Genetics in horses encompasses the study of hereditary traits and the genetic makeup that influences various characteristics and health conditions in equine populations. This field involves the analysis of genes and their functions, inheritance patterns, and the impact of genetic variations on traits such as coat color, performance ability, and susceptibility to diseases. Research in equine genetics employs techniques such as genome mapping, sequencing, and genetic testing to identify specific genes and mutations associated with these traits. This page gathers peer-reviewed research studies and scholarly articles that explore the genetic basis of equine traits, the methodologies used in genetic research, and the implications for breeding, health management, and conservation of horse breeds.
Gospodarowicz D.A highly purified preparation of PMSG has been obtained from fresh serum and from a commercial preparation. Carbohydrate and amino acid compositions have been determined. The carbohydrate content of PMSG is 46.7% and the molecule is rich in Sialic Acid (13.5%). The apparent molecular weight of PMSG has been determined by SDS polyacrylamide gel electrophoresis. A molecular weight of 53,000 has been found for the unreduced and unalkylated molecule. After reduction and alkylation, the molecular weight fell to 23,000. From these values it has been concluded that PMSG is an oligomeric molecule comp...
Blohina NV, Khrabrova LA.Russia has a significant pedigree diversity of horse breeds with unique gene pools that are well adapted to a wide variety of harsh natural and climatic conditions, are characterized by universal performance and high productive qualities, and are of significant interest to the world horse breeding. Genetic studies of population diversity in horse breeding are very relevant, since many domestic horse breeds are under threat of extinction. Biomaterials (hair, blood, semen) from horses of 15 local breeds bred in the Russian Federation and neighboring countries (CIS) were selected for the research...
Díaz S, Dulout FN, Peral-García P.Genetic polymorphism was analyzed for five blood proteins: albumin - Al, esterase - Es, alpha(1)B-glycoprotein - Xk, transferrin - Tf and hemoglobin - Hb in 200 Thoroughbred (TB) and 124 Argentine Creole (AC) horses. Of the five systems examined, Tf and Hb were not in Hardy-Weinberg equilibrium in either breed and Es was not in equilibrium in the Creole breed. Genetic variability, estimated as average heterozygosity, was higher in AC (H = 0.585 +/- 0.131) than in TB (H = 0.353 +/- 0.065). The genetic differentiation between these two populations (F(ST)) was 0.109. Thus, of the total genetic di...
van der Mey GJ.Horse-breeding in the Netherlands is briefly reviewed. Particular attention is paid to the number of foals of various breeds. Some effects of inbreeding in Friesian horses are discussed. As regards methods selection, attention is mainly paid to saddle horses. The role of veterinarians (from the point of view of selection for soundness) is described. Selection is based on the results of studies in the Faculty of Veterinary Medicine in Utrecht. A number of these results are reviewed.
Junkkari R, Mykkänen A, Sulku P, Rantala M, Pohjanvirta T, Eklund M, Pelkonen S, Grönthal T. subsp. (), an opportunistic pathogen often found in the stable environment and upper respiratory tract of young horses, can cause severe pneumonias in Equidae. In this study we investigated the occurrence, genetic variation and antimicrobial susceptibility of isolates from 63 weanling horses kept in loose housing or conventional stables. The bacterial isolates were typed by using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The possible associating factors (stable type, age, breed and clinical signs) for positive finding were analysed using logistic regre...
Cox JE.Testes were collected from normal and cryptorchid horses of a variety of breeds and ages and weighed after dissection from the epididymis. Scrotal testes grow little until the second winter of life and little thereafter, although a nearly mature body weight is reached by the end of the first winter. Scrotal testes in unilateral cryptorchids tend to be larger than those of normal stallions, sometimes exceedingly so, although occasional small scrotal testes are recorded. Inguinal testes show some tendency to grow during the second winter but the data are difficult to analyse beyond that age beca...
Li Y, Fu C, Yun X, Zhang H, Yang T, Feng M, Wang X, Qian S, Xing W, Yang R, Wu J, Liu Y, Zhao C.With growing demand for pedigree verification and breed management in horses (Equus caballus), reliable paternal lineage tools are essential. Y-chromosomal STRs (Y-STRs) have advantages over autosomal STRs due to paternal inheritance and lack of recombination. However, few validated loci and no standardised efficient genotyping systems limit their use. Current methods often require multiple reactions, increasing cost and labour. Thus, identifying informative Y-STR loci and developing a multiplex PCR system for cost-effective paternal lineage analysis is urgently needed. Objective: To identify ...
Trauner AM, McCoski SR, Satterfield MC, Bradbery AN.Reproductive health of male offspring following perturbations in maternal nutrition is not well-described in the horse; therefore, the objective of this study was to determine the effects of maternal overnutrition on neonatal foal testicular development. Sixteen Quarter Horse mares were used in a completely randomized design and stratified by expected foaling date, body weight, and body condition score into 1 of 2 dietary treatments beginning on gestational day 235: control (CON; n = 8) fed to meet nutrient requirements and overfed (HIGH; n = 8) fed 40% above CON. At 5 h postpartum, f...
Ablondi M, Eriksson S, Gelinder Viklund Å, Mikko S.The aim of this study was to better understand the genomic architecture behind performance-related traits in sport horses. In this study, we conducted a haplotype-based genome-wide association study (GWAS) for 36 conformation and free jumping phenotypes recorded during routinely conducted young horse evaluation tests involving 380 Swedish Warmblood (SWB) horses. The horses were evaluated by expert judges using both traditional and linear evaluation systems. All samples were genotyped using the 670K Affymetrix® Axiom® Equine Genotyping Array, haplotypes were first phased, and haplotype blocks...
Gysens L, Depuydt E, Patruno M, Haspeslagh M, Spaas JH, Martens A.Sarcoids are the most common equine skin tumours Although they do not metastasize, they can be locally aggressive and cause significant clinical symptoms in affected horses. Despite being common, very little is known about the host immune response and the biological mechanisms underlying persistence and recurrence of equine sarcoids. The latter reflects the need for further research in this field. This in-vitro study used sarcoid explants from horses with naturally occurring sarcoids (n = 12) to evaluate the induction of a humoral immune response directed against equine sarcoid-derived bovin...
Poppie MJ, McGuire TC.Foals with combined immunodeficiency (CID), a fatal genetic defect in the production of both B and T lymphocytes, are born without immunoglobulins and are unable to synthesise them. CID foals receiving immunoglobulins via the dam's colostrum may live up to four months of age. Those CID foals with failure of passive transfer (FPT) die at a much earlier age. The occurrence of CID is of value in studying passive transfer of immunoglobulins, as no confusion exists as to when passive transfer ends and active synthesis of immunoglobulins begins. A high correlation has been found between early foal d...
Magnuson NS, Decker DM, Perryman LE.1. Activities of S-adenosylhomocysteine (AdoHcy) hydrolase were measured in tissues of horses with severe combined immunodeficiency. No decrease in activity of the enzyme was detected.
2. The activity in erythrocytes was 14.2 ± 9.2 nmol AdoHcy formed/min/g hemoglobin and in fibroblasts it was 28.0 ± 7.9 nmol AdoHcy formed/min/108 cells.
3. Km values were obtained for hemolysates (0.77 μM) and for fibroblast lysates (0.59 μM).
4. Effects of 2′-deoxyadenosine on enzyme inactivation were studied.
Cabañes FJ, Abarca L, Bragulat MR, Calvo MA.The ability of 17 strains of Epidermophyton to perforate hair in vitro using the Ajello & Georg's test procedure and a modification of Lu's method has been studied. Following the Ajello & Georg's test procedure only E. stockdaleae perforated hair. Sporadically some strains of E. floccosum perforated horse hair. We noted as well unusual perforations originated from inside to outside of the hair. By the other technique, all strains, excepting E. floccosum var. nigricans in child hair, perforated hair. E. floccosum showed these perforations later than E. stockdaleae.
Valentine BA, Hedstrom OR, Miller WH, Scott DW, Mathies S.A blue roan Percheron foal was born with poorly circumscribed patchy alopecia of the trunk and legs. Teeth and hoof development were normal. Alopecia was progressive, becoming almost complete by 1 year of age. Histopathological findings in a skin biopsy obtained at 7 months of age were consistent with severe follicular hypoplasia. Sebaceous glands, epitrichial sweat glands and arrector pilae muscles were normal. The horse is alive and otherwise well at 6 years of age, although adult stature is considered small for this breed. The clinical history and histopathological findings are most consist...
Fatemi-Nainie S, Anderson LW, Cheevers WP.MC-1 is an equine sarcoid-derived cell line which spontaneously releases a retrovirus possessing genomic sequence homology with an inducible endogenous retrovirus of normal equine cells. A complete characterization of MC-1 tumor cells was undertaken, including morphology, growth kinetics, and saturation density, selective growth in semisolid media, uptake of 2-deoxyglucose, and tumorigenicity in athymic nude mice. MC-1 cells, in contrast to normal equine dermal fibroblasts, exhibit all of the characteristics of malignantly transformed cells.
Kakoi H, Gawahara H, Miura N.An unusual D system phenogroup appeared in one family line of Anglo-Arab horse. This phenogroup probably originated from inheritance with an apparent absence of factors and was transmitted through successive generations.
Loch WE, Swantner LD, Anderson RR.Mean weight of 20 Quarter Horse placentas on a wet basis was 3.27 +/- 0.17 kg. These placentas contained mean dry fat-free tissue, DNA, RNA and collagen weights of 411 +/- 24 g, 11.2 +/- 0.6 g, 12.4 +/- 0.7 g and 210 +/- 15 g, respectively. In Ponies and Quarter Horses, there was a trend towards a decrease in these 4 values as gestation length increased. Analysis of placentas of Ponies fed different amounts of endophyte fungus-infected fescue seed showed that weight of dry fat-free tissue increased with increasing percentages of fescue seed in the diet. Diets containing fescue seed resulted in...
McClure JJ, Koch C, Powell M, McClure JR.Associations were sought between ELA A1-A10 and W11 antigens and the presence of laryngeal hemiplegia, arytenoid chondritis, umbilical hernias and cryptorchidism in Thoroughbreds and/or Quarter Horses. No significant associations were detected between laryngeal hemiplegia and any ELA antigen in Thoroughbreds. The association between arytenoid chondritis and A9 was significant with a relative risk (RR) of 15.6 and aetiologic fraction (EF) of 0.80 in Thoroughbreds. There were apparent associations based on RR between A4 and A5 in Quarter Horses with umbilical hernias (RR = 7.5 and 6.1 respective...
Malek G, Richard H, Beauchamp G, Laverty S.Focal bone microcracks with osteoclast recruitment and bone lysis, may reduce fracture resistance in racehorses. As current imaging does not detect all horses at risk for fracture, the discovery of novel serum biomarkers of bone resorption or osteoclast activity could potentially address this unmet clinical need. The biology of equine osteoclasts on their natural substrate, equine bone, has never been studied in vitro and may permit identification of specific biomarkers of their activity. Objective: (1) Establish osteoclast cultures on equine bone, (2) Measure biomarkers (tartrate resistant ac...
Kay PH, Dawkins RL, Bowling AT, Bernoco D.Plasma or serum samples from 12 Arabian and 181 standardbred horses have been typed using an immunofixation technique to determine electrophoretic polymorphism of equine third complement component (C3). Six distinctly different electrophoretic patterns of equine C3 have been recognized thus far. SDS PAGE analysis of equine C3/anti C3 complexes revealed that the submolecular structure comprised an alpha chain and beta chain of molecular weights approximately 118,000 and 63,000 daltons respectively. The molecular weights of the alpha and beta chains were similar in all electrophoretic variants t...
da Silva AC, Brass KE, da Silva Loreto E, Vinocur ME, Pozzobon R, da Silva Azevedo M.The aim was to detect the presence of polymorphisms at exons 1, 2, 3 and 4 of the Spi2 gene, and evaluate a possible association between them and recurrent airway obstruction (RAO) or inflammatory airway disease (IAD) in thoroughbred horses, through single-strand conformational-polymorphism (SSCP) screening. Although polymorphism was not detected in exons 1, 2 and 3, three alleles and six genotypes were identified in exon 4. The frequencies of allele A (0.6388) and genotype AA (0.3888) were higher in horses affected by RAO, although no association was found between polymorphism and horses with...
Harasawa R, Higashi T.Viral DNA obtained from the equine adenovirus propagated in equine transitional cell carcinoma (ETCC) cells and in equine fetal dermis cells were compared by cleaving with isoschizomeric restriction enzymes, HpaII and MspI, and then electrophoresed in 1.4 per cent agarose gels. Differences between the HpaII and MspI cleavage patterns were evident in viral DNA obtained only from the equine adenovirus propagated in ETCC cells, suggesting site specific methylation at CpG sequences.
