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.
Hurlimann J, Darling H.The synthesis of immunoglobulins by the salivary glands from eight different species was studied. It has been demonstrated that salivary glands from the cow, horse, sheep, pig, rat and guinea-pig preferentially synthesize a fast migrating immunoglobulin which seems to be analogous to IgA. In three of the species, the cow, sheep and pig, the IgA-like component cross-reacts with human IgA. The IgA synthesized by the salivary glands from the rat cross-reacts with the mouse IgA. When one compares the salivary IgA from the cow, horse, sheep, pig and rat with the IgA synthesized by the lymph nodes,...
Urasawa S, Urasawa T, Ishizawa F, Taniguchi K.Bovine and equine sera were screened for poliovirus-reactive immunoglobulins (PRIgs) by means of neutralization and precipitation reactions with type 1 poliovirus. Bovine serum B1826 and B36 were found to contain such PRIgs from their reactivity to various PRIgs-resistant mutants of type 1 poliovirus origin. Neutralization and precipitation reactions with six mono-specific antibodies obtained by absorbing antiserum with each of the six different PRIgs-resistant virus mutants revealed that three antibodies were active in precipitation reaction while the others were substantially ineffective. On...
Araujo GH, Rocha Filho AN, Lopes EP, Moya CF, Alvarenga MA.The effects of a low dose of equine purified FSH (eFSH) on incidence of multiple ovulations and embryo recovery rate in mares were studied. During the physiological breeding season in Brazil (19 degrees 45'45'S), 14 Mangalarga Marchador donor mares were used in a crossover study and another 25 mares of the same breed, between 3 years and 12 years of age were used as recipients for the embryo transfers. Donors were monitored during two consecutive oestrus cycles, an untreated control cycle followed by a treated cycle, when eFSH was administered. In both cycles, after an embryo collection attemp...
Ito A, Imai S, Ogimoto K, Nakahara M.The composition of intestinal ciliates excreted in the feces of 20 Tokara native ponies kept in Iriki farm of Kagoshima University was surveyed. Eleven genera consisting of 18 species were identified based on the description of Strelkow. One new genus including a new species, Wolskana tokarensis n. gen., n. sp., of the family Buetschliidae was recognized and described. The average ciliate density of all horses was 13.8 x 10(3)/ml. Those of stallions (n = 5), mares (n = 11) and foals (n = 4) were 3.9, 16.1 and 43.3 x 10(3)/ml respectively. The value of stallions was significantly lower and that...
Haack D.For the inoculation of the dermatophyte-test-medium Fungassay, 200 skin scrapings from horses, 13 from cattle and 13 from artificially infected guinea pigs were used. As control methods, the alkali method, the fluorescent microscope technique and the usual mycological culture were available. For the analysis of skin scrapings, the Fungassay culture mediums are clearly inferior to the usual mycological culture. Fewer dermatophytes were isolated and false positive as well as false negative results occurred. The cultivation of Trichophyton verrucosum failed on the dermatophyte-test-medium.
Kantanen J.Domestic animal production in the arctic region is often thought to be based exclusively on reindeer herding. There are, however, regions in Northern Europe and Siberia having a long tradition in rearing breeds of cattle and horse adapted to the northers conditions also. The development of these arctic animal breeds has been largely founded on old tradition rather than on the programs of breeding organizations. As a result of the selection carried out by nature and man, the domestic animals of arctic regions express characteristics that are metabolic, structural, associated with reproductive p...
Zeilmann M.A literature review of the clinical syndrome HYPP (Hyperkalemic periodic paralysis) affecting Quarter Horses is given. HYPP is characterized by sporadic attacks of muscle tremors, weakness and/or collapse, lasting for variable periods of time. Diagnosis is based on physical findings in association with hyperkalemia. In horses with HYPP, the regulation of ion transport through the sodium channels in the muscle cells occasionally fails, causing uncontrollable muscle twitching. Further investigations into molecular genetics reveals a mutation in the gene responsible for sodium and potassium regul...
Kihurani DO, Masake RA, Nantulya VM, Mbiuki SM.Following an outbreak of trypanosomosis in horses on a farm in Kenya, 18 trypanosome isolates were collected from the infected animals over a period of one and a half years and cryopreserved for characterization. The characterization was done on the basis of morphology using Giemsa-stained blood and buffy coat smears, infectivity to mice, recombinant DNA hybridization, and chromosome separation by orthogonal field alternation gel electrophoresis (OFAGE). Morphologically, all the trypanosome isolates were identified as belonging to the subgenus Nannomonas, and a total of 16 out of the 18 isolat...
Looijen MG, New DJ, Fischer CD, Dardari R, Irwin KM, Berezowski CJ, Bond SL, Léguillette R.OBJECTIVE To evaluate the mRNA expression of T helper (Th)1, Th2, and Th17 cell-associated inflammatory mediators in cells of bronchoalveolar lavage fluid samples collected from healthy horses exposed to hyperbaric oxygen (HBO) and to monitor blood oxygen concentration during and following HBO therapy. ANIMALS 8 healthy horses. PROCEDURES In a randomized controlled crossover design study, each horse was exposed (beginning day 1) to 100% oxygen at a maximum of 3 atmospheres absolute (304 kPa) daily for 10 days or ambient air at atmospheric pressure in the HBO chamber for an equivalent amount of...
Märki U, Osterhoff DR.A method using methotrexate for horse lymphocyte cell synchronization and thymidine for incorporation into DNA replication is described. This method provides a powerful technique for the study of chromosomal abnormalities and detailed analysis of chromosomal replication patterns. The determination of horse karyotypes with many similar chromosomes needs a special method which reveals the numerous and informative stages of the cell cycle. Horse lymphocyte cell cultures treated with colcemid (20 min) and harvested 6 hours after the release of the 17 hour-block with methotrexate show the best resu...
Dusek J, Munk Z.In a set of mares of English Thoroughbred horse of the Napajedla stock the gravidity length in the time period from 1880 to 1972 was evaluated. The variability of the gravidity length was evaluated in sets which were put together by combination of two age groups with a division of the studied time period into ten-year stages. Variance and sample means of the gravidity lengths in these sub-groups are significantly different in the period under study. In order to eliminate the action of non-genetic influences qualifying the variability of the gravidity length, and to increase the objectivity of ...
Altmeyer P, Holzmann H, Stöhr L, Koch HJ.White horses are subject to age-dependent coat depigmentation. They are dark gray or black at birth and lose their coloring between their second and fourth year. Beginning at about age 10 their coat takes on a characteristic silver-gray coloring. The purpose of this paper was to find out to what extent the endogenic alpha-MSH level changes with the change in pigmentation. alpha-MSH plasma levels were determined by radioimmunologic analysis in 3 age groups of white Camarque horses: age group 1 consisted of dark horses with a mean age of 1.2 years and a mean alpha-MSH level of 106.4 pg/ml +/- 18...
Arav A, Carney JN, Pease GR, Liu KL.This research study explores the process of cryopreservation of stallion semen, focusing on improving the thawing procedures using thermal hysteresis proteins (THPs) from Antarctic and Arctic fish in order to […]
Dumasia MC, Houghton E.The research investigates the biosynthesis of a particular isomer called 5(10)-estrene-3 alpha, 17 beta-diol in stallion testes and how it affects the formation of 19-nor steroids and oestrogens. Summary of […]
Bowling AT, Williams MJ.Two additional specificities (Dq and Dr) were assigned to the D system of horse red cell alloantigens following discussion of the 1989 ISAG Horse Comparison Test (HCT) results. Family and population data support 25 phenogroups defined by the enhanced battery of 17 D system factors.
DURAN-JORDA F.This research article investigates the significance of eosinophil cells in horses and camels, focusing on the large granules found in these cells and their similarities to smaller red blood cells. […]
Hain-Saunders N, Knight DR, Bruce M, Riley TV.Recent increases in community-associated Clostridioides difficile infections have highlighted the importance of monitoring toxigenic C. difficile from animal and environmental sources. We provide the complete circularized genomes of two toxigenic C. difficile strains isolated from feral horse faeces. Genome N64 (sequence type 964) consists of a single chromosome of 4,078,791 bp, while genome H251 (sequence type 963) comprises one chromosome (4,304,722 bp) and three plasmids (150,942 bp, 11,534 bp, and 9,074 bp).
Watanabe M, Sato F, Innan H.We investigated the changes in inbreeding levels in Japanese Thoroughbred horses over the past 46 years. Our results show a significant increase in inbreeding over the past 30 years, primarily due to the influence of two sires, Northern Dancer and Sunday Silence. Northern Dancer's bloodline spread gradually through descendants like Northern Taste, leading to a slower increase in the inbreeding coefficient. In contrast, Sunday Silence was directly imported and became a leading sire, causing a rapid increase in his blood proportion and inbreeding coefficient. Our findings suggest that monitoring...
Finno CJ.In the field of equine muscle disorders, many conditions have a genetic basis. Therefore, genetic testing is an important part of the diagnostic evaluation. Validated genetic tests are currently available for 5 equine muscle disorders: hyperkalemic periodic paralysis, malignant hyperthermia, glycogen branching enzyme disease, type 1 polysaccharide storage myopathy, and myosin heavy chain myopathy. These diseases should be tested for in the appropriate breeds with clinical signs of disease or as part of breeding management. Genetic testing in veterinary medicine is not regulated, and therefore,...
Faulk C.Sequencing a genome by students has now become practical as we demonstrated with our recent publication of the Przewalski's horse (Equus ferus przewalskii) genome. In this review, I describe my experience teaching genome assembly in the classroom. In my course, students sequenced, assembled, and published a high-quality genome for Przewalski's horse using Oxford Nanopore long-read sequencing with only $4000 of materials. Along with the genome, we assembled the mitochondrial genome, sequence variants, predicted gene annotations, and DNA methylation levels. Our genome statistics far exceeded the...
Barsi B, Oláh J, Posta J.The Hungarian Coldblood horse was developed in the 1920s by crossing local mares with draft horses imported from Belgium and France, and was approved as an official horse breed in 1954. The aim of the study was to analyze the quality of the pedigree, generation interval, gene origin, and inbreeding. The pedigree information was received from the Hungarian Coldblood Horse Breeding Association. The studbook data of the registered animals up to 2023 were evaluated. Two reference populations were chosen: horses having offspring in 1989 and 2023. The final database contained 21,699 horses. Pedigree...
Bugno M, Jabłońska Z, Słota E.The aim of the study was to optimize hybridization conditions of molecular probes specific for X sex chromosomes of the domestic horse in mare oocyte chromosomes. Mare oocytes, recovered from slaughterhouse ovaries by scraping the granulosa layer, were cultured in vitro. Metaphase II mature oocytes were treated with hypotonic solution and fixed, followed by hybridization of the molecular probe specific for the X chromosome ofthe domestic horse. Hybridization of probes specific for mouse heterosomes on mouse oocytes and early embryos was performed to verify the FISH technique. Of 438 oocytes an...
Rocha IAB, Araujo F, Rosa LP.Friesian horses are recognized for severe genetic restriction due to intensive selection. Still, the genetic diversity, founder representation, and prevalence of inherited disorders in the Brazilian Friesian population, which is comprised of fewer than 500 individuals, have not been previously investigated AIMS/OBJECTIVES: characterize the genetic diversity, inbreeding, founder representation using pedigree-based tools, and frequency of known pathogenic, behavioral, and white spotting alleles in Friesian horses registered in Brazil METHODS: Pedigree data from 411 Friesian horses (2003-2024) we...
Padilha FGF, El-Jaick KB, de Castro L, Dos Santos Moreira A, de Almeida FQ, Ferreira AMR.The aim of this study was to look for mutations in the equine gene and to identify sequence variants that might be associated with the phenotype and performance of Brazilian sport horses training for events in a tropical climate. Among 17 such horses direct DNA sequencing and mutation analysis of the exon 15 and the intron-exon boundaries of revealed 2 new sequence variants in the intron 14-15, designated c.1681-86G > A and c.1681-129delA. Wild-type/deletion heterozygotes (A/del) had a lower mean subcutaneous fat layer in the region of the gluteus medius, as measured by ultrasonography, tha...
Ząbek T, Witarski W, Semik-Gurgul E, Szmatoła T, Kowalska K, Samiec M.Ex vivo expansion of chondrocytes in monolayer (ML) culture for therapeutic purposes is burdened with difficulties related to the loss of cartilaginous phenotype. Epigenetic mechanisms responsible for regulation of gene expression are believed to underlie chondrocyte dedifferentiation. We have inspected the relevance of DNA methylation alterations for passage-related differential expression of NFATC1 gene involved in hard connective tissue turnover and development, NADSYN1 influencing redox metabolism, and JAK3 - an important driver of inflammation. We have assessed relative amount of transcri...
Simpson KS, Adams MH, Behrendt-Adam CY, Baker CB, McDowell KJ.Complex changes in gene expression must occur at the proper time and in the appropriate tissues for pregnancy to be successful. Therefore, research aimed at defining the regulation of gene expression in conceptuses is of critical importance. However, information on developmentally regulated changes in gene expression in horse conceptuses is sparse and inadequate. In the present study, suppression subtractive hybridization was used to identify genes that are expressed more highly at day 15 than on day 12 of gestation. This period encompasses maternal recognition of pregnancy and the beginning o...
Morrell JM, Johannisson A.The effect on sperm motility and chromatin integrity of adding homologous or heterologous equine seminal plasma (SP) to fresh stallion spermatozoa selected by single layer centrifugation (SLC) was studied. No statistical difference in mean progressive motility was seen after adding SP at time 0 h, although there were differences for individual stallions. The proportion of spermatozoa with high velocity was increased compared to untreated SLC-selected spermatozoa (P < 0.05), with significant differences between individuals (P < 0.01). When the SLC samples were stored for 24 h before a...
