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.
Stewart F, Allen WR.Gonadotrophin-receptor binding studies involving the use of 125I-labelled highly purified FSH and LH have shown that equine gonadal tissues possess similar numbers of specific FSH and LH receptors per cell as the gonadal tissues of other mammals. However, while rat, cow and pig gonadal tissues were shown to bind as much 125I-labelled PMSG as 125I-labelled LH on a molar basis, the equivalent equine tissues bound only less than or equal to 4% as much of the labelled PMSG as LH. Competitive binding studies involving the use of radioreceptor assay techniques have further demonstrated that the smal...
Strauss SS, Chen CL, Kalra SP, Sharp DC.Fifteen Pony mares, ovariectomized during the previous summer, were randomly assigned to three seasonal treatment groups, winter, spring and summer (N = 5). At the designated season, the animals were killed and hypothalamic areas were collected and assayed by radioimmunoassay for gonadotrophin-releasing hormone (GnRH) activity. The hypothalamic areas were sectioned into 54 5-mm cubes to determine the sites of GnRH storage. Maximum immunoreactive GnRH activity was located in an oblique pattern extending from the arcuate nucleus-median eminence area to the anterior hypothalamic area dorsally and...
Merchant-Larios H.The establishment and sexual differentiation of the gonads of horse embryos were studied using high-resolution techniques. The most dramatic observation is the early cytodifferentiation of the somatic cells into steroidogenic cells which takes place before sexual differentiation of the gonads. A unique morphogenetic pattern is established during this process: the seminiferous cords of the testis are completely segregated from the steroidogenic tissue by a basal lamina, while in the medulla of the ovary, steroidogenic cells differentiate inside the epithelial cords which contain germ cells. Thi...
Lancaster WD, Theilen GH, Olson C.DNAs from bovine papilloma virus(BPV)-induced hamster tumors and from equine connective tissue tumors of unknown etiology were examined for BPV DNA sequences by molecular hybridization. DNA from two distinct classes of BPV (type 1 and type 2) was labeled in vitro and used as probes. Analysis of DNA-DNA reassociation kinetics indicated that both virus types were capable of tumor induction in the hamster. DNA isolated from 6 of 7 equine tumors accelerated the reassociation of the BPV DNA probes. BPV type 1 or type 2 DNA hybridized extensively to DNA from 3 tumors, while 3 other tumors contained ...
McManus DP, Smyth JD.Extracts of the horse and sheep strains of Echinococcus granulosus and E. multilocularis were compared on the basis of their isoenzyme patterns for 10 enzymes by means of isoelectric focusing in polyacrylamide gels. The enzymes examined were: acid phosphatase, lactate dehydrogenase, malate dehydrogenase, malic enzyme, phosphoglucoseisomerase, isocitrate dehydrogenase, adenylate kinase, aldolase and alpha-glycerophosphate dehydrogenase. Interspecific and intraspecific differences are apparent in the isoenzyme profiles of all the enzymes except adenylate kinase; the pattern and activity of adeny...
Karasek M, Marek K, Kunert-Radek J.The influence of gonadotropic hormones on the ultrastructure of rat pinealocytesin short-term organ culture was studied. Human chorionic gonadotropin (HCG), as well as pregnant mare serum gonadotropin (PMSG), caused a marked activation of pinealocytes. An hypothesis is discussed implying the presence of a feedback mechanism between the pineal organ and the hypothalamo-hypophysial system.
Hendrikse J, van der Holst W, Best AP.Examination of 539 ejaculates of stallions of various breeds showed that approximately 60 per cent of the spermatozoa were completely normal morphologically. Of these morphologically normal spermatozoa, 13 per cent were dead. The total proportion of live spermatozoa was 75 per cent, 32 per cent being obviously abnormal (22 per cent of live and 10 per cent of dead spermatozoa). Separated heads (normal as well as abnormal) were significantly more common among dead spermatozoa. Protoplasmic droplets (both at the neck and at the end of the middle piece) were mainly present in live spermatozoa. As ...
Kisailus EC, Kabat EA.The specificity of Bandeiraea simplicifolia lectin I (BS I) has been studied by competitive-binding assays (CBA) using tritium-labeled human B and hog A substances. Blood-group B substances isolated from horse gastric mucosae and from human ovarian-cyst fluids were much better inhibitors of binding of tritiated blood-group B substance to insoluble BS I-Sepharose 2B than were human blood-group A substances from saliva and ovarian-cyst fluid. A and B active blood-group substances showed the same range of potency in inhibiting binding of tritium-labeled hog A substance to BS I-Sepharose 2B. CBA w...
Looze Y, Polastro E, Deconinck M, Leonis J.Spectrophotometric studies of the alkaline isomerization of horse heart and yeast cytochrome c show that the haemoproteins from Saccharomyces cerevisiae differ significantly from the mammalian cytochrome c. Apparent pKa values of 8.41, 8.40 and 8.73 for isol-1-(the methylated and unmethylated forms) and iso-2-cytochrome c respectively, from baker's yeast were determined and compared with the value of 9.40 found for horse heart cytochrome c. The transitions, measured by observing the decrease of the absorbance at 695 nm as the pH increases, have been found to strictly parallel the decrease in a...
Mirck MH.In 3,791 horses and ponies submitted to the Department of Internal Disease of Farm Animals of the Faculty of Veterinary Medicine, Utrecht, the faeces were studied for the presence of parasites. The results were classified by age groups and months of arrival. Eggs of the Strongylus type were found to be present in 57.3 per cent of the faecal samples, eggs of Parascaris equorum were present in 6.1 per cent, eggs of Oxyuris equi in 1.2 per cent, eggs or larvae of Dictyocaulus arnfieldi in 0.2 per cent, eggs of Anoplocephala in 2.5 per cent and oocysts of Eimeria leuckarti in 0.3 per cent. Eggs of...
Barthold SW, Olson C.Cultured cells from bovine papilloma virus (BPV)-induced fibroblastic tumors and normal dermis of cattle, horses, and hamsters were examined for cell membrane or internal neoantigens, using the indirect immunofluorescence technique. Sera from cattle and horses bearing BPV-induced fibromas cross reacted with cell membranes of tumor, but not with normal dermal cells of both species. The reaction could be blocked with homologous, but not heterologous, serum of these 2 species. Immunofluorescence was not detected with sera from hamsters bearing BPV-induced sarcomas if incubated with bovine, equine...
Studdert MJ.Set in a context of immunodeficiency diseases in general this paper provides a brief, illustrated review of a primary, severe, combined immunodeficiency (PSCID) disease of Arabian foals. Affected foals are clinically normal at birth but beginning at about 10 days of age they develop a range of clinical signs particularly bronchopneumonia and diarrhoea with which adenoviruses are peculiarly associated. Despite intensive therapy foals invariably die by about 3 months of age. Affected foals are profoundly lymphopagenic (greater than 1000 lymphcoytes per mm3). There is thymic and lymph node hypopl...
Fujiki Y, Rathnam P, Saxena BB.A tentative amino acid sequence of the beta-subunit of equine follicle-stimulating hormone (FSH) was derived from the sequences of tryptic, thermolytic as well as peptic, subtilisin, and chymotryptic peptides. Equine FSH-beta is analogous to human FSH-beta except six amino acid substitutions at positions 12, 16, 21, 62, 108, and 114. The amino acid sequence suggests that the hormone-specific beta-subunits of FSH are similar at the interspecies level, whereas the amino acid sequences of the hormone nonspecific alpha-subunits show variations.
Rathnam P, Fujiki Y, Landefeld TD, Saxena BB.Six hundred milligrams of follicle-stimulating hormone (FSH), containing 110 NIH-FSH-S1 units/mg, was isolated from 9 kg of equine pituitary glands. The equine FSH was dissociated into alpha- and beta-subunits. A tentative amino acid sequence of the alpha-subunit was determined. The alpha-subunit contained 82 amino acids. The equine FSH-alpha is shorter by 10 to 14 amino acids at the NH2 terminus and has several substitutions at several positions as compared with human FSH-alpha and bovine thyroid-stimulating hormone-alpha. At the intraspecies level, the alpha-subunits of human FSH, human lute...
Witzel DA, Smith EL, Wilson RD, Aguirre GD.Electroretinographic studies of myctalopic Appaloosa horses demonstrated photopic and scotopic abnormalities similar to those in humans with congenital stationary night blindness (CSNB) of the Schubert-Bornschein type. The phototopic abnormalities consisted of reduced b-wave amplitudes and slower than normal b-wave implict time. The dark-adapted ERG's consisted of a simple negative potential; the scotopic b-wave was nonrecordable. However, a normal c-wave was present in the dark-adapted response. Histologic studies demonstrated no structural abnormalities that could explain the functional defe...
Finno CJ.Hoof wall separation disease (HWSD) is a genetic defect in Connemara ponies characterised by separation and cracking of the dorsal hoof wall. The disease can result in chronic inflammation, severe lameness and laminitis. Affected ponies typically show clinical signs within the first six months of life. The disease is inherited as an autosomal recessive trait. The genetic mutation is a frameshift mutation in the gene SERPINB11, (c.504_505insC). Carriers are completely normal, only ponies that are homozygous for the mutation will have clinical signs of the disease. Within the Connemara breed, ca...
von Zallinger C, Tempel K.A review of the latest literature concerning the present level of radiation therapy in veterinary medicine is given. In a general section physico-technical as well as biological fundamentals are discussed. In the special part of the paper indications for a radiation therapy of dogs, cats and horses are stated. In this respect the basis for a decision is the TNM-classification into different clinical stages according to the directions of the WHO. Tumors of the hemolymphatic system are very responsive to radiation therapy. While epithelial tumors are sensitive, tumors arising from the mesenchyma...
Yamashita J, Oki H, Hasegawa T, Honda T, Nomura T.Genetic contributions of nine historically important ancestors and allelic diversity in the Japanese Thoroughbred population were examined by applying the gene dropping simulation to the foals produced from 1978 to 2005. Full pedigree records traced to ancestors (base animals) born around 1890 were used for the simulation. Alleles originated from some of the historically important ancestors were found to be at risk of future extinction, although their genetic contributions to the foal population have increased during the last three decades. The proportion of surviving alleles to the total alle...
Rakic R, Bourdon B, Demoor M, Maddens S, Saulnier N, Galéra P.An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Carvalho AL, Dias JM, Sanz L, Romero A, Calvete JJ, Romão MJ.The purification, crystallization and identification by X-ray diffraction analysis of a horse kallikrein is reported. The protein was purified from horse seminal plasma. Crystals belong to space group C2 and the structure was solved by the MIRAS method, with two heavy-atom derivatives of mercury and platinum. X-ray diffraction data to 1.42 A resolution were collected at the ESRF synchrotron-radiation source.
McKinnon AO, Brown RW, Pashen RL, Greenwood PE, Vasey JR.THE name inhibin was first used around 60 years ago for a water-soluble. non-steroidal, gonadal factor that would regulate follicle-stimulating hormone (FSH) secretion through negative feedback McUullagh 1930. Inhihin is now defined as a glycoprotein hormone, consisting of two dissimilar, disulphide-linked, subunits termed at and 13 1 Burger and Igarashi 1988). Effective methods for blocking inhibin production could provide useful means by which FSH secretion, and therefore ovarian function and fertility, could be improved in the female. Increased ovulation rates have been demonstrated in shee...
Henner J, Poncet PA, Aebi L, Hagger C, Stranzinger G, Rieder S.Coat color played an important role during domestication and formation of breeds. Livestock breeders often had special preferences for particular color phenotypes because they believed them to be associated with performance or fitness traits. Socio-cultural reasons might have had an influence on color selection as well. Recently genetic tests on DNA level got available to genotype in any individual horse for basic horse coat colors (chestnut, bay, black). In particular, hidden carriers of the recessive chestnut and black allele are recognizable with these tests. A sample of 162 Franches-Montag...
Ledwozyw A, Jabłonka S, Tusińska E, Herbut M.Factor VIII level in horse, cattle, sheep and pig plasma was estimated by the use of synthetic chromogenic substrate S-2222 (benzoyl-isoleucyl-glutamyl-glycyl-arginyl-p-nitronilide). The highest level of this factor was stated in pig, the lowest one in sheep plasma.
Garza F, Thompson DL, Mitchell PS, Wiest JJ.Five lighthorse mares were actively immunized against gonadotropin releasing hormone (GnRH) conjugated to bovine serum albumin (BSA) to study the involvement of GnRH in luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion following ovariectomy (OVX) and after administration of testosterone propionate (TP). Five mares immunized against BSA served as controls. Immunizations were started on November 1, and OVX was performed in June (d 1). All mares were treated with TP from d 50 to 59 after OVX. On the day of OVX, concentrations of LH were lower (P less than .05) in GnRH-immu...