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.
Lazary S, Gerber H, de Weck AL, Arnold P.A new, non-MHC linked alloantigenic membrane antigen on the equine lymphocytes is described. This antigen was characterized with alloantisera in the two-stage microcytotoxicity test and designated as ELy-1 antigen. The frequency of ELy-1 antigen positive animals in various populations is close to 50%. ELy-1 shows an autosomal, dominant inheritance. Since an allelic antigen (s) could not be demonstrated in family studies, it is assumed that only two alleles ELy-1+ and ELy-1- exist. The ELy-1 antigen in positive animals is expressed on both T and B lymphocytes but it is not present on erythrocyt...
Ronéus B.When blood selenium concentrations and glutathione peroxidase activity was measured in 30 standardbred horses a significant correlation was found (r = 0.97). A comparison between blood GSH-px activity in clinically healthy foals, foals affected by muscular dystrophy (MD) and their respective mares was also done. There was no difference in GSH-px activity between the healthy foals and the MD foals or between the corresponding mares.
Swift RV, Mottironi VD.Lymphocytes from an extended family of Welsh ponies were tested in a microcytotoxicity test against Thoroughbred and Arabian horse-derived antisera, which defined 4 and 6 equine lymphocyte antigen (ELA) specificities, respectively. Mixed leukocyte culture (MLC) tests were also performed. Welsh pony lymphocytes reacted to the Thoroughbred antisera. Most of the ponies' lymphocytes showed reactivity to 2 of the Thoroughbred ELA specificities, the offspring inheriting 1 antigen from each parent. Antigenic determinants were only partially demonstrated with Arabian antisera, although results indicat...
Atherton JG, Pitt TL.Pseudomonas aeruginosa isolates from equine clinical material were categorised according to their serotype and phage type. Epidemiological evidence showed that serotypes 02a, 03, 04, 06, 09 and 010 were the cause of genital and non-genital infections; somatic type 03 accounted for 50 per cent of isolates. The laboratory tests used were of no value in predicting whether or not a particular isolate was likely to be a venereal pathogen, but all the serotypes encountered had the potential to be pathogenic, given a favourable environment in which to multiply.
Skok MV, Denisiuk PV, Komissarenko SV.Glutaraldehyde treatment does not change the absorption of cytochrome c either in the visible or in UV spectra. It brings about the formation of dimers, trimers and high-polymeric forms of cytochrome c and shifts the pI of all cytochrome c isoelectric fractions to more acid pH. Polymerization also results in changes of kinetic parameters of cytochrome c benzidine reaction increasing its affinity to 3,3-diaminobenzidine with a simultaneous decrease in the effectiveness of H2O2 binding. These biochemical changes can be related to immunochemical differences of native and glutaraldehyde-treated cy...
Yilma T, Perryman LE, McGuire TC.The results of a study on the induction of IFN-alpha, IFN-beta, and IFN-gamma in normal and SCID foals showed a deficiency of IFN-gamma but not IFN-beta in SCID foals. The ability of SCID mononuclear cells to produce IFN-alpha in response to poly I:C but not to NDV may indicate a partial deficiency of IFN-alpha in SCID foals. The deficiency of IFN-gamma and presence of IFN-beta in SCID foals supports the classification of IFN-gamma and IFN-beta as immune and nonimmune interferons, respectively. Furthermore, the deficiency of IFN-gamma in SCID foals may in part explain the high susceptibility t...
Antczak DF, Bright SM, Remick LH, Bauman BE.A genetic system controlling lymphocyte alloantigens of the horse is described. Alloantisera to paternal histocompatibility antigens induced as a result of pregnancy in mares were used in an antibody-mediated complement-dependent microcytotoxicity assay to define 15 Equine Leukocyte Antigen (ELA) specificities using cluster analysis. In this study 369 sera were screened for alloantibody using lymphocytes from 10 randomly selected, unrelated horses. A high proportion (83%) of these sera were found to be positive for antibody to lymphocyte alloantigens. After initial cluster analysis, 120 of the...
Ginther OJ, Douglas RH, Lawrence JR.Responses of 22 veterinarians to a questionnaire and the records of three brood-mare farms were examined to obtain information on twinning. The incidence rates of multiple ovulations on the three farms were 9%, 11%, and 22%. The multiple ovulation rate was reduced 42-67% in foaling mares compared to barren and maiden mares. Multiple ovulations were significantly more frequent in Thoroughbreds (19%) than in Quarter Horses (9%) and Appaloosas (8%). Both the questionnaire and the farm records indicated a high degree of repeatability of multiple ovulations and twin pregnancies within mares and wit...
Tuthill RJ, Clark WH, Levene A.A unique pigmented lesion, judged to be a hamartoma of neural crest origin, occurring in a female patient, is compared with equine melanotic disease, The characteristic perifollicular arrangement of pigment-laden spindle cells is remarkably similar in both. Previously described patch- and plaque-like blue nevi in humans are also closely related. Light and ultrastructural features showed differentiation toward both nevus cells and Schwann cells, and it is proposed that the lesion be termed pilar neurocristic hamartoma.
Poskus E, Peña C, Pérez AR, Vita N, Heinrich JJ, Paladini AC.The immunological behavior of sera from hypopituitary patients treated with human GH (hGH) has been studied by homologous and heterologous RIAs using 125I-labeled hormones. Along with antibodies against hGH, antibodies exhibiting antibovine and antiequine GH (anti-bGH and anti-eGH, respectively) activities were also found. Displacement experiments showed that hGH was an effective competitor of 125 I-labeled hGH, whereas bGH and eGH were quite inefficient. Conversely, when the tracer was 125I-labeled bGH, both bGH and eGH were good displacers, while the human hormone was poor. The values of the...
Moudgal NR, Papkoff H.The ability of equine luteinizing hormone (eLH) to promote follicular growth and maturation in hypophysectomized rats has been assessed. A single injection of equine LH has been shown to promote the growth of a large number of antral and preovulatory follicles. In addition, equine LH markedly increased serum estrogen levels and uterine weight. Furthermore, equine LH, like equine chorionic gonadotropin (eCG; PMSG) was able to significantly enhance the incorporation of [3H]thymidine into ovarian DNA, an activity shown to be specific to hormones having follicle-stimulating hormone (FSH) activity....
Pinna AE, Okada CTC, Ferreira CSC, Campos DG, Possidente KS, de Cássia C L Morais R, Oliveira M, Salomão MC, Hataka A.Ovarian tumours in mares represent 2.5% to 6% of the most frequent neoplasms found in the equine species, with a higher chance of benignity. This study aims to describe a case of two different tumours found in the same ovary of a mare that presented clinical signs of suppressed oestrous cycle during 5 years. After unilateral ovariectomy, the ovary was sent to the histopathology examination which determined a mixed tumour of granulosa cell and leiomyosarcoma. After treatment, the mare returned to oestrus and got pregnant in the next season.
Marlow CH.Horse breeding in South Africa started in 1652, shortly after the 1st European settlement in the Cape. African horsesickness posed a serious problem and after a devastating outbreak of the disease in 1719, horses were largely replaced by oxen for agricultural and transport purposes but remained important from a sporting and military point of view. Examples of the latter are the export of horses for military use to India in the mid-19th century and for use in the Crimean War in 1854, reaching a zenith in the Anglo-Boer war in which an estimated 450 000 horses succumbed. Research and disease con...
Patterson-Kane JC, Ginn PE.The current report describes a malignant melanoma in the dermis of a 13-year-old bay Thoroughbred mare. Microscopic examination revealed that tumor cells were arranged in cords and packets within an abundant collagenous stroma containing scattered myxomatous foci. Tumor cells stained positively for S-100, neuron-specific enolase, and vimentin and some contained melanin granules. Some clusters of tumor cells were also positive for pancytokeratin. Expression of epithelial cell markers has been described in small numbers of human melanomas but has not been reported previously in equine melanomas....
Möller R, Graglia F, Pizzigatti D, van Lier E.Horses went through functional differentiation during their evolutionary and reproductive development, however, some body parts continued to improve their specificity for speed. Regarding this, we evaluated by morphometric analysis the relationship between limb section (LS) differences in the appendicular structures of horses. Two hundred and seven (n = 207) adult horses of different breeds and sex were selected. The limb section was measured by identification of topographic palpable skeleton landmarks with a measurement tape (centimetres). Quantitative variables (limb section) were analysed...
Stewart RH, Bertone JJ, Yvorchuk-St Jean K, Reed SM, Neil WH.Hyperkalemic periodic paralysis (HPP), characterized by intermittent episodes of muscle fasciculations, profound muscle weakness, and hyperkalemia, has been described in Quarter Horses, Appaloosas, and Paints. In previous reports, the hallmark of this syndrome has been the development of hyperkalemia during each episode. Two affected horses had episodes of paralysis without associated hyperkalemia, demonstrating that normokalemia during an episode otherwise consistent with HPP does not eliminate HPP as a diagnosis. This clinical presentation appeared to be a variant of HPP.
Pirhonen A, Linnala-Kankkunen A, Kenney RM, Mäenpää PH.Protamine P1 amino acid sequences were determined from semen samples of the Przewalski horse, donkey, Somali wild ass, Grevy's zebra, and Grant's zebra (odd-toed perissodactyls), and compared with those of the domestic horse. Although the rate of amino acid variation of protamine P1 is known to be among the most rapidly diverging polypeptides, the equid sequences revealed only little variation. The sequence from the Przewalski horse was identical with that from the domestic horse. The other sequences differed from the corresponding sequences of the domestic and Przewalski horses in two positio...
Adams GP, Bosu WT.This article reviews the reproductive events in the nonpregnant mare with emphasis on recent advances. The discussion is restricted to the salient features of puberty (prenatal and prepubertal events), seasonality (gonadotropins, photoperiod, and other modifying factors), and the estrous cycle (hormones, estrus, diestrus, and the control of cyclicity) in the nonpregnant mare.