Phenotype in horses refers to the observable physical and behavioral traits of an individual horse, which result from the interaction of its genetic makeup and environmental influences. These traits include characteristics such as coat color, height, conformation, and temperament. Phenotypic expression is a focal point in equine breeding and management, as it influences performance, health, and suitability for specific disciplines. Research in this area examines the genetic basis of phenotypic traits, the impact of environmental factors, and the interaction between genetics and environment. This page aggregates peer-reviewed research studies and scholarly articles that explore the genetic determinants, environmental effects, and practical implications of phenotypic traits in horses.
Gretler SR, Finno CJ, Kass PH, Knych HK.In humans, the drug metabolizing enzyme CYP2D6 is highly polymorphic resulting in substantial differences in the metabolism of drugs including anti-arrhythmics, neuroleptics, and opioids. The objective of this study was to phenotype a population of 100 horses from five different breeds and assess differences in the metabolic activity of the equine CYP2D6 homolog using codeine as a probe drug. Administration of a probe drug is a common method used for patient phenotyping in human medicine, whereby the ratio of parent drug to metabolite (metabolic ratio, MR) can be used to compare relative enzym...
Poyato-Bonilla J, Sánchez-Guerrero MJ, Cervantes I, Gutiérrez JP, Valera M.Measurements from 13 different morphological traits of importance in the Pura Raza Español (PRE) horse were used to estimate genetic and environmental parameters following a heteroscedastic model in which data were assigned to stallions. Data sets used ranged from 20,610 (height at withers) to 48,486 measurements (length of shoulder), and the number of animals analysed in the pedigrees varied from 17,662 (height at withers) to 23,962 (dorsal-sternal diameter). Results of heritabilities of the traits varied from 0.09 (width of chest and upper neck line) to 0.30 (muscular development). Further,...
Mendoza MN, Schalnus SA, Thomson B, Bellone RR, Juras R, Raudsepp T.Complex structural X chromosome abnormalities are rare in humans and animals, and not recurrent. Yet, each case provides a fascinating opportunity to evaluate X chromosome content and functional status in relation to the effect on the phenotype. Here, we report the first equine case of a complex unbalanced X-autosome rearrangement in a healthy but short in stature Thoroughbred mare. Studies of about 200 cells by chromosome banding and FISH revealed an abnormal 2n = 63,X,der(X;16) karyotype with a large dicentric derivative chromosome (der). The der was comprised of normal Xp material, a palind...
Poyato-Bonilla J, Perdomo-González DI, Sánchez-Guerrero MJ, Varona L, Molina A, Casellas J, Valera M.Inbreeding is caused by mating between related individuals and is associated with reduced fitness and performance (inbreeding depression). Several studies have detected heterogeneity in inbreeding depression among founder individuals. Recently, a procedure was developed to predict hidden inbreeding depression load that is associated with founders using the Mendelian sampling of non-founders. The objectives of this study were to: (1) analyse the population structure and general inbreeding, and (2) test this recent approach for predicting hidden inbreeding depression load for four morphological ...
Silva ILS, Junqueira GSB, Oliveira CAA, Costa RB, DE Camargo GMF.Grullo is a dun dilution on a black coat that is common in the Campolina horse: an autochthonous Brazilian breed. The aims of this case study were to evaluate inconsistencies in grullo coat color registration and to explain their possible causes. A total of 3,270 grullo Campolina horses were evaluated. To confirm the genetic possibility of having grullo animals, the coat color genotypes of parents were inferred by phenotype and compared with those of progeny. A total of 242 horses that were registered as grullos could not have this coat based on their parents' information. Possible explanation...
Müller V, Moraes BDSS, Carvalho IR, Wendt CG, Patten RD, Nogueira CEW.The aim of this study was to estimate the genetic parameters for the morphometric measurements of withers height (WH), thoracic circumference (TC) and cannon bone circumference (CBC) of Criollo horses, stratified for maternal and paternal effects. Statistical genetic design of factor crossings was used to evaluate the offspring of full siblings and half-siblings. Fifty stallions were selected (n = 50) who had been crossed with six mares each (n = 6), to provide 300 parental pairings in which two offspring were born per mare (n = 600). WH in females and TC in males were highly influenced ...
Rivas VN, Magdesian KG, Fagan S, Slovis NM, Luethy D, Javsicas LH, Caserto BG, Miller AD, Dahlgren AR, Peterson J, Hales EN, Peng S, Watson KD....Idiopathic hypocalcemia in Thoroughbred (TB) foals causes tetany and seizures and is invariably fatal. Based upon the similarity of this disease with human familial hypoparathyroidism and occurrence only in the TB breed, we conducted a genetic investigation on two affected TB foals. Familial hypoparathyroidism was identified, and pedigree analysis suggested an autosomal recessive (AR) mode of inheritance. We performed whole-genome sequencing of the two foals, their unaffected dams and four unaffected, unrelated TB horses. Both homozygosity mapping and an association analysis were used to prior...
Zhao R, Yihan W, Zhao Y, Li B, Han H, Mongke T, Bao T, Wang W, Dugarjaviin M, Bai D.Different morphological structures of hairs having properties like defense and camouflage help animals survive in the wild environment. Horse is one of the rare kinds of animals with complex hair phenotypes in one individual; however, knowledge of horse hair follicle is limited in literature and their molecular basis remains unclear. Therefore, the investigation of horse hair follicle morphogenesis and pigmentogenesis attracts considerable interest. Results: Histological studies revealed the morphology and pigment synthesis of hair follicles are different in between four different parts (mane,...
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...
Tanaka Y, Adilbish A, Koyama K, Bayasgalan MO, Horiuchi N, Uranbileg N, Watanabe K, Purevdorj B, Gurdorj S, Banzragch B, Badgar B, Suganuma K....Dourine is a deadly protozoan disease in equids caused by infection with Trypanosoma equiperdum. Neurological signs in the later stage of infection may be caused by peripheral polyneuritis and related axonal degeneration. This neuritis involves T lymphocytes, B lymphocytes, and macrophages, and is observed in cases without obvious neurological signs. However, the pathogenesis of neuritis remains unclear. We identified M2 macrophages and CD8 T cells as the predominant phenotypes in neuritis of dourine-affected horses with or without neurological signs. In contrast, the populations of M1 macroph...
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...
Schmitt S, Stephan R, Huebschke E, Schaefle D, Merz A, Johler S.Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe infections in humans and animals worldwide. Studies elucidating the population structure, staphylococcal cassette chromosome mec types, resistance phenotypes, and virulence gene profiles of animal-associated MRSA are needed to understand spread and transmission. Objective: The objective of this study was to determine 1) clonal complexes and spa types, 2) resistance phenotypes, and 3) virulence/resistance gene profiles of MRSA isolated from animals in Switzerland. Methods: We analyzed 31 presumptive MRSA isolates co...
Brooks SA, Palermo KM, Kahn A, Hein J.The American Paint Horse Association (APHA) records pedigree and performance information for their breed, a stock-type horse valued as a working farm or ranch horse and as a pleasure horse. As the name implies, the breed is also valued for its attractive white-spotting patterns on the coat. The APHA utilizes visual inspections of photographs to determine if coat spotting exceeds threshold anatomical landmarks considered characteristic of desirable patterns. Horses with sufficient white patterning enter the 'Regular' registry, rather than the 'Solid Paint-Bred' division, providing a threshold m...
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...
Mançanares ACF, Cabezas J, Manríquez J, de Oliveira VC, Wong Alvaro YS, Rojas D, Navarrete Aguirre F, Rodriguez-Alvarez L, Castro FO.In mesenchymal stem cells (MSCs), it has been reported that prostaglandin E2 (PGE2) stimulation of EP2 and EP4 receptors triggers processes such as migration, self-renewal, survival, and proliferation, and their activation is involved in homing. The aim of this work was to establish a genetically modified adipose (aMSC) model in which receptor genes EP2 and EP4 were edited separately using the CRISPR/Cas9 system. After edition, the genes were evaluated as to if the expression of MSC surface markers was affected, as well as the migration capacity in vitro of the generated cells. Adipose MSCs we...
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...
Box JR, McGowan CM, Raekallio MR, Mykkänen AK, Carslake H, Karikoski NP.Obesity and insulin dysregulation (ID) predispose horses to laminitis. Determination of management practices or phenotypic markers associated with ID may benefit animal welfare. Objective: Determine ID status of a population of Finnhorses using an oral sugar test (OST) and compare phenotypes and management factors between ID and non-ID Finnhorses. Methods: One hundred twenty-eight purebred Finnhorses ≥3 years of age. Methods: Owners were recruited using an online questionnaire regarding signalment, history, feeding, and exercise of their horses. Selected contributing stables within a prede...
Bellone RR, Avila F.Genetic testing in horses began in the 1960s, when parentage testing using blood group markers became the standard. In the 1990s, parentage testing shifted from evaluating blood groups to DNA testing. The development of genetics and genomics in both human and veterinarian medicine, along with continued technological advances in the last 2 decades, has helped unravel the causal variants for many horse traits. Genetic testing is also now possible for a variety of phenotypic and disease traits and is used to assist in breeding and clinical management decisions. This article describes the genetic ...
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...
Larson EM, Babasyan S, Wagner B.Human IgE-binding monocytes are identified as allergic disease mediators, but it is unknown whether IgE-binding monocytes promote or prevent an allergic response. We identified IgE-binding monocytes in equine peripheral blood as IgE+/MHCIIhigh/CD14low cells that bind IgE through an FcεRI αɣ variant. IgE-binding monocytes were analyzed monthly in Culicoides hypersensitive horses and nonallergic horses living together with natural exposure to Culicoides midges. The phenotype and frequency of IgE-binding monocytes remained consistent in all horses regardless of Culicoides exposure. All horses ...
Roy MM, Norton EM, Rendahl AK, Schultz NE, McFarlane D, Geor RJ, Mickelson JR, McCue ME.An 11G nucleotide repeat in the 3' UTR of FAM174A was recently postulated as a risk allele with a dominant mode of inheritance for equine metabolic syndrome (EMS) and laminitis status in Arabian horses. The objective of this project was to evaluate this hypothesis in a large and diverse across-breed population. A total of 301 ponies, 292 Morgans, 64 Arabians, 49 Tennessee Walking Horses and 59 Quarter Horses were genotyped for six observed G repeat alleles in the FAM174A 3' UTR. Phenotype data included laminitis status, baseline insulin, glucose, non-esterified fatty acids, triglycerides, adip...
Salek Ardestani S, Aminafshar M, Zandi Baghche Maryam MB, Banabazi MH, Sargolzaei M, Miar Y.Natural selection and domestication have shaped modern horse populations, resulting in a vast range of phenotypically diverse breeds. Horse breeds are classified into three types (pony, light, and draft) generally based on their body type. Understanding the genetic basis of horse type variation and selective pressures related to the evolutionary trend can be particularly important for current selection strategies. Whole-genome sequences were generated for 14 pony and 32 light horses to investigate the genetic signatures of selection of the horse type in pony and light horses. In the overlappin...
Wutke S, Benecke N, Sandoval-Castellanos E, Döhle HJ, Friederich S, Gonzalez J, Hallsson JH, Hofreiter M, Lõugas L, Magnell O, Morales-Muniz A....An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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...
Todd ET, Hamilton NA, Velie BD, Thomson PC.Horses produce only one foal from an eleven-month gestation period, making the maintenance of high reproductive rates essential. Genetic bottlenecks and inbreeding can increase the frequency of deleterious variants, resulting in reduced reproductive levels in a population. In this study we examined the influence of inbreeding levels on foaling rate, gestation length and secondary sex ratio in Australian Thoroughbred mares. We also investigated the genetic change in these traits throughout the history of the breed. Phenotypic data were obtained from 27,262 breeding records of Thoroughbred mares...
Frantz LAF, Bradley DG, Larson G, Orlando L.The domestication of animals led to a major shift in human subsistence patterns, from a hunter-gatherer to a sedentary agricultural lifestyle, which ultimately resulted in the development of complex societies. Over the past 15,000 years, the phenotype and genotype of multiple animal species, such as dogs, pigs, sheep, goats, cattle and horses, have been substantially altered during their adaptation to the human niche. Recent methodological innovations, such as improved ancient DNA extraction methods and next-generation sequencing, have enabled the sequencing of whole ancient genomes. These gen...
The Journal of heredityApril 4, 2020
Volume 111, Issue 3 287-293 doi: 10.1093/jhered/esaa009
Magdesian KG, Tanaka J, Bellone RR.Splashed white is a coat color pattern in horses characterized by extensive white patterning on the legs, belly, and face often accompanied by blue eyes and deafness. Three mutations in microphthalmia-associated transcription factor (MITF) and two mutations in Paired Box 3 (PAX3) have been identified that explain splashed white patterns (SW1-SW5). An American Paint Horse stallion with a splashed white phenotype and blue eyes, whose parents were not white patterned, was negative for the 5 known splashed white variants and other known white spotting alleles. This novel splashed white phenotype (...
Gurgul A, Jasielczuk I, Semik-Gurgul E, Pawlina-Tyszko K, Szmatoła T, Polak G, Bugno-Poniewierska M.The current role of the horse as a companion animal resulted in a decrease of interest in breeding and usage of draft horses. This meant that the population of cold-blooded horses in Poland has been dramatically reduced during the last decades. To avoid impoverishment of the gene pool of the local horse population, a conservation program was established which involves draft horses and other local horse breeds. The draft horses bred in Poland can be subdivided in a few horse types of which the most widespread and consolidated are Sztumski and Sokólski horses. These two subpopulations are pheno...
Lopez BS, Hurley DJ, Giancola S, Giguère S, Felippe MJB, Hart KA.The impact of culture conditions on equine monocyte-derived dendritic cells (MoDC) generation has not been fully characterized. We hypothesized that 1) MoDC could be cultured in a commercially available serum-free medium (AIM-V); and 2) that differential culture conditions would influence MoDC viability, yield and phenotype. MoDC generated from adult horses were cultured under variable conditions in a series of experiments. Viability was assessed using trypan blue and propidium iodide staining. Yield was determined by manual hemocytometer counting. Phenotype was assessed by flow cytometric ana...
Shang S, Yu Y, Zhao Y, Dang W, Zhang J, Qin X, Irwin DM, Wang Q, Liu F, Wang Z, Zhang S, Wang Z.Through domestication and human selection, horses have acquired various coat colors, including seven phenotypes: black, brown, dark bay, bay, chestnut, white, and gray. Here we determined the genotypes for melanocortin-1 receptor (MC1R) and agouti signaling protein (ASIP) in 709 horses from 15 breeds. We found that the EEEE genotype frequency at MC1R decreased from dark to light colors (black = 64.5%, brown = 67.5%, dark bay = 47.0%, bay = 16.5%, and chestnut = 0.0%), whereas the AAAA genotype frequency at ASIP increased as coat color lightened (black = 0.0%, brown = 22.9%, dark bay = 69.2%, a...
Morgenthaler C, Diribarne M, Capitan A, Legendre R, Saintilan R, Gilles M, Esquerré D, Juras R, Khanshour A, Schibler L, Cothran G.Curly horses present a variety of curl phenotypes that are associated with various degrees of curliness of coat, mane, tail and ear hairs. Their origin is still a matter of debate and several genetic hypotheses have been formulated to explain the diversity in phenotype, including the combination of autosomal dominant and recessive alleles. Our purpose was to map the autosomal dominant curly hair locus and identify the causal variant using genome-wide association study (GWAS) and whole-genome sequencing approaches. Results: A GWAS was performed using a Bayesian sparse linear mixed model, based ...
Christen G, Gerber V, Dolf G, Burger D, Koch C.The mode of inheritance for susceptibility to equine sarcoid disease (ES) remains unknown. The objectives of this study were to analyse a large sample of the Franches-Montagnes (FM) horse population and investigate the heritability and mode of inheritance for susceptibility to ES. Horses were clinically examined for the presence of sarcoid tumours. A standardized examination protocol and client questionnaire were used and a pedigree- and subsequent segregation-analysis for the ES trait performed. To investigate the mode of inheritance, five models were evaluated and compared in a hierarchical ...
Durgam SS, Altmann NN, Coughlin HE, Rollins A, Hostnik LD.There is increased incidence of tendon disorders and decreased tendon healing capacity in people with diabetes mellitus (DM). Recent studies have also suggested pathological ossification in repair tendon of people with DM. Therefore, the objective of this study is to investigate the effects of insulin supplementation, an important pathophysiologic stimulus of DM, on tendon progenitor cell (TPC) proliferation and in vitro osteogenic capacity. Passage 3 TPCs were isolated from collagenase-digested, equine superficial digital flexor tendons. TPC proliferation was measured via MTT assay after 3 da...
Fraser DG, Bailey E.Single-strand conformational polymorphism (SSCP) gel electrophoresis and DNA sequencing were used to characterize the second exon of the horse DRB homologue as well as to identify eight new DRB alleles. The SSCP gels presented a complex pattern, with phenotypes exhibiting between 4 and 13 bands. The DRB SSCP patterns were studied for two families (6 to 13 bands per pattern). For both families, the patterns showed simple Mendelian inheritance. The polymerase chain reaction products from two individuals possessing homozygous major histocompatibility complex (MHC) alleles by descent were cloned a...
Patterson L, Staiger EA, Brooks SA.The Mangalarga Marchador (MM) is a Brazilian horse breed known for a uniquely smooth gait. A recent publication described a mutation in the DMRT3 gene that the authors claim controls the ability to perform lateral patterned gaits (Andersson et al. 2012). We tested 81 MM samples for the DMRT3 mutation using extracted DNA from hair bulbs using a novel RFLP. Horses were phenotypically categorized by their gait type (batida or picada), as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM). Statistical analysis using the plink toolset (Purcell, 2007) revealed significant a...
McGivney BA, Hernandez B, Katz LM, MacHugh DE, McGovern SP, Parnell AC, Wiencko HL, Hill EW.Durability traits in Thoroughbred horses are heritable, economically valuable and may affect horse welfare. The aims of this study were to test the hypotheses that (i) durability traits are heritable and (ii) genetic data may be used to predict a horse's potential to have a racecourse start. Heritability for the phenotype 'number of 2- and 3-year-old starts' was estimated to be = 0.11 ± 0.02 (n = 4499). A genome-wide association study identified SNP contributions to the trait. The neurotrimin (NTM), opioid-binding protein/cell adhesion molecule like (OPCML) and prolylcarboxypeptidase ...
Veraa S, de Graaf K, Wijnberg ID, Back W, Vernooij H, Nielen M, Belt AJM.Variation in equine caudal cervical spine morphology at C6 and C7 has high prevalence in Warmblood horses and is suspected to be associated with pain in a large mixed-breed group of horses. At present no data exist on the relationship between radiographic phenotype and clinical presentation in Warmblood horses in a case-control study. Objective: To establish the frequency of radiographically visible morphologic variation in a large group of Warmblood horses with clinical signs and compare this with a group without clinical signs. We hypothesised that occurrence of morphologic variation in the ...
Frontiers in geneticsDecember 2, 2021
Volume 12 758366 doi: 10.3389/fgene.2021.758366
Durward-Akhurst SA, Schaefer RJ, Grantham B, Carey WK, Mickelson JR, McCue ME.Genetic variation is a key contributor to health and disease. Understanding the link between an individual's genotype and the corresponding phenotype is a major goal of medical genetics. Whole genome sequencing (WGS) within and across populations enables highly efficient variant discovery and elucidation of the molecular nature of virtually all genetic variation. Here, we report the largest catalog of genetic variation for the horse, a species of importance as a model for human athletic and performance related traits, using WGS of 534 horses. We show the extent of agreement between two commonl...
Laseca N, Demyda-Peyrás S, Valera M, Ramón M, Escribano B, Perdomo-González DI, Molina A.Despite the economic importance of fertility for the horse industry, few efforts have been made to achieve a better understanding of the genetic mechanisms underlying its control. This is probably due to the difficulty of obtaining reliable phenotypes and the complexity of modelling the environmental and management factors. This work is novel in that we propose to use reproductive efficiency (RE) as an indicator of mare fertility. To achieve this, we performed a genome-wide association study in the Pura Raza Español horse aimed at identifying genomic variants, regions, and candidate genes ass...
Ropka-Molik K, Stefaniuk-Szmukier M, Musiał AD, Velie BD.Arabian horses are commonly believed to be one of the oldest and most influential horse breeds in the world. The high financial benefits obtained from races tend to search for genetic markers strongly correlated with the results achieved. To date, the modern approaches such as transcriptome, miRNAome, and metabolome analyses have been used to investigate the genetic background of racing performance as well as endurance capacity in Arabians. The analysis of polymorphisms at the genome level has also been applied to the detection of genetic variants associated with exercise phenotype in the Arab...
Druml T, Dobretsberger M, Brem G.In this experiment, which is based on a cohort of 44 Lipizzan mares from the Austrian state stud farm of Piber, we present new statistical techniques for the analysis of shape and equine conformation using image data. In addition, we examined which strategies and procedures of image processing techniques led to a successful interpretation of the traits implemented in horse breeding programs. A total of 246 two-dimensional anatomical and somatometric landmarks were digitized from standardized photographs, and the variation of shape has been analyzed by the use of generalized orthogonal least-sq...
Larson EM, Babasyan S, Wagner B.Human IgE-binding monocytes are identified as allergic disease mediators, but it is unknown whether IgE-binding monocytes promote or prevent an allergic response. We identified IgE-binding monocytes in equine peripheral blood as IgE+/MHCIIhigh/CD14low cells that bind IgE through an FcεRI αɣ variant. IgE-binding monocytes were analyzed monthly in Culicoides hypersensitive horses and nonallergic horses living together with natural exposure to Culicoides midges. The phenotype and frequency of IgE-binding monocytes remained consistent in all horses regardless of Culicoides exposure. All horses ...
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...
The Journal of heredityApril 4, 2020
Volume 111, Issue 3 287-293 doi: 10.1093/jhered/esaa009
Magdesian KG, Tanaka J, Bellone RR.Splashed white is a coat color pattern in horses characterized by extensive white patterning on the legs, belly, and face often accompanied by blue eyes and deafness. Three mutations in microphthalmia-associated transcription factor (MITF) and two mutations in Paired Box 3 (PAX3) have been identified that explain splashed white patterns (SW1-SW5). An American Paint Horse stallion with a splashed white phenotype and blue eyes, whose parents were not white patterned, was negative for the 5 known splashed white variants and other known white spotting alleles. This novel splashed white phenotype (...
Harman RM, Bihun IV, Van de Walle GR.The prevalence of cutaneous fibroproliferative disorders (CFPDs) is high and almost exclusively occurs in humans (keloids and hypertrophic scars) and horses (exuberant granulation tissue), making the horse a valuable translational model for studies on prevention and treatment of human CFPDs. CFPDs arise as a result of dysregulated wound healing characterized by persistently high levels of cytokines, such as transforming growth factor beta 1 (TGF-β1), that contribute to excessive extracellular matrix deposition, and the physical disorganization of dermal fibroblasts (DF). The mesenchymal strom...
Villagómez DA, Lear TL, Chenier T, Lee S, McGee RB, Cahill J, Foster RA, Reyes E, St John E, King WA.We described the clinical, cytogenetic and molecular findings of 17 clinical equine cases presented for abnormal sexual development and infertility. Six horses with an enlarged clitoris had an XX, SRY-negative genotype, which displayed male-like behavior (adult individuals). Bilateral ovotestes were noted in 2 of those cases, while another case showed increased levels of circulating testosterone. Six horses with a female phenotype, including normal external genitalia, had an XY, SRY-negative genotype. These individuals had small gonads and an underdeveloped internal reproductive tract. Four ho...
Hybridization has been widely practiced in plant and animal breeding as a means to enhance the quality and fitness of the organisms. In domestic equids, this hybrid vigor takes the form of improved physical and physiological characteristics, notably for strength or endurance. Because the offspring of horse and donkey is generally sterile, this widely recognized vigor is expressed in the first generation (F1). However, in the absence of recombination between the two parental genomes, F1 hybrids can be expected to be phenotypically intermediate between their parents which could potentially restr...
Payne SL, Pei XF, Jia B, Fagerness A, Fuller FJ.The molecular clones pSPeiav19 and p19/wenv17 of equine infectious anemia virus (EIAV) differ in env and long terminal repeats (LTRs) and produce viruses (EIAV(19) and EIAV(17), respectively) of dramatically different virulence phenotypes. These constructs were used to generate a series of chimeric clones to test the individual contributions of LTR, surface (SU), and transmembrane (TM)/Rev regions to the disease potential of the highly virulent EIAV(17). The LTRs of EIAV(19) and EIAV(17) differ by 16 nucleotides in the transcriptional enhancer region. The two viruses differ by 30 amino acids i...
Ablondi M, Summer A, Vasini M, Simoni M, Sabbioni A.Horses are nowadays mainly used for sport and leisure purposes, and several local breeds, traditionally used in agriculture, are exposed to the risk of extinction. The long-term survival of local horse breeds depends on strategies to both monitor their genetic diversity and to find their sustainable role in the equine market. Thus, several local horse breeds need to adapt their breeding objective to allow a modernization process. The Bardigiano is an example of such horse breeds; we, therefore, studied the existing evaluation protocol from a genetic standpoint to assess the protocol's suitabil...
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...
Santos WB, Schettini GP, Maiorano AM, Bussiman FO, Balieiro JCC, Ferraz GC, Pereira GL, Baldassini WA, Neto ORM, Oliveira HN, Curi RA.The detection of signatures of selection in genomic regions provides insights into the evolutionary process, enabling discoveries regarding complex phenotypic traits. In this research, we focused on identifying genomic regions affected by different selection pressures, mainly highlighting the recent positive selection, as well as understanding the candidate genes and functional pathways associated with the signatures of selection in the Mangalarga Marchador genome. Besides, we seek to direct the discussion about genes and traits of importance in this breed, especially traits related to the typ...
Holl HM, Pflug KM, Yates KM, Hoefs-Martin K, Shepard C, Cook DG, Lafayette C, Brooks SA.Variations in the SLC45A2 gene are responsible for the dilution phenotypes cream and pearl in domestic horses. Cream dilution is inherited in an incomplete dominant manner, diluting only red in the heterozygous state but both red and black pigments when two alleles are present. The pearl dilution is recessive and dilutes only the red and black pigment in the homozygous state or when paired with a cream allele. Horses that inherit one copy of pearl (C ) and one copy of the dominant cream allele (C ) display a dilution phenotype similar to that of homozygous cream, suggesting that pearl is the ...
de Laat MA, Sillence MN, Reiche DB.Equine endocrinopathic laminitis is common and can be associated with an underlying endocrinopathy, such as equine metabolic syndrome (EMS), pituitary pars intermedia dysfunction (PPID), pasture consumption, or any combination of these factors. Objective: The aim of the study was to improve the risk assessment capabilities of clinicians, and to inform management strategies, for acute endocrinopathic laminitis by prospectively examining the phenotypic, hormonal, and clinical characteristics of the disease in a large cohort. Methods: Privately owned horses and ponies (n = 301) of any age, se...
Gigante A, Bevilacqua C, Cappella M, Manzotti S, Greco F.Articular cartilage defects do not heal. Biodegradable scaffolds have been studied for cartilage engineering in order to implant autologous chondrocytes and help cartilage repair. We tested some new collagen matrices differing in collagen type, origin, structure and methods of extraction and purification, and compared the behavior of human chondrocytes cultured on them. Human chondrocytes were grown for three weeks on four different equine type I collagen matrices, one type I, III porcine collagen matrix and one porcine type II collagen matrix. After 21 days, samples were subjected to histoche...
Jammes M, Cassé F, Velot E, Bianchi A, Audigié F, Contentin R, Galéra P.Osteoarthritis (OA) is a widespread osteoarticular pathology characterized by progressive hyaline cartilage degradation, exposing horses to impaired well-being, premature career termination, alongside substantial financial losses for horse owners. Among the new therapeutic strategies for OA, using mesenchymal stromal cell (MSC)-derived exosomes (MSC-exos) appears to be a promising option for conveying MSC therapeutic potential, yet avoiding the limitations inherent to cell therapy. Here, we first purified and characterized exosomes from MSCs by membrane affinity capture (MAC) and size-exclusio...
Salek Ardestani S, Aminafshar M, Zandi Baghche Maryam MB, Banabazi MH, Sargolzaei M, Miar Y.Natural selection and domestication have shaped modern horse populations, resulting in a vast range of phenotypically diverse breeds. Horse breeds are classified into three types (pony, light, and draft) generally based on their body type. Understanding the genetic basis of horse type variation and selective pressures related to the evolutionary trend can be particularly important for current selection strategies. Whole-genome sequences were generated for 14 pony and 32 light horses to investigate the genetic signatures of selection of the horse type in pony and light horses. In the overlappin...
Hackett CH, Flaminio MJ, Fortier LA.A long-term goal of mesenchymal progenitor cell (MPC) research is to identify cell-surface markers to facilitate MPC isolation. One reported MPC feature in humans and other species is lack of CD14 (lipopolysaccharide receptor) expression. The aim of this study was to evaluate CD14 as an MPC sorting marker. Our hypothesis was that cells negatively selected by CD14 expression would enrich MPC colony formation compared with unsorted and CD14-positive fractions. After validation of reagents, bone marrow aspirate was obtained from 12 horses. Fresh and cultured cells were analyzed by flow cytometry ...
Penny J, Harris P, Shakesheff KM, Mobasheri A.Mesenchymal stem cells (MSCs) are multipotent stem cells that can give rise to a range of connective tissue cells including osteoblasts, chondrocytes and adipocytes. MSCs have been isolated from humans and a variety of animal species including rodents, dogs, horses and rabbits. There is currently no consensus on how these cells are identified and characterized. This is partly due to the lack of standardized specific cell surface markers for MSCs. The aim of this review is to examine the literature on equine MSCs and establish whether there is a well-defined phenotype for these cells. Equine MS...
The Journal of heredityFebruary 21, 2008
Volume 99, Issue 2 130-136 doi: 10.1093/jhered/esm115
Rieder S, Hagger C, Obexer-Ruff G, Leeb T, Poncet PA.White markings and spotting patterns in animal species are thought to be a result of the domestication process. They often serve for the identification of individuals but sometimes are accompanied by complex pathological syndromes. In the Swiss Franches-Montagnes horse population, white markings increased vastly in size and occurrence during the past 30 years, although the breeding goal demands a horse with as little depigmented areas as possible. In order to improve selection and avoid more excessive depigmentation on the population level, we estimated population parameters and breeding value...
