Molecular biology in horses involves the study of molecular processes and genetic mechanisms that underpin equine physiology and health. This field encompasses the analysis of DNA, RNA, proteins, and other biomolecules to understand gene expression, genetic variation, and cellular functions in horses. Techniques such as genomic sequencing, gene expression profiling, and molecular diagnostics are employed to explore topics like hereditary diseases, performance traits, and immune responses in equines. This page assembles peer-reviewed research studies and scholarly articles that investigate the molecular biology of horses, focusing on genetic research, molecular techniques, and their applications in equine science.
Breckenridge WC, Kuksis A.The triglyceride compositions of the milk fats of man, dog, guinea pig, cow, sheep, goat, and horse were compared by gas-liquid chromatography of the intact triglycerides and of the butyl esters of the component fatty acids. The milk fats of man, dog, and guinea pig, which were largely made up of long-chain fatty acids, showed a common pattern with major contributions made by the glycerides with 48-54 acyl carbon atoms. The milk fats of cow, sheep, and goat, which were rich in short-chain acids, showed significant proportions of triglycerides with 28-54 acyl carbon atoms. Horse milk, which con...
Steinhardt J, Hiremath CB.Many of the stability characteristics of horse ferrihemo-globin (Hb+) in acid solutions, such as pH dependence and susceptibility to stabilization by iron ligands, are shared by human ferrihemoglobin, but striking differences between the two proteins exist. The most noticeable is the much greater rate of denaturation of the human protein at all pH values. Other differences include a shift to higher pH in the equi-librium between native and acid-denatured forms, differ-ences in the temperature at which the temperature effect on the equilibrium-pH curve reverses, a complete absence in human Hb+ ...
Weir RC, Porter RR.A study of the chemical structure of the horse immunoglobulins IgG and IgA(T) has shown that the amino acid contents of the peptide chains are very similar. These globulins differ most markedly in the products of papain digestion. IgG gives 3.5s products, whereas IgA(T) gives a 5s fraction and smaller components. This difference appears to be associated with the presence of an additional easily reducible disulphide bond in the Fd fragment of the heavy chain. There is two to three times as much carbohydrate in IgA(T) as in IgG. In both, this is in the heavy chain and in IgA(T) more than half is...
Stefaniuk-Szmukier M, Błaszczak A, Długosz B, Musiał A, Ropka-Molik K.The Silesian horse is a heavy warmblood breed developed in Polish Silesia through the covering of local mares by East Frisian and Oldenburg stallions. Because of its historical significance and genetic heritage, the breed is part of a conservation programme in Poland. One of the genetic disorders of concern in warmblood horses is fragile foal syndrome (FFS), an autosomal recessive disease caused by a mutation in the gene (c.2032G>A). Affected foals either perish in late pregnancy or are born with severe connective tissue abnormalities, leading to early death. As carriers do not exhibit sympto...
Khalil WA, Sharf MI, Derbala MK, Alfattah MA, Hassan MAE, Alhujaili W, El-Harairy MA, Abdelnour SA.Oxidative stress is a major contributor to male infertility. Therefore, fortifying assisted reproductive technology with nanotechnology could enhance sperm preservation. Objective: This study aimed to examine the impact of myo-inositol nano-emulsion (MINE) supplementation in semen extender on sperm quality, redox balance, semen bacteriology, apoptosis, ultrastructure, and acrosome status of chilled stallion semen. Methods: Semen samples were collected and preserved with 0 (MINE0), 1 (MINE1), and 2 (MINE2) mg of MINE/mL of extender. Results: Results revealed that extender fortified with 1 or 2 ...
Bueno VLC, Bastos HBA, Centeno LAM, Schmitt F, Larentis G, Mattos RC, Fiala-Rechsteiner S.The seminal plasma (SP), a fluid originating from the testes, epididymis, and accessory sex glands, represents 98 % of the volume of stallion ejaculate. Metabolomic analysis enables the identification of final products of metabolic pathways, providing insights into reproductive physiology. Objective: This study aimed to investigate the metabolomic profile of stallion seminal plasma and to investigate metabolic differences between stallions with high and low pregnancy rates, in order to identify potential biomarkers associated with fertility. Methods: Twenty-four Criollo stallions, were sampled...
Ramsaran LN, Byron M, Parry S, Lection J, Back B, Grenier J, Cheong SH, Diel de Amorim M.Real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a technique that allows for the semi-quantification of mRNA transcripts present within a tissue of interest. Differences in the relative abundance of mRNA between samples detected by RT-qPCR require normalization with a reference gene or genes whose transcript abundance is stable within the tissue of interest independent of experimental conditions. In the field of equine reproductive studies, ACTB, GAPDH and B2M genes are the most widely used as reference genes for the normalization of RT-qPCR results. However,...
Rychtarova J, Fulka H, Loi P, Fulka J.In the mouse, spermatozoa are highly resistant to DNA damage, even when frozen without cryoprotectants, and can produce offspring when subsequently used for ICSI (intracytoplasmic sperm injection). It is not known whether the same applies to other mammals as well. For example, in the horse, even conventional sperm freezing is still very problematic and frequently leads to sperm immobility. It has, however, never been tested whether sperm immobility also mirrors sperm head DNA damage, and if so, to what extent. In our study, we evaluated the damage to DNA in horse frozen and thawed motile and i...
Mackowski M, Kajdasz A, Laskowska K, Cieslak J.Although serological and genetic studies of equine blood group systems have been conducted for many years, the molecular basis of erythrocyte antigens' variability has remained largely unexplored. In this study, we aimed to elucidate the genetic basis of serological variation within equine blood group K. Using mRNA extracted from peripheral blood samples (n = 100) collected from horses with known serological blood types (Ka or K-), we performed a transcriptome-wide association study (TWAS), which revealed a significantly associated region on equine chromosome 2 (ECA2). A detailed analysis ...
Veit M, Matczuk AK.Equine arteritis virus (EAV) is a positive-stranded RNA virus of the Arteriviridae family. Its GP5/M dimer, the principal component of the viral envelope, mediates virus budding and serves as a key target for neutralizing antibodies. Using AlphaFold3, we predicted the 3D structure of the EAV GP5/M dimer and compared it to its homolog in porcine reproductive and respiratory syndrome virus (PRRSV). Both complexes share a conserved architecture comprising a short ectodomain, three helical transmembrane regions, and a β-sheet-rich endodomain. EAV GP5 features a longer ectodomain with four α-heli...
Li Z, Yu T, Ge L, Lv S, Fu Q, Shi H.Equine herpesvirus type 1 (EHV-1) is a major veterinary pathogen causing significant economic losses in the livestock industry. Despite its impact, effective vaccines and targeted antiviral strategies remain limited, largely due to an incomplete understanding of host factors regulating viral replication and pathogenesis. Unassigned: To systematically identify host genes essential for EHV-1 infection, we established a BHK-21 cell line stably expressing Cas9 and performed a genome-wide CRISPR/Cas9 knockout screen using a pooled lentiviral single-guide RNA library. Significantly enriched candidat...
Verstraete MH, Norris JK, Loux SC, De Spiegelaere W, Carossino M, Daels P, Dini P.The placenta mediates critical interactions between mother and offspring that guide development and impact long-term health. Despite its importance, the cellular organization of the equine (Equus caballus) placenta remains poorly defined. The equine epitheliochorial placenta, characterized by the absence of trophoblast invasion and prominent endocrine activity, provides a unique comparative model for studying placental cellular composition and development. Methods: We applied single-cell RNA sequencing to chorioallantois tissue collected from first-trimester (n = 1) and term (n = 2) equine...
Gentilini F, Ogundipe TG, Turba ME, Romagnoli N, Lambertini C, Pollera C, Cremonesi P, Stancampiano L.Gastrointestinal nematode infections significantly impact equine health and welfare, with rising anthelmintic resistance demanding alternative control strategies. Emerging evidence suggests that parasitic nematodes harbour distinct microbiomes, potentially influencing host-parasite dynamics and parasite survival. This study aimed to characterize and compare the microbiomes of equine gastrointestinal nematodes and their hosts, focusing on differences in composition, diversity, and core microbiota structure across different intestinal sites, nematode subfamilies, and sexes. Faecal and nematode s...
Uprety T, Shaffer CL, Loynachan A, Janes J, Cassone L, Kennedy L, Bryant U, Ruby R, Swan M, Sponseller BT, Adam E, Lubbers B, Erol E.Salmonellosis is a highly contagious, zoonotic disease affecting both animal and human health. Early characterization of emerging Salmonella serotypes and associated antimicrobial resistance patterns are essential for outbreak controls in animals and humans. Between 2018 and 2025, 245 Salmonella enterica subsp. enterica were isolated from both ante-mortem and post-mortem equine cases. The predominant Salmonella serotypes were Typhimurium (83), Newport (28), 1,4,[5],12:i:- (26), Saintpaul (25), Hartford (15), and Mbandaka (12). S. Saintpaul, previously rare in horses, was detected in 21 cases i...
Penzhorn L, Crafford JE, Guthrie AJ.African horse sickness (AHS) is the only equine disease for which the World Organisation for Animal Health (WOAH) gives official disease-free status, given that it poses a major threat to the equine industry. The disease is caused by AHS virus (AHSV; family , taxon species ), which is endemic in sub-Saharan Africa. Reverse-transcription quantitative real-time PCR (RT-qPCR) is a rapid, sensitive detection method used in the diagnosis of AHS and the certification of animals as negative for AHSV for the purpose of movement. Genetic variability of AHSV may influence the accuracy of RT-qPCR detecti...
Mkpuma N, Meseko C, Shittu I, Chukwu C, Afiukwa FN, Iroha IR, Muhammad M, Ogbu O.Equine influenza virus (EIV) H3N8 is a highly contagious respiratory pathogen that poses significant health and economic risks to equids globally. In southeastern Nigeria where equids are sold and slaughtered, limited data exist on EIV epidemiology and circulating lineages. Methods: To address this gap, an active surveillance was conducted between January 2022 and October 2023. A total of 400 nasal swabs were collected from horses and donkeys at slaughterhouses and animal markets. The swabs were screened for equine influenza virus (EIV) using quantitative Reverse-Transcription Polymerase Chain...
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...
Valberg SJ, Williams ZJ, Ames EG, Mickelson JR, Nout-Lomas YS, Landolt G, Sanz M, Gardner K.Equine myotonic dystrophy (eMD) is a rare neuromuscular disorder of undetermined origin marked by muscle hypertrophy and stiffness, dystrophic muscle histopathology, and myotonic discharges. In humans, myotonic dystrophy (DM) arises from trinucleotide repeat expansions in dystrophia myotonica protein kinase (DMPK) (DM1) or tetranucleotide expansions in cellular nucleic acid-binding protein (CNBP) (DM2), which disrupt mRNA processing and induce embryonic splicing patterns across multiple genes. In 6 eMD Quarter Horse types, (2-36 months-of-age) and 8 control Quarter Horses we determined: (1) fi...
Thieulent CJ, Sarkar S, Carossino M, Bhowmik M, Zhu H, Balasuriya UBR.Our laboratory identified the susceptible allelic variant of equine CXCL16 protein (EqCXCL16S) as an entry receptor for equine arteritis virus (EAV). However, EAV has a broad host cell tropism and infects cells that lack EqCXCL16S. Thus, we hypothesized that EAV interacts with other host cell protein(s) that facilitate EAV infection. A virus overlay protein-binding assay in combination with a Far-Western blot from EAV-susceptible equine pulmonary artery endothelial cells (EECs) and equine dermal fibroblasts (E. Derm) identified a 57 kDa protein, present in the membrane fraction of the protein ...
Qin S, Kulabieke T, Mizhamuhan D, Zhang M, Jin M, Abula G, Pi M, Wang H, Zhang Y, Guo Q.Equine theileriosis, caused by the protozoan parasite , represents a significant economic threat to the equine industry. In Xinjiang, China, an endemic area for this disease, systematic research on the genetic diversity of has been notably lacking. The aim of this study was to obtain molecular epidemiological data pertaining to the parasite in selected regions of Xinjiang, China, and analyze the genetic characteristics (including rRNA, , and genes) and genotype distribution patterns of isolates from these regions, providing a scientific basis for developing targeted prevention and control s...
Dorrego A, Olvera-Maneu S, Jose-Cunilleras E, Gago P, Raez A, Rivera B, Oporto A, Gonzalez S, Cruz-Lopez F.The forest fly ) is an obligate haematophagous dipteran insect (order Diptera) that primarily infests horses and may contribute to the circulation of vector-borne pathogens. This study aimed to investigate the presence of , s.l., , and , important vector-borne pathogens of equids, in forest flies collected from horses in endemic areas of Spain. A total of 170 forest flies were collected from 39 equids across four geographical regions in Spain (Segovia, Madrid, Toledo, and Menorca) and blood samples were collected from 27 of these horses. All flies were morphologically and molecularly identifi...
Konstantinović N, Gotić J, Baban M, Csik G, Listeš E, Gagović E, Jurković Žilić D, Arežina I, Šubara G, Čulina FE, Delić N, Višal D....Hemotropic mycoplasmas (hemoplasmas) are uncultivable, cell wall-less bacteria that parasitizeon the surface of red blood cells of mammals, potentially causing anemia and other systemic signs. While widely distributed among domestic and wild animals, their occurrence in equids remains poorly understood, and no species has been identified as host-specific to horses or donkeys. This study presents the first systematic survey of hemoplasmas in equids from southeastern Europe and only the second molecularly confirmed case in horses in Europe. A total of 843 equids (817 horses and 26 donkeys) from ...
Toda J, Miyasaka J, Osako H, Murata K, Yunus M, Amalia R, Soe BK, Sato H.Food poisoning caused by consuming raw horsemeat contaminated with Sarcocystis is a significant public health concern. Two morphotypes of sarcocysts in horsemeat, characterized by upright and folded villar protrusions, are typically identified as Sarcocystis fayeri and S. bertrami, respectively. However, recent molecular studies focusing on the ribosomal RNA gene (rDNA) and mitochondrial cytochrome c oxidase subunit I gene (cox1) have indicated a conspecific relationship between these two morphotypes using a limited number of specimens. To explore further genetic diversity in equid sarcocysts,...
Davoudi N, Behbahani M, Mohabatkar H, Dini G, Bakhshesh M.Equine herpesvirus type 1 (EHV-1) is a globally prevalent equine pathogen responsible for severe respiratory, neurological, and reproductive disorders. Accurate and ultrasensitive detection of EHV-1 is critical for timely disease management. In this study, we report the development of the first G-quadruplex-forming aptamer specifically designed for EHV-1 detection. The aptamer was generated using an in silico approach, and its G-quadruplex conformation was confirmed using circular dichroism (CD) spectroscopy and crystal violet fluorescence assays. Binding affinity and specificity were assessed...
Sharif MB, Mohaseb AF, Orlando L, Saliari K, Kunst GK, Czeika S, Mashkour M, Cucchi T, Peters J, Trixl S, Mohandesan E.The Roman conquest of the northern Alpine foreland in 15 BCE introduced larger-sized horses and hybrid mules to the region. To investigate their genetic profiles and influence on local breeding, we analyzed our previously generated shallow shotgun DNA data from 402 Late Iron Age and Roman equids, supplemented with mitochondrial and nuclear capture data from 40 to 31 equids from the same regions and periods. Late Iron Age and Roman horses exhibit high matrilineal diversity, with unique haplogroups in the latter indicating exogenous animals. The preferred use of male mounts in army service menti...
Luis-Calero M, Marinaro F, Muñoz-García CC, Fernández-Hernández P, Ortiz-Rodríguez JM, Fernández-González R, Pericuesta E, Gutiérrez-Adán A....In vitro embryo production is widely used in equine clinical reproduction; however, its efficiency remains suboptimal due to the undermined developmental competence of in vitro-matured oocytes. In this work, we evaluated the effect of mare preovulatory follicular fluid (PFF) secretome supplementation during in vitro maturation (IVM) of equine oocytes recovered post-mortem. Secretome was isolated from PFF and was added to the IVM medium at concentrations of 20 µg/ml (S20) or 40 µg/ml (S40). The percentage of mature oocytes, as well as embryo cleavage, blastocyst development, and gene expr...
Young ND, Wang T, Ang CS, Lale D, Fuehrer HP, Sumanam SB, Korhonen PK, Chang BCH, Gasser RB. is the most prevalent and pathogenic tapeworm (cestode) of horses worldwide, yet it remains molecularly understudied. Here, we present the mitochondrial and chromosome-scale nuclear genomes and matched somatic proteome for this parasite, establishing the first high-resolution molecular resource for the family Anoplocephalidae. This parasite was first characterised morphologically and then by its mitochondrial genome (size: 13,776 bp). Its complete nuclear genome (size: 372.3 Mb) was assembled and characterised; it encodes 9,711 protein-coding genes, 78.2% of which were functionally annotate...
Milczek-Haduch D, Żmigrodzka M, Kiełbik P, Świderska B, Olędzki J, Witkowska-Piłaszewicz O.Extracellular vesicles (EVs) are promising biomarkers and mediators of intercellular communication, but their isolation from equine biofluids remains challenging. This study compared two isolation workflows-size-exclusion chromatography (SEC) and differential ultracentrifugation followed by SEC (UC + SEC)-to evaluate their efficiency, reproducibility, and the proteomic composition of EVs derived from equine serum and plasma. Blood from six healthy horses was processed to obtain platelet-free plasma and serum. EVs were isolated using SEC or UC + SEC and characterized by transmission ele...
To date, there is extensive scientific evidence affirming that physical exercise plays a fundamental role in both the prevention and treatment of various pathological conditions in humans as well as in animals. It is understood that the advantages of movement and exercise have a multifactorial origin and they depend on a category of bioactive molecules vehicolated by extracellular microvesicles known as exosomes. The exosomes act as potential delivery systems for messages within the organism. These findings have drawn significant attention, leading researchers to further investigate the role o...
Nowicka B, Łopuszyński W, Krajewska-Wędzina M, Biazik A, Sobuś M, Polkowska I, Szacawa E.Gastrointestinal mycobacteriosis in horses is difficult to diagnose because of the pathogen's intracellular nature and the non-specific clinical symptoms. Effective accurate diagnosis facilitates prognosis and treatment. Current diagnostic procedures and methods of collecting material do not permit definitive antemortem diagnosis. However, culturing, acid-fast bacilli staining, histopathology, PCR and immunological marker evaluation may prove useful. Unassigned: Three horses were admitted to a clinic for intensive care and a final diagnosis. Physical examination and additional tests were perfo...
Schwarz S, Kummer S, Klang A, Walter I, Nell B, Brandt S.Squamous cell carcinoma (SCC) is the most common malignant tumor disease in horses. It predominantly affects the ocular, oronasal, and anogenital region. Equine SCC is difficult to treat, also because important aspects of SCC development and metastasis are still unclear. We previously provided evidence that equine SCC cells can adopt a stem cell-like phenotype as a hallmark of malignant progression. Here, we investigated whether equine SCCs harbor endothelial-like tumor cells that form an alternative network of pseudo-vessels better known as vasculogenic mimicry (VM). Following histopathologic...
He H, Han L, Ni W, Yu J, Liu K, Li W, Li C, Hu S, Li C, Li X.Herbivores represent crucial subjects for mining highly efficient carbohydrate-active enzymes (CAZymes) from gut microbiomes. Here, we analyzed 12,763 metagenome-assembled genomes (MAGs) from the horse gut, revealing that its microbial community as a rich reservoir of CAZymes diversity, with 5,204,848 glycoside hydrolases (GHs) and 4,596,191 glycosyl transferases (GTs) identified. Our findings demonstrate that Bacteroidota (5,479,287 CAZymes) and Bacillota_A (2,987,684 CAZymes) serve as the primary functional phyla for plant polysaccharide degradation. A total of 17,250 polysaccharide utilizat...
Morales J, Ruano MJ, Tena-Tomás C, van Schalkwyk A, Loundras EA, Valero-Lorenzo M, López-Herranz A, Romito M, Batten C, Villalba R, Agüero M.African horse sickness (AHS) is a disease affecting equids caused by the AHS virus (AHSV). The World Organisation for Animal Health (WOAH) includes AHS as a notifiable disease and, upon detection within the European Union, immediate control and eradication measures are mandated. Thus, validated diagnostic methods for rapid AHSV detection are essential. The Agüero 2008 and Guthrie 2013 rRT-PCR methods have been widely validated for detection of any AHSV strain and are included as reference rRT-PCRs in the WOAH manual. However, the WOAH Reference Laboratory for AHS in the Republic of South Afri...
