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Topic:Genetics
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.
Comparison of the lipoprotein profiles obtained from rat, bovine, horse, dog, rabbit and pig serum by a new two-step ultracentrifugal gradient procedure. A new two-step gradient technique has been used in the separation of the different classes of lipoproteins from the serum of cows, horses, dogs, pigs, rabbits and rats. Total lipoproteins were first isolated at d 1.21 then floated through a d 1.006 to d 1.21 gradient. Collection by mean of a gradient fractionator provided directly comparable lipoprotein profiles, allowed the determination of the exact density range of each lipoprotein class and the fraction by fraction analysis of composition. Cholesterol and apo AI recoveries were high. Horse, dog, rabbit and pig exhibited three distinct lipo...
Genetic linkage between loci for a red cell alloantigen (U) and serum protease inhibitor (Pi) in the horse. Preliminary evidence for the fifth autosomal linkage group in the horse, comprised of the loci for a red cell alloantigen (U) and serum protease inhibitor (Pi), was demonstrated by means of paternal half-sib groups in thoroughbred, standardbred and Arabian breeds. Recombination frequency in males was estimated to be 0.125 +/- 0.019.
Segregation distortion within the equine MHC; analogy to a mouse T/t-complex trait. Segregation distortion was found for a haplotype of the equine lymphocyte antigen (ELA) system in an extended family of American Standardbred horses. In one sire family, consisting of a stallion and his 17 sons and grandsons, the gene for ELA-A10 (A10) was transmitted to 57.7% of 638 offspring scored (P = 0.001). Significant segregation distortion was not seen for mares or for unrelated stallions, regardless of the ELA markers they possessed. Since the effect was seen for this one sire family and not seen for other stallions with A10, it is unlikely that the gene for A10 is the cause of this p...
Bilateral salpingitis, hydrosalpinx and oophoritis in a mare. Bilateral salpingitis, hydrosalpinx and oophoritis were diagnosed in a mare with concurrent lymphosarcoma. Salpingitis, hydrosalpinx and oophoritis are rare in the mare (1,2,3,5,8,9,11-13). Bilateral salpingitis is an important cause of infertility in all species and is most often due to ascending infection (3-5,10,11). The source of salpingitis in this mare probably was ascending infection from the uterus after parturition. The apparent infertility of the mare was attributed to debilitation from the lymphosarcoma and multiplicity of genital pathoses.
Comparison of antiproteolytic activities of alpha-1-proteinase inhibitors from the plasma of some mammalian species. Alpha-1-proteinase inhibitors isolated from plasmas of horse, ox, pig, rabbit and man were used for determination of some kinetic parameters of interaction with three horse leucocyte proteinases and bovine pancreatic trypsin and chymotrypsin. Effective molar ratio of enzyme-to-inhibitor, inactivation rate constant and inhibition constant were measured. In horse, ox, pig and rabbit two principal electrophoretic forms of alpha 1-PI could be distinguished. Both forms effectively inhibited trypsin but usually only one form reacted promptly and stoichiometrically with chymotrypsin and leucocyte ela...
Electrophoretic polymorphism and molecular structure of equine C3. 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...
Comparison of specificity of human and horse leucocyte proteinases with synthetic peptide substrates. Highly purified horse leucocyte proteinases 1, 2A and 2B hydrolyze synthetic substrates which are decomposed also by human leucocyte elastase but they are unable to hydrolyze typical substrates of cathepsin G. Thus in distinction to other mammalian species horse leucocytes are devoid of cathepsin G and contain only elastases.
XY sex-reversal syndrome in the domestic horse. The XY sex-reversal syndrome occurs when a phenotypic mare is born that has the karyotype of a stallion. The syndrome is manifested by both genotypic and phenotypic heterogeneity. The sex-reversed genetic condition occurs frequently within certain pedigrees where XY females have been found and can be readily detected by chromosome karyotyping. The phenotypic spectrum ranges from the feminine mare with a reproductive tract that is within normal limits to the greatly masculinized mare. Pedigree analysis suggests that there are two modes of inheritance: (1) an X-linked recessive or autosomal sex-...
A soluble class I molecule analogous to mouse Q10 in the horse and related species. Horse serum is shown to contain a soluble class I molecule analogous to the secreted Q10 molecule in the mouse. This molecule has several similarities to the recently described mouse Q10 molecule: it is smaller than membrane-bound equine class I molecules; it occurs in a high molecular mass complex of 200-300 kd in serum; and the serum levels of the equine molecule are similar to that of the Q10 molecule (about 30 micrograms/ml). A soluble molecule is also detected in the sera of species related to the horse; it has in fact been found in all the wild members of the order Perissodactyla so far ...
Polymorphic restriction sites in the horse beta-globin gene cluster. Horse DNA samples digested with PstI and probed with the rabbit beta 1 globin gene show three phenotypes determined by one fragment of variable length (about 5.1 or 3.3 kb). Family data demonstrate that these fragments segregate as Mendelian alleles. The frequencies of the two alleles are 0.66 for the 3.3-kb fragment and 0.34 for the 5.1-kb one. Another polymorphism has been detected with BamHI. Again three phenotypes determined by two alleles (fragments of 7.5 and 3.8 kb) have been observed. Allelic frequencies of the 7.5- and 3.8-kb fragments are 0.24 and 0.76 respectively. The two polymorph...
[Chaetotaxy of Gastrodiscus aegyptiacus cercaria (Trematoda, Paramphistomoidea) a horse parasite]. Cercarial chaetotaxy of Gastrodiscus aegyptiacus (Paramphistomoidea), parasite of the Horse, is described. Cercariae were shed by experimentally infected Bulinus forskalii. This description is the first one of a Gastrodiscidae. The cercarial chaetotaxy of the Gastrodiscidae is quite different from those of Paramphistomoidea and Diplodiscidae.
Phalangeal and navicular bone hypoplasia and hoof malformation in the hind limbs of a foal. Anatomical anomalies in the hind feet of a seven month old Appaloosa foal were identified and investigated through the use of gross anatomical dissection, radiography and angiography. Abnormalities were restricted to the distal aspect of both hind legs, the right hind leg being more severely affected. Anatomically the right foot resembled that of an equine fetus of approximately 120 days gestational age. Disruption of vascular perfusion to hoof structures was evident in both hind legs and was related to areas of abnormal bone conformation as well as to areas of abnormal ossification and calcif...
DNA polymorphism in the major histocompatibility complex of man and various farm animals. In the past few years it has been possible by combining enzymatic cleavage of genomic DNA and the Southern blot hybridization technique to explore the endonuclease recognition site polymorphism of the MHC. HLA class I and DR and DQ alpha and beta class II specific probes as well as human C4 and Bf class III probes were used. All these probes were shown to cross-hybridize with DNA from pigs, cattle, sheep and horses. Hybridization of human genomic DNA with a class I probe showed 15-25 bands per genome depending on the enzyme used. Distinct endonucleases generated clusters of restriction fragmen...
Spontaneous expression of an endogenous retrovirus by the equine sarcoid-derived MC-1 cell line. A retrovirus is spontaneously released into the culture medium of the equine sarcoid-derived MC-1 cell line. The MC-1 virus did not exhibit in vitro transforming activity or replication when tested on equine fibroblasts or a variety of other mammalian cell cultures. Complementary DNA, synthesized using detergent-activated MC-1 virus RNA-dependent DNA polymerase, detected homologous sequences in the DNA of an established equine dermal cell line and in the DNA of primary equine dermal fibroblasts. Iododeoxyuridine or azacytidine induced a replication-deficient endogenous retrovirus in the normal...
Equine leukocyte antigens: relationships with sarcoid tumors and laminitis in two pure breeds. Frequencies of equine leukocyte antigen distribution were determined by complement-mediated cytotoxicity testing among populations of Thoroughbred and Standardbred horses, including animals affected with equine sarcoid and laminitis. A highly significant association is described between the presence or history of sarcoid lesions in Thoroughbreds and the expression of the major histocompatibility complex (MHC)-encoded antigens, W3 and B1. No association was found between antigenic expression frequencies and laminitis in either breed. These findings suggest that a strong relationship exists betw...
Rapid emergence of novel antigenic and genetic variants of equine infectious anemia virus during persistent infection. Previous results from our laboratory have demonstrated that equine infectious anemia virus displays structural variations in its surface glycoproteins and RNA genome during passage and chronic infections in experimentally infected Shetland ponies (Montelaro et al., J. Biol. Chem. 259:10539-10544, 1984; Payne et al., J. Gen. Virol. 65:1395-1399, 1984). The present study was undertaken to obtain an antigenic and biochemical characterization of equine infectious anemia virus isolates recovered from an experimentally infected pony during sequential disease episodes, each separated by intervals of ...
Heredity of navicular disease. Bone structure, nutrient canals, form and definition, and a total evaluation of both fore navicular bones were radiologically evaluated in 169 three- and four-year-old Dutch warmblood mares divided into eleven daughter (half sister) groups. On the basis of the 'total evaluation', differences between the three- and four-year-old horses were detectable. Using the 'total evaluation', significant differences were found between daughter groups consisting of three-year-old mares. These differences support the theory that podotrochleosis may be (partly) due to the presence of genetic factors. The pos...
Comparison of neutrophil elastases and of neutrophil protease inhibitors in the horse and man. Neutral neutrophil protease, elastase activities, and cytosol protease inhibitors of these enzymes of horses and man were compared. Human neutrophils had 5 times the elastase activity of equine neutrophils, and neutral protease activity was approximately 50% greater in human neutrophils than that in equine neutrophils. Cytosol inhibitors for elastase and neutral proteases were not found in human neutrophils, whereas large amounts were found in equine neutrophils. Using fibrinogen-agarose electrophoresis, 4 cytosol inhibitors of different enzyme specificities were detected. These cytosol inhibi...
Identification of 3 beta-hydroxy-5,7-androstadien-17-one as a secretory product of the fetal horse gonad in vivo and in vitro. Isolation of 3 beta-hydroxy-5,7-androstadien-17-one, as a major component of steroids extracted from vein blood of the fetal gonads of the horse, supports the proposed role for the compound as a precursor for equilin formation in the placenta of the mare. The 5,7-diene was extracted from blood collected from gonadal veins of fetal ovaries and testes in situ, and from a fetal testis connected to an artery in the neck region of the mare. Perfusion of fetal gonads in the laboratory was carried out to allow longer periods of collection. In addition, isolated cell preparations from a fetal testis w...
Sequences of papillomavirus DNA in equine sarcoids. DNA was extracted from 14 equine sarcoids, electrophoresed and hybridised with a radioactively labelled probe of bovine papillomavirus type I (BPV 1) DNA under conditions of low stringency. Twelve sarcoids contained sequences of DNA that hybridised with the probe and that comigrated with BPV 2 DNA. The viral DNAs in four of these sarcoids differed from BPV 1 and BPV 2 DNA on restriction endonuclease analysis. One of four cell lines derived from sarcoids also contained BPV 1 related DNA. The results confirm the frequent presence in equine sarcoids of unintegrated papillomaviral DNA and suggest ...
Fibronectin enhances transfection of Staphylococcus aureus. The factor in normal sera primarily responsible for the enhancement of transfection (and transformation) of Staphylococcus aureus was identified as fibronectin. Serum samples which were depleted of fibronectin by affinity chromatography showed a marked decrease in enhancing activity. Fibronectin isolated from sera of several animal species demonstrated enhancing activity.
Lymphadenopathy-associated virus: from molecular biology to pathogenicity. Recent data indicate that the lymphadenopathy-associated virus (LAV) is morphologically similar to animal lentiviruses, such as equine infectious anemia and visna viruses. This finding, together with the cross-reactivity of the core proteins of LAV with those of the equine infectious anemia virus and a similarity in genome structure and biological properties, allows LAV to be placed in the retroviral subfamily of Lentivirinae. Molecular data indicate a high degree of genetic variation of the virus, especially in the envelope gene, which have important implications for the origin of the virus (...
