Genetic variants in horses refer to differences in the DNA sequence among individuals within the species. These variants can affect various traits, including coat color, performance, and susceptibility to diseases. Research on equine genetic variants involves identifying and understanding these differences and their implications for horse breeding, health, and management. Studies often focus on single nucleotide polymorphisms (SNPs), copy number variations (CNVs), and other genetic markers that can influence phenotypic traits. This page aggregates peer-reviewed research studies and scholarly articles that explore the identification, characterization, and impact of genetic variants on equine biology and health.
Naylor JM.The purpose of this review is to present an up-to-date summary of the signs, diagnosis, treatment, and implications of equine hyperkalemic periodic paralysis. The review encompasses all original articles published between 1986 and early 1993. Hyperkalemic periodic paralysis is the result of a genetic mutation in the skeletal muscle sodium channel gene. It is inherited as an autosomal dominant trait; most affected horses are heterozygotes. The classical signs are muscle fasciculation, spasm, and weakness associated with hyperkalemia. However, these signs are only rarely observed in affected hor...
Bonass WA, Hudson WA, Elton DM, Killington RA, Halliburton IW.Restriction enzyme digests of DNA from 22 unselected isolates of EHV-1 were analysed by hybridization with cloned DNA fragments covering the genome. In addition to a small amount of inter-strain variation, heterogeneity within strains was observed, caused by loss of specific restriction endonuclease sites in the DNA of a proportion of the virus particles of any one stock. Fifteen strains demonstrated the same intra-strain variation involving loss of the BamHI L-M site which was shown to lie within coding sequence for the large subunit of ribonucleotide reductase. This particular mutation may t...
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...
Wilke K, Weimann M, Jung M, Geldermann H.10 different oligonucleotide probes were evaluated for DNA fingerprinting in horses. Five probes were able to detect polymorphic bands. The probes (GT)(8) , (GTG)(5) and (GGAT)(4) are most informative for individual identification and were used to analyze a population of Hannoveranian horses. The probability that two individuals have the same DNA fingerprint pattern is 1.2 × 10(-8) , 5.2 × 10(-10) and 1.5 × 10(-7) respectively. Using a combination of the three probes, paternity tests were performed with exclusion probabilities between 0.08% and 4%. ZUSAMMENFASSUNG: Oligonukleotide-Sonden fÃ...
Ambros'eva ED, Khokhriakova ZhA, Glazko VI.The genetic structures of Orlov's and Russian trotters for 16 biochemical systems have been comparatively analyzed. Polymorphism of 6 systems of these horse groups is revealed. The main genetic differentiation between Orlov's and Russian trotters is observed on the transferrin and phosphoglucomutase loci.
Ellegren H, Johansson M, Sandberg K, Andersson L.We have isolated equine microsatellites by screening a genomic library with (TG)n and (TC)n probes. TG microsatellites were found to be more abundant than TC repeats, with an estimated frequency of one per 100,000bp. Sequence analysis of eight TG-positive clones revealed varying structures of the repeat regions; perfect stretches of TG repeats, imperfect stretches of TG repeats and compound regions of TG and TC repeats. Five loci were analysed by PCR and showed extensive polymorphism; three to seven alleles and heterozygosities of 0.40-0.76 were observed when screening 20-30 unrelated individu...
Field HJ, Awan AR, de la Fuente R.The compound (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA) had been previously shown to be highly effective in treatment of EHV-1 in a murine model for the equine disease. This paper describes the isolation of a series of mutants resistant to the drug. Resistance was demonstrated in cell culture and one mutant was tested in a murine model. The resistant mutant was pathogenic for mice; infectious virus was recovered from respiratory tissues and blood at levels similar to the parental virus. However, the mutant showed a significant degree of resistance in vivo, thus proving the viru...
Yon JM, Desmadril M, Betton JM, Minard P, Ballery N, Missiakas D, Gaillard-Miran S, Perahia D, Mouawad L.Flexibility and folding of phosphoglycerate kinase, a two-domain monomeric enzyme, have been studied using a wide variety of methods including theoretical approaches. Mutants of yeast phosphoglycerate kinase have been prepared in order to introduce cysteinyl residues as local probes throughout the molecule without perturbating significantly the structural or the functional properties of the enzyme. The apparent reactivity of a unique cysteine in each mutant has been used to study the flexibility of PGK. The regions of larger mobility have been found around residue 183 on segment beta F in the ...
Kashi Y, Tikochinsky Y, Genislav E, Iraqi F, Nave A, Beckmann JS, Gruenbaum Y, Soller M.Southern blots of genomic DNA from a variety of species digested by restriction endonucleases having a four-bp specificity, were probed with a bovine genomic clone consisting of seven tandem poly-TG stretches separated by a 29bp linker sequence. Highly variable DNA 'fingerprint' patterns were obtained in chicken, sheep, and horse, moderately variable DNA 'fingerprints' in mouse and man, and a monomorphic pattern in Drosophila. In chicken, horse and man a (TG)10 synthetic oligonucleotide probe gave results identical to those given by the bovine probe. Furthermore, in chicken the DNA fingerprint...
Patton S, Huston GE, Jenness R, Vaucher Y.Milk fat globules are secreted by envelopment in plasma membrane of the lactating cell. SDS-gel electrophoresis of proteins from this membrane has revealed differences between milk donors in two mucin-like glycoproteins. One of these glycoproteins resolves in 3% acrylamide stacking gel and the other in 4% running gel. The proteins vary in number of bands (one or two) and band mobilities. This polymorphism arises, at least in part, from expression of hypervariable genes. In this study, gel electrophoretic evidence of similar polymorphism in glycoproteins from cow, chimpanzee, horse and human mi...
Juneja RK, Gahne B, Lukka M, Ehnholm C.By using immunoblotting with antiserum specific to human plasma apolipoprotein A-IV (apoA-IV), a previously reported polymorphic plasma protein of dogs viz postalbumin-2 (Pa2) and one of horses viz serum protein 2 (SP2), were identified as apoA-IV of these species. This along with earlier published results implied that: (1) both dog and horse show a high degree of polymorphism at the APOA4 locus with three common alleles in each of the two species; and (2) apoA-IV phenotyping in these two species can be done by analysing plasma/serum samples by a simple method of two-dimensional electrophoresi...
Clegg JB.A new member (theta 1, or psi alpha) of the alpha-globin gene family has recently been identified in a number of species. In higher primates the theta 1 gene has all the structural features apparently necessary for expression, and it appears to have long been under strong selective constraints which suggests that it could still be, or recently have been, a functional gene. No corresponding 'globin' has yet been identified, however. In some other species, galago and rabbit for example, the theta 1 and psi alpha genes have accumulated enough inactivating mutations for them to be considered genui...
Kay PH, Dawkins RL, Bowling AT, Bernoco D.A cDNA probe to the alpha subunit of the murine acetylcholine receptor was used to demonstrate restriction fragment length polymorphism in an acetylcholine receptor gene in the horse. Three different patterns of polymorphism have been observed with fragment sizes of 4.3 and 2.9 kilobases (kb) (pattern 1), 4.3 and 2.5 kb (pattern 2) and 4.3, 2.9 and 2.5 kb (pattern 1,2). Analysis of a three generation pedigree has suggested that patterns 1 and 2 represent two allelic forms of the gene encoding the alpha subunit of the acetylcholine receptor. These data provide a basis for the examination of the...
Andersson L, Arnason T, Sandberg K.Investigations on relationships between biochemical polymorphism and variation in quantitative traits are of interest from the perspectives of both theoretical quantitative genetics and practical animal breeding. This subject was studied by using racing performance records of more than 25,000 horses of the Swedish Trotter breed born in the period 1970-1979. For all horses data on six blood group and nine electrophoretic loci were available. Two different performance traits were investigated. A racing performance index value was calculated for all individuals which had started in at least five ...
Alexander SL, Irvine CH, Turner JE.FSH was measured in the pituitary, and in pituitary venous and jugular blood collected at frequent intervals from mares in various reproductive states, using 3 validated and highly specific radioimmunoassay systems based on different antibodies, 'o', 'h' and 'e'. In the pituitary, 4 forms of FSH were found which differed in isoelectric point and relative potency in the 3 assays. In jugular blood, mean FSH concentrations and short-term patterns depended on the assay used and the reproductive state of the mare. In pituitary venous blood, although FSH concentrations were greatly elevated above ju...
Weitkamp LR, Costello-Leary P, Guttormsen SA.Polymorphism for two autosomal alleles of equine plasminogen, PLG1 and PLG2, was demonstrated in plasma by isoelectric focusing and immunofixation, with a goat anti-human plasminogen antibody. The frequency of PLG2 was 0.16 in 150 Standardbreds, 0.20 in 96 Thoroughbreds, and 0.39 in 32 Shetland ponies. No evidence for linkage of PLG with any of 13 marker loci was found.
Guttormsen SA, Weitkamp LR.Polymorphism of equine erythrocyte malic enzyme is detactable on starch gel electrophoresis. The frequency of ME1S was 0.06 in 667 Standardbred and 0.09 in 85 Thoroughbred horses. No genetically determined electrophoretic variation in soluble malate dehydrogenase was detected.
Matsuda G, Maita T, Braunitzer G, Schrank B.The sequence analysis of the slow migrating component of the hemoglobins of horse was repeated with the automatic methode in the sequenator and the sequence of the beta-chains completed. In the alpha-chains the positions of alpha63 and alpha65 (Gly, Ala) and alpha82 and alpha85 (amides) were changed and the remaining 40 sequences of the beta-chains are reported. According to these data and biological contributions of other authors, the biological aspects of the primary structure and the polymorphism of the hemoglobins of the horse are discussed.
McGuire TR, Weitkamp LR.The equine transferrin F variant is distinguishable into two types, F1 and F2, on alkaline polyacrylamide gel electrophoresis. Gene frequencies in 63 related Thoroughbreds are 0.39 and 0.19 for TfF1 and TfF2, respectively. In contrast the frequencies for these two alleles in 375 related Standardbreds is 0.00 and 0.59.
Putt W, Fisher RA.In this paper we describe seven enzymes, NP, GOTM, PGM2, alpha FUC, PEP A, ADA and MPI which are found in the white cells of horses, including 39 British crossbred ponies and 16 crossbred horses, 30 Mongolian ponies and 10 Icelandic ponies. Two of these enzymes--alpha FUC and MPI--were polymorphic in all the populations of horses studied and could prove useful as additional markers in the paternity testing of horses. PEP A and GOTM were also polymorphic in two of the populations studied and could be used as further markers in these populations.
Irvine CH.Isoelectric focussing of crude extracts of equine pituitaries was used to obtain fractions containing FSH and LH. By comparison with FSH, LH was distributed over a similar but wider pH range indicating more marked polymorphism as determined from their isoelectric point (pI). Molecules with more sialic acid showed lower pI consistent with the concept that sialic acid is the major factor in determining pI and polymorphism in FSH and LH. Appropriate fractions were labelled with 125I, purified further and used in kinetic studies. FSH and LH molecules of similar pI had similar kinetics; however, LH...
Braunitzer G, Schrank B, Stangl A, Bauer C.The sequence analysis of llama (Lama glama, Camelidae) hemoglobin is described. The chains were separated, cleaved by trypsin as previously described, quantitatively characterized and sequenced in the sequenator. The llama hemoglobin differs from the human hemoglobin in that it has 25 different amino acids in the alpha chain and 24 different amino acids in the beta chain. The interaction between protein and phosphate is discussed. The earlier finding that the O2 affinity of the llama hemoglobin is dependent on its content of 2, 3-bisphosphoglycerate is interpreted here as a mutation of the 2, ...
McGuire TR, Weitkamp LR.The equine transferrin F variant is distinguishable into two types, F1 and F2, on alkaline polyacrylamide gel electrophoresis. Gene frequencies in 63 related Thoroughbreds are 0.39 and 0.19 for TfF1 and TfF2, respectively. In contrast the frequencies for these two alleles in 375 related Standardbreds is 0.00 and 0.59.
Duyn RJ, van Haeringen H.Hyperkalaemic periodic paralysis is a genetic disease that affects the American Quarter Horse population and is caused by a mutation. As a result of this mutation in a gene which codes for the sodium channel in muscle cells, severe muscle weakness can appear. Reliable DNA-tests can establish whether a horse is homozygous negative, heterozygous, or homozygous positive for this mutation. Therapy and prevention are discussed.
Kay PH, Dawkins RL, Bowling AT, Bernoco D.A cDNA probe to the alpha subunit of the murine acetylcholine receptor was used to demonstrate restriction fragment length polymorphism in an acetylcholine receptor gene in the horse. Three different patterns of polymorphism have been observed with fragment sizes of 4.3 and 2.9 kilobases (kb) (pattern 1), 4.3 and 2.5 kb (pattern 2) and 4.3, 2.9 and 2.5 kb (pattern 1,2). Analysis of a three generation pedigree has suggested that patterns 1 and 2 represent two allelic forms of the gene encoding the alpha subunit of the acetylcholine receptor. These data provide a basis for the examination of the...
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...
Andersson L, Arnason T, Sandberg K.Investigations on relationships between biochemical polymorphism and variation in quantitative traits are of interest from the perspectives of both theoretical quantitative genetics and practical animal breeding. This subject was studied by using racing performance records of more than 25,000 horses of the Swedish Trotter breed born in the period 1970-1979. For all horses data on six blood group and nine electrophoretic loci were available. Two different performance traits were investigated. A racing performance index value was calculated for all individuals which had started in at least five ...
Irvine CH.Isoelectric focussing of crude extracts of equine pituitaries was used to obtain fractions containing FSH and LH. By comparison with FSH, LH was distributed over a similar but wider pH range indicating more marked polymorphism as determined from their isoelectric point (pI). Molecules with more sialic acid showed lower pI consistent with the concept that sialic acid is the major factor in determining pI and polymorphism in FSH and LH. Appropriate fractions were labelled with 125I, purified further and used in kinetic studies. FSH and LH molecules of similar pI had similar kinetics; however, LH...
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...
Kumar S, Ashraf M, Pannu U, Mehta SC.In equines, muscle exercise highly affects the expression of genes which are associated with secretion of cytokines. Myokines are the group of cytokines that are produced by skeletal muscles during exercise. Interleukin-6 (IL-6) and Interleukin-8 (IL-8) are among such myokines. This study was therefore taken up in 42 animals of Marwari, Kathiawari, Manipuri and Zanskari horses; and Poitou and Halari donkeys to find out the Single Nucleotide Polymorphisms (SNPs) in the IL-6 and IL-8 genes. Sequence analysis of exon 2 of IL-6 gene revealed an intronic SNP (C>T) at position Equcab3.0:4:54607583 i...
Mang L, Li JL, Shi YF.Mitochondrial DNA D-Loop varied region 400 bp sequence variations in 4 Chinese Mongolian horses and 4 External Thoroughbred horses were analyzed in this experiment. The results showed that the average nucleotide mutational rate of mtDNA D-Loop varied region in 4 Chinese Mongolian horses was 3.69%, while External Thoroughbred horses were 4.00%. Three types of mutations including transition, transversion and deletion were all found in the investigated mtDNA D-Loop regions, of which transition was the most frequent. Nucleotide mutational loci were abundant, length mutations were found and great d...
White SD, Bourdeau P.Hereditary equine regional dermal asthenia (HERDA) in Quarter Horses is an inherited degenerative skin disease. Initially reported as hyperelastosis cutis, HERDA has a phenotype of hyperextensible, fragile skin, with secondary seromas, haematomas, ulcers and scarring. It primarily affects the dorsal aspect of the body. An autosomal recessive mode of inheritance is considered likely, with affected horses more at risk to produce affected offspring. A mutation in cyclophilin B (PPIB) as a novel, causal candidate gene for HERDA has been described, and verified as segregating with carriers and affe...
Wilke K, Weimann M, Jung M, Geldermann H.10 different oligonucleotide probes were evaluated for DNA fingerprinting in horses. Five probes were able to detect polymorphic bands. The probes (GT)(8) , (GTG)(5) and (GGAT)(4) are most informative for individual identification and were used to analyze a population of Hannoveranian horses. The probability that two individuals have the same DNA fingerprint pattern is 1.2 × 10(-8) , 5.2 × 10(-10) and 1.5 × 10(-7) respectively. Using a combination of the three probes, paternity tests were performed with exclusion probabilities between 0.08% and 4%. ZUSAMMENFASSUNG: Oligonukleotide-Sonden fÃ...
The Journal of heredityNovember 25, 2009
Volume 101, Issue 2 246-250 doi: 10.1093/jhered/esp091
Mittmann EH, Lampe V, Mömke S, Zeitz A, Distl O.The availability of a high-quality draft sequence of the horse makes known the physical location of microsatellites. The aim of the present study was to establish a highly polymorphic minimal screening set of microsatellite markers for horses (MSSH) annotated on the horse genome assembly EquCab2.0. We have used the previously reported linkage and radiation hybrid maps and have extended these marker sets by filling in gaps as noted from annotation on the horse sequence. This MSSH covers all autosomes and the X chromosome with 322 evenly spaced microsatellites whose positions were determined on ...
Steward KF, Harrison T, Robinson C, Slater J, Maskell DJ, Harris SR, Holden MTG, Waller AS.Opportunistic pathogens must adapt to and survive in a wide range of complex ecosystems. Streptococcus zooepidemicus is an opportunistic pathogen of horses and many other animals, including humans. The assembly of different surface architecture phenotypes from one genotype is likely to be crucial to the successful exploitation of such an opportunistic lifestyle. Construction of a series of mutants revealed that a serine recombinase, PinR, inverts 114 bp of the promoter of SZO_08560, which is bordered by GTAGACTTTA and TAAAGTCTAC inverted repeats. Inversion acts as a switch, controlling the tra...
Kalmykov NP.The first data on polymorphism and preadaptation of the Pleistocene horses in the mountains surrounding Lake Baikal are presented. It has been shown that disregard of intraspecific polymorphism leads to unreasonable ignoring of their diversity, phylogenetically false constructions, and incorrect interpretation of natural environment.
Bell K, Arthur H, Breen M.Eleven apparent mutations of the equine plasma transferrin and esterase gene (10 in TF and one in ES) were found in an analysis of approximately 240,000 thoroughbred horses. Eight of the transferrin mutations produced variants not previously recognized in horses. In the two remaining transferrin mutations and the esterase mutation, reduced plasma concentrations of the proteins were demonstrated by immunological techniques and together with the family data indicated the existence of 'null' alleles.
León B, González G, Nicoli A, Rojas A, Pizio AD, Ramirez-Carvajal L, Jimenez C.Venezuelan Equine Encephalitis virus (VEEV) is an arboviral pathogen in tropical America that causes lethal encephalitis in horses and humans. VEEV is classified into six subtypes (I to VI). Subtype I viruses are divided into epizootic (IAB and IC) and endemic strains (ID and IE) that can produce outbreaks or sporadic diseases, respectively. The objective of this study was to reconstruct the phylogeny and the molecular clock of sequences of VEEV subtype I complex and identify mutations within sequences belonging to epizootic or enzootic subtypes focusing on a sequence isolated from a mare in C...
BMC research notesDecember 16, 2009
Volume 2 255 doi: 10.1186/1756-0500-2-255
Rendo F, Iriondo M, Manzano C, Estonba A.The Cantabrian Coast horse breeds of the Iberian Peninsula have mainly black or bay colored coats, but alleles responsible for a chestnut coat color run in these breeds and occasionally, chestnut horses are born. Chestnut coat color is caused by two recessive alleles, e and e(a), of the melanocortin-1 receptor gene, whereas the presence of the dominant, wild-type E allele produces black or bay coat horses. Because black or bay colored coats are considered as the purebred phenotype for most of the breeds from this region, it is important to have a fast and reliable method to detect alleles caus...
de Val N, Herschbach H, Potier N, Dorsselaer AV, Crichton RR.An essential difference between eukaryotic ferritins and bacterioferritins is that the latter contain naturally, in vivo haem as Fe-protoporphyrin IX. This haem is located in a hydrophobic pocket along the 2-fold symmetry axes and is liganded by two Met 52. However, in in vivo studies, a cofactor has been isolated in horse spleen apoferritin similar to protoporphyrin IX; in in vitro experiments, it has been shown that horse spleen apoferritin is able to interact with haem. Studies of haemin (Fe(III)-PPIX) incorporation into horse spleen apoferritin have been carried out, which show that the me...
The Journal of heredityAugust 4, 2021
Volume 112, Issue 5 443-446 doi: 10.1093/jhered/esab037
Hammons V, Ribeiro L, Munyard K, Sadeghi R, Miller D, Antczak D, Brooks SA.Chestnut coat color in horses is determined by a missense mutation within the MC1R gene. However, the intensity of the chestnut color can vary widely within individuals possessing this genotype. Here, we investigated this variation using standardized photographs of 96 horses. Each horse was ranked lightest to darkest within the cohort for phenotype by 3 blinded observers. A genome-wide association study utilizing the relative shade ranking as the phenotype and using 268 487 single-nucleotide polymorphisms (SNPs) genotyped using the Affymetrix Equine 670k array identified a single significantly...
Brandon RB, Giffard JM, Bell K.Single nucleotide polymorphisms (SNPs) in exons 13, 15 and 16 of equine transferrin for common, rare and mutant variants were investigated. Compared with previous work a further 13 SNPs have been identified, allowing for the two previously identified clades to be subdivided into 11 groups. A combination of one or more of eight SNPs can be used to classify the equine variants into these 11 groups, since most are co-inherited. Putative sites of glycosylation in exons 13 and 16 showed no polymorphism, suggesting that presence or absence of sugar moieties does not lead to electrophoretic variation...
Kalemkerian PB, Metz GE, Peral-GarcÃa P, Lopez-Gappa J, EcheverrÃa MG, Giovambattista G, DÃaz S.We investigated the association of equine arteritis virus (EAV) infection and three short tandem repeat (STR) polymorphisms located within or in close proximity to equine lymphocyte antigen (ELA) region. We used a case-control design as a first approach before proceeding to select candidate genes. One hundred and sixty-five Silla Argentino horses were taken in 2002 from positive serological detections of EAV in Argentina, to determine whether STR genotypes were correlated to genetic susceptibility to EVA. Allele frequency distribution did not show significant differences between both groups (P...
van Schalkwyk A, Ferreira ML, Romito M.The outer capsid viral protein 2 (VP2) of African horse sickness virus, encoded by the most variable genome segment 2 (Seg-2), is the primary target for AHSV-specific neutralising antibodies and thus determines the virus serotype. Full length segment 2 sequences from more than 100 AHSVs isolated over the last 80 years were compared and single nucleotide polymorphisms (SNPs) identified between the reference strains and recent field viruses. Regions unique to each individual serotype were identified and primers designed to differentially amplify each of the nine serotypes. The sequences of resul...
Ma Y, Peng S, Donnelly CG, Ghosh S, Miller AD, Woolard K, Finno CJ.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder associated with vitamin E deficiency. In humans, polymorphisms in genes involved in vitamin E uptake and distribution determines individual vitamin E requirements. Objective: Genetic polymorphisms in genes involved in vitamin E metabolism would be associated with an increased risk of eNAD/EDM in Quarter Horses (QHs). Methods: Whole-genome sequencing: eNAD/EDM affected (n = 9, postmortem [PM]-confirmed) and control (n = 32) QHs. Results: eNAD/EDM affected (n = 3...
