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.
Baumann RP, Staczek J, O'Callaghan DJ.Equine herpesvirus type one (EHV-1) defective interfering (DI) particle DNA fragments were inserted into the XbaI site of the plasmid vector pACYC184. Five DI XbaI fragments, which ranged in molecular weight from 4.5 to 6.7 MDa, were selected for detailed analysis. Each DI DNA clone was labeled with 32P-deoxynucleotides by nick translation and hybridized to genomic digests of EHV-1 standard (STD) DNA bound to nitrocellulose. All five clones were shown to hybridize to DNA sequences derived from the left terminus (0.0-0.04 map units) of the long (L) region and from the short (S) region inverted ...
Poerio E, Parr GR, Taniuchi H.The previous studies (Juillerat, M. A., and Taniuchi, H. (1986) J. Biol. Chem. 261, 2697-2711), using a three-fragment complex (1-25)H X (28-38) X (39-104) of horse cytochrome c, have shown that invariant leucine 32 and partially invariant leucine 35, both buried in the interior, exhibit a striking difference in perturbation of binding fragment (28-38) by substitution with isoleucine. Then the idea has been proposed that the energy states of leucine 32, the Met-80-S-heme-Fe bond and other distant residues such as tryptophan 59 would be coupled to generate extra force while leucine 35 would be ...
Lazary S, Dubath ML, Luder C, Gerber H.A case of recombination between the putative class I ELA antigen series and the structure(s) governing mixed lymphocyte reactivity in an informative horse family is described. The results of serological typing, 'lysostripping' and mixed lymphocyte culture tests strongly suggest that the recombination took place between two loci and is not intragenic. An alloantigenic membrane structure, provisionally called B1, which does not belong to the known ELA series, was also involved in the cross-over. The B1 antigen resembles the class II gene products of other species in two respects: it is not prese...
Patterson SD, Bell K.Three cases of abnormal expression of the equine protease inhibitory alleles, Pi F, L, and S1, were observed following the examination of 30,000 plasma samples by one-dimensional acid (pH 4.6) polyacrylamide gel electrophoresis. Characterization of the abnormal proteins in terms of isoelectric point, molecular mass, inhibitory spectra, and sialic acid content was performed using one- and two-dimensional electrophoretic techniques. The Pi F and S1 abnormalities were postulated to be the result of amino acid substitutions causing alterations in the processing of the carbohydrate side chains. No ...
Jones LS, Berndtson WE.Testes from 47 stallions, 1-20 yr of age, were used to examine the influence of age on Sertoli and germ cell populations as well as on functional activity of Sertoli cells. For these stallions, the number of Sertoli cells per paired testes declined linearly with age, and was only 41.7% as great at age 20 as at age 2. However, development of reproductive organs proceeded until age 12-13, as evident from increases in paired testes weight and quantitative rates of spermatozoal production. Although the absolute number of Sertoli cells declined during this period of development, individual Sertoli ...
van Berlo MF, Rottier PJ, Horzinek MC, van der Zeijst BA.Equine arteritis virus (EAV) is a nonarthropod-borne togavirus. Six virus-specific RNA species have been found in EAV-infected cells having the following molecular weights: 4.3 X 10(6) (RNA1), 1.3 X 10(6) (RNA2), 0.9 X 10(6) (RNA3), 0.7 X 10(6) (RNA4), 0.3 X 10(6) (RNA5), and 0.2 X 10(6) (RNA6). RNA1 comigrates with the viral genome (M. F. Van Berlo, M. C. Horzinek, and B. A. M. Van der Zeijst, 1982, Virology 118, 345-352). All RNAs hybridized with a radio-labeled cDNA probe representing RNA6, indicating that they contain common sequences. To study this homology in more detail, RNase T1 oligon...
Kinney RM, Johnson BJ, Brown VL, Trent DW.A cDNA clone containing all of the 26 S mRNA coding region of the RNA genome of Venezuelan equine encephalitis (VEE) virus, virulent strain Trinidad donkey (TRD), has been constructed and sequenced. The nucleotide and deduced amino acid sequences of the 26 S RNA of VEE virus conform to the general organization of the alphavirus subgenomic mRNA. Excluding the poly(A) tail, the VEE 26 S RNA is 3913 nucleotides long with a protein coding region of 3762 nucleotides. Codon usage in the translated region is nonrandom and correlates well with that reported for Sindbis (SIN), Semliki Forest (SF), and ...
Weiss M, Horzinek MC.In equine dermis cells infected with Berne virus particles were first detected 10 h after infection. Virions were encountered in all parts of the Golgi system and, infrequently, in the rough endoplasmic reticulum. A unique form of budding of preassembled rigid tubular nucleocapsids was demonstrated. Masses of tubular nucleocapsids of a lesser diameter and electron density were prominent in the cytoplasm and the nucleus of infected cells. Within the Golgi system and cytoplasmic cisternae virions appeared as straight or slightly curved rods. Extremely long, aberrant virions (250 nm) were occasio...
Alexander SL, Irvine CH.Luteinizing hormone release induced by a range of small (3.3-33 micrograms) and large (300-500 micrograms) i.v. doses of gonadotrophin-releasing hormone (GnRH) was measured in acyclic (n = 4), luteal phase (n = 3) and follicular phase (n = 5) mares and compared with endogenously generated LH pulses in the same reproductive states. Extrapolation from log-linear dose-response curves showed that an LH pulse comparable to an endogenous one would be simulated by i.v. injection of 7.0 (n = 4) and 4.1 (n = 6) micrograms GnRH in luteal and follicular phase mares respectively; a much smaller dose than ...
Weers JG, Maki AH.Triplet-singlet energy transfer has been studied in the complex formed between auramine O (AO) and horse liver alcohol dehydrogenase with optically detected magnetic resonance (ODMR) spectroscopy. The results show that Trp-15 and Tyr residues transfer triplet energy mainly by a trivial process, whereas Trp-314 transfers triplet energy by a Förster process with two observed lifetimes at 77 K of 170 and 50 ms. The different Förster energy-transfer lifetimes are ascribed either to quenching of the two Trp-314 residues of the dimer by a single asymmetrically bound AO or to two distinct conformat...
Watson AG, Mayhew IG.Familial occipitalization of the atlas with atlantalization of the axis was defined as a single congenital disease in Arabian horses following a clinical, radiologic, and morphologic study of 16 horses with congenital malformations of the occiput, atlas, and axis, and from a study of three reported cases. The constant morphologic features were interpreted as congenital atlantooccipital fusion, hypoplasia of the atlas and dens, malformation of the axis, and modification of the atlantoaxial joint. Atlantoaxial subluxation was also a frequent finding. The clinical syndromes shown by these horses ...
Ishiyama T, Shinagawa M, Sato G, Fujinaga K, Padmanabhan R.Equine adenovirus (EAd) DNA prepared from infected bovine kidney (MDBK) cells contained additional sequences of about 100 to 700 bp at the left-hand end of the genome. These aberrant viral genomes were produced even after the first passage of the wild type EAd in MDBK cells and their relative amounts did not change significantly during serial passage. The left terminal fragments of two defective viral DNAs were cloned into the plasmid vector pBR322 and the nucleotide sequences of their terminal regions were analyzed. The data indicate that one viral DNA contained a duplication of the inverted ...
Matteri RL, Papkoff H, Ng DA, Swedlow JR, Chang YS.Three isoforms of equine luteinizing hormone (eLH-A, eLH-B and eLH-C) have been isolated from horse pituitary glands. Separation was achieved on the basis of charge heterogeneity by ion-exchange chromatography. These charge differences were apparent after final purification, as determined by electrophoretic mobility on polyacrylamide disc gels (RF = 0.14, 0.19 and 0.26 for eLH-A, -B and -C, respectively). Apparent size differences were also noted between the isohormones by gel filtration on Sephadex G-100. Ve/Vo ratios for eLH-A, -B and -C were 1.72, 1.54 and 1.47, respectively. All 3 isoforms...
Bousfield GR, Ward DN.After dissociating equine gonadotropins as a function of time at pH 3, we examined them by radioligand assay and sodium dodecyl sulfate polyacrylamide gel electrophoresis under nondissociating conditions (low, 0.1% SDS). Equine follicle-stimulating hormone (FSH) rapidly lost its receptor-binding activity, and low SDS-polyacrylamide gels demonstrated dissociation into subunits. Maximum dissociation occurred after 20-30 min of pH 3 incubation. Equine luteinizing hormone (LH), however, retained most biologic activity and was largely intact after 72 h of pH 3 incubation. Dose-response curves of ac...
Wand AJ, Englander SW.The 1H resonances of 11 sequential amino acids in the N-terminal helix of horse ferrocytochrome c were studied by two-dimensional nuclear magnetic resonance techniques. All the main-chain protons from Lys-5 through Ala-15 and many of the side-chain protons were assigned. J-Correlated spectroscopy (COSY) was used to distinguish protons on neighboring bonds and to recognize amino acid types. Nuclear Overhauser effect spectroscopy (NOESY) was used to define spatially contiguous protons and to determine amino acid sequence neighbors. The relayed coherence experiment (relay COSY) was used to resolv...
Ruoff WW, Baker DC, Morgan SJ, Abbitt B.DIABETES mellitus is an uncommon disease in the horse and,
when reported, is frequently secondary to Cushing’s disease
(King, Kavanaugh and Bentinck-Smith 1%2; Loeb, Capen
and Johnson 1966; Tasker, Whiteman and Martin 1966;
Baker and Ritchie 1974; Pauli, Rossi and Straub 1974; Moore,
Steiss, Nicholson and Orth 1979). Diabetes mellitus, associated with chronic pancreatitis, was reported in a horse with
hyperglycaemia, glycosuria and ketonuria (Jeffrey 1969).
Other reported cases were not examined fully to determine the
underlying cause of hyperglycaemia (Jorgenson 1921 ; Wilkinson 195...
Garcia MC, Beech J.Intravenous glucose tolerance testing (0.5 g/kg of body weight) was done on 2 groups of healthy horses maintained with hay (group 1, n = 5) and with hay plus grain supplementation (group 2, n = 5) and on a group of horses with clinically diagnosed pituitary adenoma (group 3, n = 10). Healthy horses showed an immediate increase of plasma glucose concentration after the IV glucose injection, with return of values to base line in 1 hour. Group 3 horses showed resting hyperglycemia and a delayed return of glucose values to base line (3 hours). Group 3 horses showed resting hyperinsulinemia and a f...
Jacob RJ.Preliminary experiments have revealed that several laboratory and wild-type strains of the equine herpesvirus (EHV) triad were temperature-sensitive for growth when assayed at 39 degrees C. The efficiencies of plating (EOP) observed were 10(-2) for both EHV 1 and 2, and 1 X 10(-6) for EHV 3. The EOPs were determined by plaque assays which compared titrations at 34 degrees C and 39 degrees C on equine fetal dermal fibroblast cells. Growth yield experiments, assayed at 34 degrees C, reflected those EOP's, but did not indicate any difference in yields when infected cultures were incubated at 34 d...
Juillerat MA, Taniuchi H.To investigate the role of evolutionarily invariant leucine 32 of horse cytochrome c, analogs of residues 28-38, (28-38), each containing a substituted amino acid at positions 32 or 35 were synthesized using Merrifield's method. Position 35 is leucine in horse cytochrome c but replaced by nonpolar amino acids in some species. The ability of the analogs to bind to the two-fragment complex of ferri- or ferro heme fragment (1-25)H and apofragment (39-104) was measured using gel filtration and equilibrium dialysis. Replacement of leucine 32 with isoleucine, for example, increased the dissociation ...
Knospe C, Budras KD.To answer the many open questions concerning the development of the horse's ovary, first the prenatal development was investigated. It resulted that follicles derive from the germinal epithelium and its cords, whereas the Leydig cells and the rete blastema originate from the mesonephros. In the second third of pregnancy the Leydig cells undergo an enormous proliferation, in the last third they degenerate. However this degeneration is not connected with the postnatal development of the ovulation groove.
Wirtu G, Bailey TL, Chauhan MS, Parker NA, Dascanio JJ, Gwazdauskas FC, Ley WB.The in vitro production (IVP) of equine embryos using currently available protocols has met limited success; therefore investigations into alternative approaches to IVP are justified. The objective of this study was to evaluate the feasibility of xenogenous fertilization and early embryo development of in vitro matured (IVM) equine oocytes. Follicular aspirations followed by slicing of ovarian tissue were performed on 202 equine ovaries obtained from an abattoir. A total of 667 oocytes (3.3 per ovary) were recovered from 1023 follicles (recovery rate, 65%). Oocytes underwent IVM for 41 +/- 2 h...
Mäkinen A, Katila T, Kuokkanen MT.Only one X chromosome was found in each of the lymphocyte metaphases studied in an infertile mare. Karyotype analysis was made with the CBG and GTG banding techniques. The most obvious clinical abnormality was gonadal hypoplasia.
Henry JS, Lance VA, Conlon JM.Within the order Perissodactyla, the primary structure of insulin has been strongly conserved. Insulin from Przewalski's horse and the mountain zebra (suborder Hippomorpha) is the same as that from the domestic horse and differs from insulin from the white rhinoceros and mountain tapir (suborder Ceratomorpha) by a single substitution (Gly-->Ser) at position 9 in the A-chain. A second molecular form of Przewalski's horse insulin isolated in this study was shown to represent the gamma-ethyl ester of the Glu17 residue of the A-chain. This component was probably formed during the extraction of the...
Liu SH, Cheng F, Fan X, Li K, Hu D, Ma Y, Li H, Bayinchahan G.The genetic diversity of Gasterophilus pecorum populations consisting of 192 individuals sampled from Przewalski's horses (Equus ferus przewalskii) in Xinjiang Province, China, was evaluated using 12 microsatellite loci. The genetic variability within populations and genetic differentiation among populations were estimated. A total of 163 alleles were detected and the average value of observed number of alleles at each locus ranged from 7 to 19 (average 13.5625). The expected heterozygosity (He) varied from 0.5933 (GP361) to 0.9208 (GP253) and averaged 0.8426. The effective number of alleles (...