched FKBP6 for mutations to perform an association study in Hanoverian stallions with estimated breeding values for the paternal component of the pregnancy rate per oestrus cycle (EBV-PAT) as target trait. Genotyping five exonic mutations within FKBP6 revealed a signif...
Scott EY, Penedo MCT, Murray JD, Finno CJ.Equine cerebellar abiotrophy (CA) is a hereditary neurodegenerative disease that affects the Purkinje neurons of the cerebellum and causes ataxia in Arabian foals. Signs of CA are typically first recognized either at birth to any time up to 6 months of age. CA is inherited as an autosomal recessive trait and is associated with a single nucleotide polymorphism (SNP) on equine chromosome 2 (13074277G>A), located in the fourth exon of TOE1 and in proximity to MUTYH on the antisense strand. We hypothesize that unraveling the functional consequences of the CA SNP using RNA-seq will elucidate the m...
Clegg JB, Goodbourn SE, Braend M.The equine alpha globin gene complex comprises two functional alpha genes and an alpha-like pseudogene arranged in the order 5'-alpha 2-(5kb)-alpha 1-(3kb)-psi alpha-3'. A single (embryonic) zeta-like sequence lies within a 12 kb region 5' to the alpha 2 gene. We have determined the sequence of the alpha 1 gene of the BII haplotype, one of two most common haplotypes (the other being BI) which encode alpha globins with either Tyr (BI) or Phe (BII) at codon 24 in both linked alpha genes. In BI and BII the non-allelic alpha 2 and alpha 1 genes respectively code for Gln or Lys at codon 60, thus ac...
Batcher K, Varney S, Raudsepp T, Jevit M, Dickinson P, Jagannathan V, Leeb T, Bannasch D.LINE-1 is an active transposable element encoding proteins capable of inserting host gene retrocopies, resulting in retro-copy number variants (retroCNVs) between individuals. Here, we performed retroCNV discovery using 86 equids and identified 437 retrocopy insertions. Only 5 retroCNVs were shared between horses and other equids, indicating that the majority of retroCNVs inserted after the species diverged. A large number (17-35 copies) of segmentally duplicated Ligand Dependent Nuclear Receptor Corepressor Like (LCORL) retrocopies were present in all equids but absent from other extant peris...
Otte K, Choudhury D, Charalambous M, Engström W, Rozell B.The equine IGF2 gene has been cloned and characterised. It spans a 9 kb region, which is substantially less than the corresponding human gene. Three coding exons and three untranslated leader exons, all highly homologous to those in other species, were identified. Downstream of the polyadenylation site in exon 6, a dinucleotide repeat sequence was identified. Three putative promoters (P1-P3) were localised in the 5' region of the gene. RNase protection analysis revealed two active promoters in fetal tissues, P2 and P3, whereas P3 was the only promoter active in adult tissues. This represents a...
Home WA, Ford JE, Gibson DM.Analysis of 10 cDNA encoding lambda L chains of horse Ig indicated that this species may employ a relatively small number of variable region (V lambda) genes in the splenic B cell population. The V lambda sequences of all of the cDNA analyzed were closely related (> 88% identity at the nucleotide level) and were characterized by a deletion of the amino acid residue at position 3 compared with V lambda sequences so far described in other species. The 10 V lambda sequences could be grouped into three groups, V lambda 1 to V lambda 3, on the basis of a number of linked substitutions. Sequences...
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...
The Journal of heredityDecember 12, 2021
Volume 113, Issue 3 238-247 doi: 10.1093/jhered/esab070
Esdaile E, Avila F, Bellone RR.American Standardbreds were developed as a harness racing horse breed. The United States Trotting Association closed the studbook in 1973 and implemented a book size cap in 2009. This study aimed to investigate genetic diversity in the American Standardbred after the studbook cap was introduced using short tandem repeats (STRs) and single-nucleotide polymorphisms (SNPs). Sixteen STRs from horses foaled from 2010 to 2015 and their sires and dams (n = 50 621) were utilized to examine allelic richness (Ar), expected heterozygosity (HE), observed heterozygosity (HO), unbiased heterozygosity (HU), ...
Park KD, Kim H, Hwang JY, Lee CK, Do KT, Kim HS, Yang YM, Kwon YJ, Kim J, Kim HJ, Song KD, Oh JD, Kim H, Cho BW, Cho S, Lee HK.Copy number variations (CNVs), important genetic factors for study of human diseases, may have as large of an effect on phenotype as do single nucleotide polymorphisms. Indeed, it is widely accepted that CNVs are associated with differential disease susceptibility. However, the relationships between CNVs and gene expression have not been characterized in the horse. In this study, we investigated the effects of copy number deletion in the blood and muscle transcriptomes of Thoroughbred racing horses. We identified a total of 1,246 CNVs of deletion polymorphisms using DNA re-sequencing data from...
Whalley M, Robertson G, Bell C, Love D, Elphinstone M, Wiley L, Craven D.A homologue of the herpes simplex virus (HSV) glycoprotein D gene has been identified in the genome of equine herpesvirus-1 (EHV-1, equine abortion virus). An open reading frame in the middle of the short unique (US) region is capable of encoding a polypeptide of 402 amino acids that has 26% and 20% of its residues matching pseudorabies virus (PRV) gp50 and HSV-1 gD, respectively. Despite this low level of similarity, the positional identity of six cysteine residues and certain motifs, and the location of the EHV-1 gene, clearly define the EHV-1 polypeptide as one of a family of "gD-like" prot...
Schmitz A, Demmel S, Peters LM, Leeb T, Mevissen M, Haase B.Cytochrome P450 enzymes (CYP450s) represent a superfamily of haem-thiolate proteins. CYP450s are most abundant in the liver, a major site of drug metabolism, and play key roles in the metabolism of a variety of substrates, including drugs and environmental contaminants. Interaction of two or more different drugs with the same enzyme can account for adverse effects and failure of therapy. Human CYP3A4 metabolizes about 50% of all known drugs, but little is known about the orthologous CYP450s in horses. We report here the genomic organization of the equine CYP3A gene cluster as well as a compara...
Campana MG, Stock F, Barrett E, Benecke N, Barker GW, Seetah K, Bower MA.Despite the Icelandic horse enjoying great popularity worldwide, the breed's gene pool is small. This is because of a millennium of isolation on Iceland, population crashes caused by natural disasters and selective breeding. Populations with small effective population sizes are considered to be more at risk of selection pressures such as disease and environmental change. By analysing historic and modern mitochondrial DNA sequences and nuclear coat colour genes, we examined real-time population dynamics in the Icelandic horse over the last 150 years. Despite the small gene pool of this breed, w...
Cai D, Zhu S, Gong M, Zhang N, Wen J, Liang Q, Sun W, Shao X, Guo Y, Cai Y, Zheng Z, Zhang W, Hu S, Wang X, Tian H, Li Y, Liu W, Yang M, Yang J, Wu D....The exceptionally rich fossil record available for the equid family has provided textbook examples of macroevolutionary changes. Horses, asses, and zebras represent three extant subgenera of lineage, while the subgenus is another remarkable lineage ranging from North America to Ethiopia in the Pleistocene. We sequenced 26 archaeological specimens from Northern China in the Holocene that could be assigned morphologically and genetically to , a species representative of . We present the first high-quality complete genome of the lineage, which was sequenced to 13.4× depth of coverage. Radioc...
Ma H, Wu Y, Xiang H, Yang Y, Wang M, Zhao C, Wu C.There are large populations of indigenous horse () in China and some other parts of East Asia. However, their matrilineal genetic diversity and origin remained poorly understood. Using a combination of mitochondrial DNA (mtDNA) and hypervariable region (HVR-1) sequences, we aim to investigate the origin of matrilineal inheritance in these domestic horses. Methods: To investigate patterns of matrilineal inheritance in domestic horses, we conducted a phylogenetic study using 31 mtDNA genomes together with 317 others from the GenBank. In terms of the updated phylogeny, a total of 5,180 horse mit...
Sharman P, Wilson AJ.Several studies over recent decades have reported a lack of contemporary improvement in thoroughbred racehorse speed, despite apparent additive genetic variance and putatively strong selection. More recently, it has been shown that some phenotypic improvement is ongoing, but rates are low in general and particularly so over longer distances. Here we used pedigree-based analysis of 692,534 records from 76,960 animals to determine whether these phenotypic trends are underpinned by genetic selection responses, and to evaluate the potential for more rapid improvement. We show that thoroughbred spe...
Kubacki J, Lechmann J, Fraefel C, Bachofen C.We present the genome sequence of equid alphaherpesvirus 1 (EHV-1) sequenced directly from the nasal swab of a Swiss horse that attended an international equestrian event in Valencia, Spain, the origin of an outbreak of neurological disorders in horses in several European countries in February 2021.
Sharp EL, Farrell HE, Borchers K, Holmes EC, Davis-Poynter NJ.Equid herpesvirus 2 (EHV-2), in common with other members of the subfamily Gammaherpesvirinae, encodes homologues of cellular seven-transmembrane receptors (7TMR), namely open reading frames (ORFs) E1, 74 and E6, which each show some similarity to cellular chemokine receptors. Whereas ORF74 and E6 are members of gammaherpesvirus-conserved 7TMR gene families, E1 is currently unique to EHV-2. To investigate their genetic variability, EHV-2 7TMRs from a panel of equine gammaherpesvirus isolates were sequenced. A region of gB was sequenced to provide comparative sequence data. Phylogenetic analysi...
Li Y, Liu Y, Wang M, Lin X, Li Y, Yang T, Feng M, Ling Y, Zhao C.The Chakouyi horse is an ancient Chinese indigenous horse breed distributed in Gansu Province in northwestern China, and is also one of the key breeds protected by the government. However, the origin of the Chakouyi horse remains unclear. As it is distributed in a key region of the Silk Road, it was speculated that the origin of the Chakouyi horse might involve the foreign horse breeds found along this ancient commercial artery. In this study, whole-genome resequencing data of 12 horse breeds, including both indigenous and foreign horses, were applied to reveal the genetic relationships betwee...
