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.
Lewczuk D, Borowska A, Maśko M, Bagnicka E.: Knowledge of the genetic background of evaluated traits has been the basis for genetic progress in every horse-breeding population and is essential for precise breeding and up-to-date decision-making. The study aimed to estimate the heritability coefficients for field performance traits in mares. : The research was based on 1408 evaluations of mares conducted during the years 2002-2021 in 51 training centers in Poland. The preliminary analyses of the effects, significant for the investigated traits, were obtained using analysis of variance, and these additional data are also presented (SAS p...
Santana ML, Bignardi AB, Faria RAS, Silva JAIV.Thermal load is a major welfare and performance concern for athletic horses, as physical exertion increases internal heat production. Although several phenotypic strategies have been developed to mitigate its effects, the genetic basis of thermal tolerance in horses remains largely unexplored. This study aimed to (1) evaluate the influence of thermal indices on the racing performance of Brazilian Quarter Horses, and (2) investigate the genetic basis of thermal tolerance through the estimation of genetic parameters across temperature gradients. We analyzed 21,857 racing-time (RT) records from 5...
Ricard A, Deretz S, Menard C, Priest BDS.The objective was to evaluate the genetic relationship between the surface temperature of regions of interest, measured using infrared images of young horses and functional longevity in jumping. This relationship was assessed by comparing the temperatures measured in the offspring of two groups of sires, one favourable and one unfavourable, to longevity. The study used a specific data collection protocol on a sample of 921 young progeny, before they began competing, of 141 extreme stallions, comprising 61 favourable and 80 unfavourable sires. These stallions had been selected based on estimate...
Ludwig A, Biermann R, Frölich K, Jandowsky A, Langner C, Lieckfeldt D, Tschann K, Reissmann M.Domestic Baroque donkeys are popular animals in many European parks and zoos. Although their cream coat color is very charismatic, the underlying genetics is still undiscovered. Addressing this question, a candidate approach was used to search for the causative mutation.Considering the knowledge from domestic horses, the () was identified as the most promising candidate. Samples from 77 domesticated donkeys, 11 wild equids, 1 mule and 2 domestic horses were included in comparison. All exons and the flanking intron sequences of the were sequenced (2774bp).Sequence comparison revealed that a m...
Taned M, Zandi MB, Salek Ardestani S, Abdoli M, Spangler ML.Race performance in Thoroughbred horses is influenced by both genetic and environmental factors. Understanding their genetic architecture is essential for designing effective breeding programs. Objective: This study aimed to estimate genetic parameters and trends for key performance traits in Iranian Thoroughbred racehorses. Methods: Performance data, including race completion time (RCT), rank at the end of the competition (REC), and average speed (AS), were obtained from the Iranian Equestrian Federation (2002-2021). Pedigree data from 14,391 individuals were analyzed using CFC software. Gene...
Encina A, Sánchez-Guerrero MJ, Ligero M, RodrÃguez-Sainz de Los Terreros A, Valera M.White leg markings in horses are phenotypic traits influenced by genetic and environmental factors. This study analyzed their prevalence, symmetry, and genetic parameters in 38,825 Pura Raza Española (PRE) horses registered in the official studbook. White markings were scored using a binary (affected/unaffected) and a four-level ordinal scale. Most horses (38,341 out of 38,825; 98.8%) had at least one limb without white markings. The prevalence of white markings was higher in the hindlegs (17.9% LH; 14.5% RH) than in the forelegs (5.3% LF; 4.6% RF). Markings were most frequent above the fetlo...
Simonin EM, Torsteinsdóttir S, Svansson V, Björnsdóttir S, Freer H, Tarsillo J, Wagner B.The origins of allergy are both genetic and environmental. We performed a full-sibling study to determine the role of early-in-life or delayed allergen introduction on hypersensitivity development in a cohort with history of an allergic phenotype and Culicoides hypersensitivity. IgE-mediated allergies naturally develop in many mammalian species, and we used a horse model of allergy called hypersensitivity. hypersensitivity is a seasonal, recurrent, IgE-mediated allergy caused by the salivary proteins of biting midges. Unassigned: The study included four cohorts that lived together in the s...
Steensma MJ, Doekes HP, Derks MFL, Ducro BJ.In Friesian horses, withers height is an important trait as a minimum has been set to be eligible to the studbook. Several loci for withers height have been identified in horses. However, withers height has not been studied in the Friesian horse. Therefore, our aim was to identify loci associated with withers height in the Friesian horse population. We performed a genome-wide association study using 70 K SNP data of 2192 Friesian horses. We found ECA1 and ECA9 to be significantly associated with withers height, explaining 19.6% and 3.5% of the phenotypic variance, respectively. In other hors...
Kingsley NB, Sandmeyer L, Dwyer A, Langefeld CD, McMullen RJ, McCue M, Lassaline M, Bellone RR.Equine recurrent uveitis (ERU), an inflammatory eye disease, is the leading cause of blindness among horses. Insidious uveitis, a form of ERU, is especially pervasive within the Appaloosa breed and is highly heritable (h = 0.68-1.0). To date only one risk locus, leopard complex (LP), has been identified, and it explained 0.16-0.33 of the heritability estimate, suggesting that insidious uveitis is a complex genetic disease within the Appaloosa horse breed with multiple unknown predisposing loci. Results: A genome-wide association study (GWAS) using relatedness, LP genotype, sex, and age as ...
Seeger MG, de Vargas APC, Vogel FSF, Cargnelutti JF.Streptococcus equi subsp. equi (S. equi) is the etiological agent of strangles, a contagious equine disease characterized by lymph node abscess and respiratory complications. To clarify the epidemiology and virulence factors of isolates, this study demonstrated phenotypic and genotypic differences between S. equi obtained from nasal secretions and lymph node aspirates of clinical strangles cases. Additionally, circulating alleles were differentiated through sequencing of the 5' end of the seM gene. A total of 23 clinical isolates collected from horses with strangles over the past decade were a...
Karlau A, Azcona F, Molina A, Trigo P, Sánchez-Serrano JP, Demyda-Peyrás S.The Peruano de Paso is a horse breed renowned for its smooth gait, traditionally selected based on breeders' empirical knowledge. Recently, the frequency of chestnut horses, a recessive trait, has increased substantially within the official studbook. This study evaluated whether preference for chestnut coat colour has influenced morphological traits and genetic diversity within the breed. A total of 8376 records of seven morphological traits, collected by the Peruano de Paso Breeders Association over eight years, were analysed, along with a pedigree including 41,357 individuals. Morphological ...
Van Buren SL, Petersen JL, Brown CT, Finno CJ.With advancing genomic technologies, single-nucleotide polymorphism (SNP) arrays and whole genome sequencing (WGS) have become essential tools in equine genetic research. In this study, we assessed the concordance in SNP calls and trait-mapping efficacy by comparing data of 21 horses both genotyped on the Equine 670 K SNP array and sequenced at either ~12× or ~30× depth. Our analysis revealed that higher sequencing depths were significantly associated with fewer discordant calls between platforms. Additionally, we investigated the most frequent no-call and discordant positions and identifi...
Everts RE, Caron R, Foster G, McLoone K, Simiele L, Martin K, Brooks SA, Lafayette C.Roan coat color is described as the dispersion of white hairs within an otherwise solid background-color coat. This phenotype is primarily expressed on the body of the horse, with the head and legs exhibiting few or no white hairs. Previous studies mapped the locus for roan to the region and observed linked variants in a small number of breeds. Recently, we reported evidence for two independent haplotypes, and , in the region, which account for approximately 38% and 36% of roan horses, respectively. In the current report, using whole genome sequencing for unknown roan samples. We present a ...
Staiger EA, Pereira de Toledo A, Rizzato Paschoal V, Patterson Rosa L.Horse gaits are a trait highly selected and prized in diverse breeds. Meanwhile, gait classification relies mostly on subjective visual observations by evaluators. Noninvasive equipment able to track locomotion in horses and output quantitative gait parameters is not only helpful in evaluating locomotion but also in designating gait types and its variations. Equine locomotion pattern designation based solely on observer evaluation can be subjective; therefore, utilizing tools that provide quantitative results and track individual limb movements, especially during intermediate-speed gaits, can ...
Werle J, Nunes GT, Machado CS, Silva CBD, Vogel FSF, Vargas APC, Cargnelutti JF.The genus Corynebacterium encompasses versatile bacteria that act as natural microbiota or pathogens, causing infections in humans and animals, including equine reproductive disorders. Corynebacterium uterequi (C. uterequi) is a potential pathogen in mares, associated with reproductive disorders including endometritis, embryonic loss, and infertility, raising concerns for equine reproductive health. This study aimed to characterize C. uterequi isolates from mares in southern Brazil and deepen the understanding of this species. Phenotypic, molecular, and phylogenetic analyses were performed on ...
Everts RE, Caron R, Foster G, McLoone K, Martin K, Brooks SA, Lafayette C.The roan coat color is described as the dispersion of white hairs within an otherwise solid background color coat. This phenotype is primarily expressed on the body of the horse, with the head and legs exhibiting few to no white hairs. Previous studies mapped the locus for roan to the KIT region and observed linked variants in a small number of breeds. However, utilizing those linked markers to determine the roan genotype in other breeds has seen limited success. In this communication we identify a second roan allele (RN2) which, in conjunction with a previously observed roan allele (RN1) disc...
Obradovic NA, McFadden A, Martin K, Vierra M, McLoone K, Martin E, Thomas A, Everts RE, Brooks SA, Lafayette C.This paper reports three novel KIT variants likely responsible for previously unexplained white patterning phenotypes observed in three groups of horses. White spots and markings may have substantial consequences on the value and health of domesticated horses. This study aims to elucidate the genetic mechanisms underlying depigmented coat colors to aid in producing prosperous herds. Aligned whole genome sequences were manually screened to identify three polymorphisms in a family of Anglo-Arabian horses (N = 7), a family of Warmblood horses (N = 5), and a single stock-type mare with unexplained...
Dash SK, Panda S, Karna DK, Mishra C, Kalaignazhal G.The present study aimed to identify significant morphometric traits in Malkangiri ponies of Odisha through principal component analysis. The data were collected randomly from 200 ponies aged more than five years and 13 morphometric traits alongwith three indices were recorded. The mean height at wither, height at croup, body length, chest girth, punch girth, height at forearm, height at hock, fetlock to coronet, chest width, neck circumference, poll to wither, wither to croup and croup to head of the tail were 126.7 ± 0.39, 122.6 ± 0.29, 107.9 ± 0.2, 122 ± 0.31, 118.6 ±â...
Santana ML, Franco TGB, Bignardi AB.Barrel racing is a competitive timed rodeo event that challenges horses and riders to complete a cloverleaf pattern around three barrels in the fastest time possible. In this study, we aimed to estimate the genetic parameters of barrel racing time (BRT) and evaluate the most suitable statistical model for its analysis. We compared a repeatability model and three random regression models (RRM) to analyse the longitudinal BRT data in Brazilian Quarter Horses. A total of 356,877 BRT records from 14,108 horses that competed in various events held across Brazil between 2010 and 2024 were analysed. ...
Stefaniuk-Szmukier M, Bieniek A, Ropka-Molik K, Bellone RR.Congenital stationary night blindness (CSNB) has been connected to the leopard complex spotting phenotype (LP) in various horse breeds. CSNB associated with LP is thought to be caused by a 1378 bp insertion in TRPM1, with homozygotes being nightblind and having few to no spots of pigment in their white patterned area. This study aimed to assess the prevalence of CSNB alleles in tarant-colored horses in Poland through a three-primer system for an allele-specific Polymerase Chain Reaction (PCR). The TRPM1 gene insertion was genotyped in 221 horses belonging to Małopolska, Felin and Shetland Pon...
Kabir A, Kelley WG, Glover C, Erol E, Helmy YA.Salmonella is a foodborne pathogen that poses a significant threat to global public health. It affects several animal species, including horses. Salmonella infections in horses can be either asymptomatic or cause severe clinical illness. Infections caused by Salmonella are presently controlled with antibiotics. Due to the formation of biofilms and the emergence of antimicrobial resistance, the treatment has become more complicated. Our study focused on investigating the prevalence of Salmonella enterica in necropsied horses, assessing the capability for biofilm formation, and motility, determi...
Nazari-Ghadikolaei A, Fikse WF, Viklund Ã…G, Mikko S, Eriksson S.Swedish Warmblood horses (SWB) are bred for show jumping and/or dressage with young horse test scores as indicator traits. This study aimed to investigate possible candidate genes and regions of importance for evaluated and linearly scored young horse test traits. A single-step genome-wide association study (ssGWAS) was done using the BLUPF90 suite of programs for factors scores from factor analysis of traits assessed at young horse tests together with height at withers. The ssGWAS included 20,814 SWB with factors scores for four factors for evaluated traits. A total of 6436 of these horses al...
An T, Dugarjaviin M, Han H.The Mongolian horse, one of the oldest and most genetically diverse breeds, exhibits a wide variety of coat colors and patterns, including both wild-type and unique features. A notable characteristic of dun Mongolian horses is the presence of Bider markings-symmetrical, black-mottled patterns observed on the shoulder blades. These markings are also seen in Przewalski's horses. The dun coat color, a common wild-type phenotype in domestic horses, is characterized by pigment dilution with distinct dark areas and is regulated by mutations in the gene. This study aimed to investigate the role of ...
Liu YK, Fu WW, Wang ZY, Pei SW, Li KH, Wu WW, Le MZ, Yue XP.Chakouyi (CKY) horses from the Qinghai‒Xizang Plateau are well known for their unique lateral gaits and high-altitude adaptation, but genetic mechanisms underlying these phenotypes remain unclear. This study presents a comparison of 60 newly resequenced genomes of gaited CKY horses with 139 public genomes from 19 horse breeds. Population structure analyses (admixture, PCA, and neighbor-joining tree) reveal a close genetic relationship between CKY and other highland breeds (Tibetan and Chaidamu horses). Compared with other Chinese breeds, CKY horses present reduced nucleotide diversity (θπ)...
Yoshihara T, Tozaki T, Nakaya S, Takasu M, Kawate K, Furukawa R, Kikuchi M, Isihge T, Nagata SI, Kakoi H, Hobo S.The Taishu horse is a native Japanese breed threatened with extinction. It is important to genotype the causative genes of rare phenotypes in endangered breeds because unique genetic traits might be lost unless a breeding strategy for conservation is constructed. In the present study, nine single-nucleotide variants and three indels of nine genes related to coat color, body composition, and gait were genotyped in 56 Taishu horses. Of these, only three genes were polymorphic. The observed coat color phenotypes coincided with the estimated phenotype from the genotypes, whereas black horses showe...
Parsad R, Bagiyal M, Ahlawat S, Arora R, Gera R, Chhabra P, Sharma U.Donkeys (Equus asinus) have played a vital role in agriculture, transportation, and companionship, particularly in developing regions where they are indispensable working animals. The domestication of donkeys marked a significant turning point in human history, as they became essential for transportation, agriculture, and trade, especially in arid and semi-arid areas where their resilience and endurance were highly valued. In modern society, donkeys are indispensable due to their diversified applications, including meat, dairy, medicine, and functional bioproducts, supporting economic, cultura...
Van Mol B, Janssens S, Oosterlinck M, Pille F, Buys N.Equine osteochondrosis and osteochondral fragments in the fetlock joint are linked to various environmental and genetic risk factors. To assess the scope of the literature linking these risk factors to the development of these osteochondral disorders, while identifying knowledge gaps and challenges to guide future research, a scoping review was performed. This article constitutes the second part of this scoping review and focuses on genetic factors, with the first part addressing environmental factors. To identify potentially relevant papers, online bibliographical databases PubMed and Web of ...
Rosengren Pielberg G, Golovko A, Sundström E, Curik I, Lennartsson J, Seltenhammer MH, Druml T, Binns M, Fitzsimmons C, Lindgren G, Sandberg K....In horses, graying with age is an autosomal dominant trait associated with a high incidence of melanoma and vitiligo-like depigmentation. Here we show that the Gray phenotype is caused by a 4.6-kb duplication in intron 6 of STX17 (syntaxin-17) that constitutes a cis-acting regulatory mutation. Both STX17 and the neighboring NR4A3 gene are overexpressed in melanomas from Gray horses. Gray horses carrying a loss-of-function mutation in ASIP (agouti signaling protein) had a higher incidence of melanoma, implying that increased melanocortin-1 receptor signaling promotes melanoma development in Gra...
Makvandi-Nejad S, Hoffman GE, Allen JJ, Chu E, Gu E, Chandler AM, Loredo AI, Bellone RR, Mezey JG, Brooks SA, Sutter NB.Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS) that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many...
Petersen JL, Mickelson JR, Rendahl AK, Valberg SJ, Andersson LS, Axelsson J, Bailey E, Bannasch D, Binns MM, Borges AS, Brama P, da Câmara Machado A....Intense selective pressures applied over short evolutionary time have resulted in homogeneity within, but substantial variation among, horse breeds. Utilizing this population structure, 744 individuals from 33 breeds, and a 54,000 SNP genotyping array, breed-specific targets of selection were identified using an F(ST)-based statistic calculated in 500-kb windows across the genome. A 5.5-Mb region of ECA18, in which the myostatin (MSTN) gene was centered, contained the highest signature of selection in both the Paint and Quarter Horse. Gene sequencing and histological analysis of gluteal muscle...
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...
Signer-Hasler H, Flury C, Haase B, Burger D, Simianer H, Leeb T, Rieder S.The molecular analysis of genes influencing human height has been notoriously difficult. Genome-wide association studies (GWAS) for height in humans based on tens of thousands to hundreds of thousands of samples so far revealed ∼200 loci for human height explaining only 20% of the heritability. In domestic animals isolated populations with a greatly reduced genetic heterogeneity facilitate a more efficient analysis of complex traits. We performed a genome-wide association study on 1,077 Franches-Montagnes (FM) horses using ∼40,000 SNPs. Our study revealed two QTL for height at withers on c...
Marklund L, Moller MJ, Sandberg K, Andersson L.The melanocyte-stimulating hormone receptor gene (MC1R) is the major candidate gene for the chestnut coat color in horses since it is assumed to be controlled by an allele at the extension locus. MC1R sequences were PCR amplified from chestnut (e/e) and non-chestnut (E/-) horses. A single-strand conformation polymorphism was found that showed a complete association to the chestnut coat color among 144 horses representing 12 breeds. Sequence analysis revealed a single missense mutation (83Ser-->Phe) in the MC1R allele associated with the chestnut color. The substitution occurs in the second ...
Hill EW, Gu J, Eivers SS, Fonseca RG, McGivney BA, Govindarajan P, Orr N, Katz LM, MacHugh DE.Variants of the MSTN gene encoding myostatin are associated with muscle hypertrophy phenotypes in a range of mammalian species, most notably cattle, dogs, mice, and humans. Using a sample of registered Thoroughbred horses (n = 148), we have identified a novel MSTN sequence polymorphism that is strongly associated (g.66493737C>T, P = 4.85x10(-8)) with best race distance among elite racehorses (n = 79). This observation was independently validated (P = 1.91x10(-6)) in a resampled group of Thoroughbreds (n = 62) and in a cohort of Thoroughbreds (n = 37, P = 0.0047) produced by the same trainer...
Vidal MA, Kilroy GE, Lopez MJ, Johnson JR, Moore RM, Gimble JM.To characterize equine adipose tissue-derived stromal cell (ASC) frequency and growth characteristics and assess of their adipogenic and osteogenic differentiation potential. Methods: In vitro experimental study. Methods: Horses (n=5; aged, 9 months to 5 years). Methods: Cell doubling characteristics of ASCs harvested from supragluteal subcutaneous adipose tissue were evaluated over 10 passages. Primary, second (P2), and fourth (P4) passage ASCs were induced under appropriate conditions to undergo adipogenesis and osteogenesis. Limit dilution assays were performed on each passage to determine ...
Hauswirth R, Haase B, Blatter M, Brooks SA, Burger D, Drögemüller C, Gerber V, Henke D, Janda J, Jude R, Magdesian KG, Matthews JM, Poncet PA....During fetal development neural-crest-derived melanoblasts migrate across the entire body surface and differentiate into melanocytes, the pigment-producing cells. Alterations in this precisely regulated process can lead to white spotting patterns. White spotting patterns in horses are a complex trait with a large phenotypic variance ranging from minimal white markings up to completely white horses. The "splashed white" pattern is primarily characterized by an extremely large blaze, often accompanied by extended white markings at the distal limbs and blue eyes. Some, but not all, splashed white...
Tetens J, Widmann P, Kühn C, Thaller G.A genome-wide association scan for loci affecting withers height was conducted in 782 German Warmblood stallions, which were genotyped using the Illumina EquineSNP50 Bead Chip. A principal components approach was applied to correct for population structure. The analysis revealed a single major QTL on ECA3 explaining ~18 per cent of the phenotypic variance, which is in concordance with recent reports from other horse populations. The LCORL/NCAPG locus represents a strong candidate gene for this QTL. This locus is among a small number that have consistently been identified to influence human hei...
Brunberg E, Andersson L, Cothran G, Sandberg K, Mikko S, Lindgren G.The Silver coat color, also called Silver dapple, in the horse is characterized by dilution of the black pigment in the hair. This phenotype shows an autosomal dominant inheritance. The effect of the mutation is most visible in the long hairs of the mane and tail, which are diluted to a mixture of white and gray hairs. Herein we describe the identification of the responsible gene and a missense mutation associated with the Silver phenotype. Results: Segregation data on the Silver locus (Z) were obtained within one half-sib family that consisted of a heterozygous Silver colored stallion with 34...
Carrade DD, Owens SD, Galuppo LD, Vidal MA, Ferraro GL, Librach F, Buerchler S, Friedman MS, Walker NJ, Borjesson DL.The development of an allogeneic mesenchymal stem cell (MSC) product to treat equine disorders would be useful; however, there are limited in vivo safety data for horses. We hypothesized that the injection of self (autologous) and non-self (related allogeneic or allogeneic) MSC would not elicit significant alterations in physical examination, gait or synovial fluid parameters when injected into the joints of healthy horses. Methods: Sixteen healthy horses were used in this study. Group 1 consisted of foals (n = 6), group 2 consisted of their dams (n = 5) and group 3 consisted of half-siblings ...
Koolhaas JM, Van Reenen CG.This paper will argue that understanding animal welfare and the individual vulnerability to stress-related disease requires a fundamental understanding of functional individual variation as it occurs in nature as well as the underlying neurobiology and neuroendocrinology. Ecological studies in feral populations of mice, fish, and birds start to recognize the functional significance of phenotypes that individually differ in their behavioral and neuroendocrine response to environmental challenge. Recent studies indicate that the individual variation within a species may buffer the species for st...
Taylor SE, Vaughan-Thomas A, Clements DN, Pinchbeck G, Macrory LC, Smith RK, Clegg PD.There is a paucity of data regarding molecular markers that identify the phenotype of the tendon cell. This study aims to quantify gene expression markers that distinguish between tendon fibroblasts and other mesenchymal cells which may be used to investigate tenogenesis. Methods: Expression levels for 12 genes representative of musculoskeletal tissues, including the proposed tendon progenitor marker scleraxis, relative to validated reference genes, were evaluated in matched samples of equine tendon (harvested from the superficial digital flexor tendon), cartilage and bone using quantitative P...
Anderson MA, Whitlock JE, Harwood VJ.Escherichia coli is the most completely characterized prokaryotic model organism and one of the dominant indicator organisms for food and water quality testing, yet comparatively little is known about the structure of E. coli populations in their various hosts. The diversities of E. coli populations isolated from the feces of three host species (human, cow, and horse) were compared by two subtyping methods: ribotyping (using HindIII) and antibiotic resistance analysis (ARA). The sampling effort required to obtain a representative sample differed by host species, as E. coli diversity was consis...
Doan R, Cohen N, Harrington J, Veazey K, Juras R, Cothran G, McCue ME, Skow L, Dindot SV.Copy number variants (CNVs) represent a substantial source of genetic variation in mammals. However, the occurrence of CNVs in horses and their subsequent impact on phenotypic variation is unknown. We performed a study to identify CNVs in 16 horses representing 15 distinct breeds (Equus caballus) and an individual gray donkey (Equus asinus) using a whole-exome tiling array and the array comparative genomic hybridization methodology. We identified 2368 CNVs ranging in size from 197 bp to 3.5 Mb. Merging identical CNVs from each animal yielded 775 CNV regions (CNVRs), involving 1707 protein- and...
De Schauwer C, Piepers S, Van de Walle GR, Demeyere K, Hoogewijs MK, Govaere JL, Braeckmans K, Van Soom A, Meyer E.During recent years, cell-based therapies using mesenchymal stem cells (MSC) are reported in equine veterinary medicine with increasing frequency. In most cases, the isolation and in vitro differentiation of equine MSC are described, but their proper immunophenotypic characterization is rarely performed. The lack of a single marker specific for MSC and the limited availability of monoclonal antibodies (mAbs) for equine MSC in particular, strongly hamper this research. In this study, 30 commercial mAbs were screened with flow cytometry for recognizing equine epitopes using the appropriate posit...
Gurgul A, Jasielczuk I, Semik-Gurgul E, Pawlina-Tyszko K, Stefaniuk-Szmukier M, Szmatoła T, Polak G, Tomczyk-Wrona I, Bugno-Poniewierska M.The genetic differentiation of the current horse population was evolutionarily created by natural or artificial selection which shaped the genomes of individual breeds in several unique ways. The availability of high throughput genotyping methods created the opportunity to study this genetic variation on a genome-wide level allowing detection of genome regions divergently selected between separate breeds as well as among different horse types sharing similar phenotypic features. In this study, we used the population differentiation index (FST) that is generally used for measuring locus-specifi...
Caliari SR, Harley BA.Biomolecular environments encountered in vivo are complex and dynamic, with combinations of biomolecules presented in both freely diffusible (liquid-phase) and sequestered (bound to the extracellular matrix) states. Strategies for integrating multiple biomolecular signals into a biomimetic scaffold provide a platform to simultaneously control multiple cell activities, such as motility, proliferation, phenotype, and regenerative potential. Here we describe an investigation elucidating the influence of the dose and mode of presentation (soluble, sequestered) of five biomolecules (stromal cell-de...
Fortier LA, Nixon AJ, Williams J, Cable CS.To isolate mesenchymal stem cells from adult horses and determine specific monolayer culture conditions required to enhance biochemically and phenotypically defined chondrocytic differentiation. Methods: 2 adult horse bone marrow donors without skeletal or hematologic abnormalities. Methods: Bone marrow was aspirated from the sternebra, and mesenchymal stem cells were isolated by centrifugation and cultured in monolayers. Subcultures were established in 24-well plates on day 13. Culture medium was harvested every 2 days, and culture of 12 of the 24 wells was terminated on day 6 and of the rema...
Imsland F, McGowan K, Rubin CJ, Henegar C, Sundström E, Berglund J, Schwochow D, Gustafson U, Imsland P, Lindblad-Toh K, Lindgren G, Mikko S....Dun is a wild-type coat color in horses characterized by pigment dilution with a striking pattern of dark areas termed primitive markings. Here we show that pigment dilution in Dun horses is due to radially asymmetric deposition of pigment in the growing hair caused by localized expression of the T-box 3 (TBX3) transcription factor in hair follicles, which in turn determines the distribution of hair follicle melanocytes. Most domestic horses are non-dun, a more intensely pigmented phenotype caused by regulatory mutations impairing TBX3 expression in the hair follicle, resulting in a more circu...
Todd ET, Ho SYW, Thomson PC, Ang RA, Velie BD, Hamilton NA.The Thoroughbred horse has played an important role in both sporting and economic aspects of society since the establishment of the breed in the 1700s. The extensive pedigree and phenotypic information available for the Thoroughbred horse population provides a unique opportunity to examine the effects of 300 years of selective breeding on genetic load. By analysing the relationship between inbreeding and racing performance of 135,572 individuals, we found that selective breeding has not efficiently alleviated the Australian Thoroughbred population of its genetic load. However, we found evidenc...
Haase B, Brooks SA, Schlumbaum A, Azor PJ, Bailey E, Alaeddine F, Mevissen M, Burger D, Poncet PA, Rieder S, Leeb T.White coat color has been a highly valued trait in horses for at least 2,000 years. Dominant white (W) is one of several known depigmentation phenotypes in horses. It shows considerable phenotypic variation, ranging from approximately 50% depigmented areas up to a completely white coat. In the horse, the four depigmentation phenotypes roan, sabino, tobiano, and dominant white were independently mapped to a chromosomal region on ECA 3 harboring the KIT gene. KIT plays an important role in melanoblast survival during embryonic development. We determined the sequence and genomic organization of t...
Metzger J, Philipp U, Lopes MS, da Camara Machado A, Felicetti M, Silvestrelli M, Distl O.Copy number variants (CNVs) have been shown to play an important role in genetic diversity of mammals and in the development of many complex phenotypic traits. The aim of this study was to perform a standard comparative evaluation of CNVs in horses using three different CNV detection programs and to identify genomic regions associated with body size in horses. Results: Analysis was performed using the Illumina Equine SNP50 genotyping beadchip for 854 horses. CNVs were detected by three different algorithms, CNVPartition, PennCNV and QuantiSNP. Comparative analysis revealed 50 CNVs that affecte...
Switonski M, Mankowska M, Salamon S.The melanocortin receptor gene family consists of five single-exon members, which are located on autosomes. Three genes (MC2R, MC4R and MC5R) are syntenic in the human, mouse, cattle and dog genomes, while in the pig, the syntenic group comprises MC1R, MC2R and MC5R. Two genes (MC1R and MC4R) have been extensively studied due to their function in melanogenesis (MC1R) and energy control (MC4R). Conservative organisation of these genes in five mammalian species (human, mouse, cattle, pig and dog), in terms of the encoded amino acid sequence, is higher in the case of MC4R compared to MC1R. Polymo...
Braun J, Hack A, Weis-Klemm M, Conrad S, Treml S, Kohler K, Walliser U, Skutella T, Aicher WK.To evaluate the proliferative behavior, telomere length, immunophenotype, and differentiation capacity of equine adipose tissue-derived mesenchymal stem cells (AT-MSCs). Methods: 6 adult racing horses treated for articular Injury but otherwise healthy. Methods: AT-MSCs were Isolated from horses and expanded In Dulbecco modified Eagle medium enriched with fetal bovine serum and antimicrobials. Expression of cell surface antigens and telomere length were Investigated via flow cytometry Differentiation of MSCs Into chondrocytes, osteoblasts, and adipocytes was Induced In vitro by specific stimuli...
Brooks SA, Bailey E.Sabino (SB) is a white spotting pattern in the horse characterized by white patches on the face, lower legs, or belly, and interspersed white hairs on the midsection. Based on comparable phenotypes in humans and pigs, the KIT gene was investigated as the origin of the Sabino phenotype. In this article we report the genetic basis of one type of Sabino spotting pattern in horses that we call Sabino 1, with the alleles represented by the symbols SB1 and sb1. Transcripts of KIT were characterized by reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing cDNA from horses with the g...
Frischknecht M, Jagannathan V, Plattet P, Neuditschko M, Signer-Hasler H, Bachmann I, Pacholewska A, Drögemüller C, Dietschi E, Flury C, Rieder S....The identification of quantitative trait loci (QTL) such as height and their underlying causative variants is still challenging and often requires large sample sizes. In humans hundreds of loci with small effects control the heritable portion of height variability. In domestic animals, typically only a few loci with comparatively large effects explain a major fraction of the heritability. We investigated height at withers in Shetland ponies and mapped a QTL to ECA 6 by genome-wide association (GWAS) using a small cohort of only 48 animals and the Illumina equine SNP70 BeadChip. Fine-mapping re...
