A karyotype in horses refers to the complete set of chromosomes present in the cells of a horse, typically organized in a systematic arrangement for analysis. Horses generally have 64 chromosomes, comprising 31 pairs of autosomes and one pair of sex chromosomes. Karyotyping is employed to study chromosomal abnormalities that may affect equine development, fertility, and overall health. It provides insights into genetic disorders, hereditary conditions, and breed-specific traits. This page compiles peer-reviewed research studies and scholarly articles that explore the methodology, findings, and implications of karyotype analysis in equine genetics.
Alizadeh AH, Briah R, Villagomez DAF, King WA, Koch TG.The aim of the present work was to determine proliferation capacity, immunophenotype and genome integrity of mesenchymal stromal cells (MSCs) from horse umbilical cord blood (UCB) at passage stage 5 and 10. Passage 4 cryopreserved UCB-MSCs from six unrelated donors were evaluated. Immunophenotypic analysis of UCB-MSC revealed a cell identity consistent with equine MSC phenotype by high expression of CD90, CD44, CD29, and very low expression of CD4, CD11a/18, CD73, and MHC class I and II antigens. Proliferative differences were noted among the UCB-MSC cultures. UCB-MSCs karyotype characteristic...
Chromosomal abnormalities in the sex chromosome pair (ECAX and ECAY) are widely associated with reproductive problems in horses. However, a large proportion of these abnormalities remains undiagnosed due to the lack of an affordable diagnostic tool that allows for avoiding karyotyping tests. Hereby, we developed an STR (single-tandem-repeat)-based molecular method to determine the presence of the main sex chromosomal abnormalities in horses in a fast, cheap and reliable way. The frequency of five ECAX-linked (LEX026, LEX003, TKY38, TKY270 and UCDEQ502) and two ECAY-linked (EcaYH12 and SRY) mar...
Maia L, Dias MC, de Moraes CN, de Paula Freitas-Dell'Aqua C, da Mota LS, Santiloni V, da Cruz Landim-Alvarenga F.Cryopreservation is a feasible alternative to maintaining several cell lines, particularly for immediate therapeutic use, transportation of samples, and implementation of new in vitro studies. This work parts from the hypothesis that the medium of cryopreservation composed by 90% of conditioned medium (CM) supports cryopreservation of equine umbilical cord intervascular matrix mesenchymal stem cells (UCIM-MSCs), allowing the maintenance of the biological properties for the establishment of cell banks intended for therapeutic use and in vitro studies. Thus, we evaluated the viability, apoptosis...
Dorado J, Anaya G, Bugno-Poniewierska M, Molina A, Mendez-Sanchez A, Ortiz I, Moreno-Millán M, Hidalgo M, Peral García P, Demyda-Peyrás S.Chromosomal abnormalities are one of the main causes of genetic infertility in horses. Currently, their detection rate is rising due to the use of new diagnostic tools employing molecular markers linked to the sex chromosome pair. Despite genetic similarities, there are no previous reports of sterility associated with chromosomal abnormalities in the domestic donkey (Equus asinus). Hereby, we determined the presence of a chromosomal mosaicism in a female donkey with reproductive problems using molecular methodologies developed for horses. A two-and-a-half-year-old jenny characterized by morpho...
Pieńkowska-Schelling A, Handler J, Neuhauser S, Schelling C.The present case report describes a 6-year old subfertile pony mare, which became pregnant after the eleventh artificial insemination. The examination of the ovaries and the uterus did not reveal any abnormal clinical findings and the mare showed a regular oestrous cycle. Based on cytogenetic and molecular genetic analyses it became possible to elucidate the observed subfertility. The mosaic karyotype of the mare consisted of 63,X (20%) and 64,XX (80%) cells. A PCR analysis failed to amplify sequences from the equine SRY gene. The observed classic 63,X/64,XX mosaicism is a plausible explanatio...
Kjöllerström HJ, do Mar Oom M, Chowdhary BP, Raudsepp T.The Sorraia, a critically endangered indigenous Iberian horse breed, is characterized by low genetic variability, high rate of inbreeding, bad sperm quality and subfertility. Here, we studied 11 phenotypically normal but subfertile Sorraia stallions by karyotyping, sex chromosome sperm-FISH and molecular analysis of FKBP6 - a susceptibility locus for impaired acrosome reaction (IAR). The stallions had normal sperm concentration (>300 million cells/ml), but the numbers of progressively motile sperm (21%) and morphologically normal sperm (28%) were invariably low. All stallions had a normal 6...
Raudsepp T, Chowdhary BP.The association between chromosomal abnormalities and reduced fertility in domestic animals is well recorded and has been studied for decades. Chromosome aberrations directly affect meiosis, gametogenesis, and the viability of zygotes and embryos. In some instances, balanced structural rearrangements can be transmitted, causing fertility problems in subsequent generations. Here, we aim to give a comprehensive overview of the current status and future prospects of clinical cytogenetics of animal reproduction by focusing on the advances in molecular cytogenetics during the genomics era. We descr...
Ghosh S, Das PJ, Avila F, Thwaits BK, Chowdhary BP, Raudsepp T.Balanced autosomal translocations are a known cause for repeated early embryonic loss (REEL) in horses. In most cases, carriers of such translocations are phenotypically normal, but the chromosomal aberration negatively affects gametogenesis giving rise to both genetically balanced and unbalanced gametes. The latter, if involved in fertilization, result in REEL, whereas gametes with the balanced form of translocation will pass the defect into next generation. Therefore, in order to reduce the incidence of REEL, identification of translocation carriers is critical. Here, we report about a pheno...
Huang J, Zhao Y, Bai D, Shiraigol W, Li B, Yang L, Wu J, Bao W, Ren X, Jin B, Zhao Q, Li A, Bao S, Bao W, Xing Z, An A, Gao Y, Wei R, Bao Y, Bao T....The donkey, like the horse, is a promising model for exploring karyotypic instability. We report the de novo whole-genome assemblies of the donkey and the Asiatic wild ass. Our results reflect the distinct characteristics of donkeys, including more effective energy metabolism and better immunity than horses. The donkey shows a steady demographic trajectory. We detected abundant satellite sequences in some inactive centromere regions but not in neocentromere regions, while ribosomal RNAs frequently emerged in neocentromere regions but not in the obsolete centromere regions. Expanded miRNA famil...
Dierks C, Sieme H, Piechotta M, Lehner S, Merkt JC, Uphaus H, Klug E, Distl O.A female thoroughbred successful in horse racing was positively tested for high testosterone values. This horse neither showed stallion-like-behaviour nor signs of ambiguous external genitalia. The karyotype of this horse was 2n = 64,XY and the sex-determining region of Y (SRY) PCR was positive. Hair samples tested for naturally testosterone revealed values normal for stallions, and tests for eight synthetic testosterone esters remained negative. The phenotype, ultrasonographic examination, hormone status, cytogenetic evaluation and molecular diagnostics lead to the diagnosis of an XY testicul...
Drbalova J, Musilova P, Kubickova S, Sebestova H, Vahala J, Rubes J.The T cell receptor (TCR) genes (TRA, TRB, TRD and TRG) reside in 3 different chromosomal regions. During the maturation of T lymphocytes, the TCR genes are rearranged by site-specific recombination, a process that also predisposes T cells to aberrant rearrangements. Illegitimate recombination between the TCR genes occurs at a low level in healthy individuals, but this frequency may correlate with the risk of lymphoma. The aim of this work was to investigate interlocus recombination in equids. Illegitimate rearrangements were studied in peripheral blood lymphocytes by FISH with painting and BA...
Nergadze SG, Belloni E, Piras FM, Khoriauli L, Mazzagatti A, Vella F, Bensi M, Vitelli V, Giulotto E, Raimondi E.Centromeres are the sites of kinetochore assembly and spindle fiber attachment and consist of protein-DNA complexes in which the DNA component is typically characterized by the presence of extended arrays of tandem repeats called satellite DNA. Here, we describe the isolation and characterization of a 137-bp-long new satellite DNA sequence from the horse genome (EC137), which is also present, even if less abundant, in the domestic donkey, the Grevy's zebra and the Burchelli's zebra. We investigated the chromosomal distribution of the EC137 sequence in these 4 species. Moreover, we analyzed its...
Anaya G, Moreno-Millán M, Bugno-Poniewierska M, Pawlina K, Membrillo A, Molina A, Demyda-Peyrás S.Horses are characterized as having a greater rate of chromosomal abnormalities than other species, which are mainly related to the sex chromosome pair and produce a series of different anomalies known as disorders in sexual development (DSD). In the present study, three Pura Raza Española (PRE) and one Menorquín (MEN) horses were studied and an incompatibility in their genetic and phenotypic sex were detected. Animals were karyotyped by conventional and molecular cytogenetic analyses and characterized using genomic techniques. Although all individuals, were totally unrelated, these animals h...
Nielsen MK, Wang J, Davis R, Bellaw JL, Lyons ET, Lear TL, Goday C.The equine ascarid parasite Parascaris equorum is well known as a ubiquitous parasite infecting foals. A sibling species, Parascaris univalens, was first described over 130 years ago, but very little attention has been given to its existence and possible implications for anthelmintic resistance, clinical disease, or host age spectrum. P. univalens only possesses one germ line chromosome pair as opposed to two for P. equorum, but the two species are otherwise considered morphologically identical. For the present study, live worms obtained from the University of Kentucky parasitology horse herd ...
Al-Jaru A, Goodwin W, Skidmore J, Raudsepp T, Khazanehdari K.Chromosome configurations and chiasma frequency during the metaphase I stage of spermatogenesis in the male horse are characterized in this work. The genome-wide frequency and distribution of chiasmata was detected as 49.45 ± 2.07 for 14 fertile stallions. All X and Y chromosomes shared a single chiasma at their pseudoautosomal region, while 1-4 chiasmata were observed in autosomal chromosomes. The chiasma frequency and distribution were further studied for 8 different bivalents identified by FISH in 5 fertile stallions. Genetic length was calculated from chiasmata data for the whole genome a...
Pieńkowska-Schelling A, Becker D, Bracher V, Pineroli B, Schelling C.Numerical and structural aberrations of chromosomes may cause malformations, embryonal losses and reduced or missing fertility. In male horses the fertility is rather well controlled through their semen evaluation. For mares there are no mandatory regulations which specify their use in a breeding programme. Therefore, mares with chromosomal aberrations, which exclude reproduction success may be chosen for breeding. The present case describes a horse, offically registered as a female, which was presented for a breeding exam. On this occasion, small and inactive ovaries were diagnosed. Although ...
Huang J, Zhao Y, Shiraigol W, Li B, Bai D, Ye W, Daidiikhuu D, Yang L, Jin B, Zhao Q, Gao Y, Wu J, Bao W, Li A, Zhang Y, Han H, Bai H, Bao Y, Zhao L....Karyotypic diversification is more prominent in Equus species than in other mammals. Here, using next generation sequencing technology, we generated and de novo assembled quality genomes sequences for a male wild horse (Przewalski's horse) and a male domestic horse (Mongolian horse), with about 93-fold and 91-fold coverage, respectively. Portion of Y chromosome from wild horse assemblies (3 M bp) and Mongolian horse (2 M bp) were also sequenced and de novo assembled. We confirmed a Robertsonian translocation event through the wild horse's chromosomes 23 and 24, which contained sequences th...
Whitworth DJ, Ovchinnikov DA, Sun J, Fortuna PR, Wolvetang EJ.In this study we have reprogrammed dermal fibroblasts from an adult female horse into equine induced pluripotent stem cells (equiPSCs). These equiPSCs are dependent only on leukemia inhibitory factor (LIF), placing them in striking contrast to previously derived equiPSCs that have been shown to be co-dependent on both LIF and basic fibroblast growth factor (bFGF). These equiPSCs have a normal karyotype and have been maintained beyond 60 passages. They possess alkaline phosphatase activity and express eqNANOG, eqOCT4, and eqTERT mRNA. Immunocytochemistry confirmed that they produce NANOG, REX1,...
Mercati F, Pascucci L, Curina G, Scocco P, Tardella FM, Dall'aglio C, Marini C, Ceccarelli P.The transplantation of multipotent mesenchymal stromal cells (MSCs) is a potentially promising therapy for the treatment of tendon and ligament injuries and some forms of articular pathology in horses. This study investigated the effects of storage conditions on MSCs. Equine adipose tissue-derived MSCs (eAd-MSCs) were stored at 4 °C and at room temperature (RT) for 24 and 48 h, and viability, doubling time, expression of CD44 and CD90 antigens, clonogenic/differentiation potentials, and karyotype were subsequently evaluated. The eAd-MSC viability was significantly affected by the storage ...
Demyda-Peyrás S, Anaya G, Bugno-Poniewierska M, Pawlina K, Membrillo A, Valera M, Moreno-Millán M.Sex chromosome aberrations are known to cause congenital abnormalities and unexplained infertility in horses. Most of these anomalies remain undiagnosed because of the complexity of the horse karyotype and the lack of specialized laboratories that can perform such diagnoses. On the other hand, the utilization of microsatellite markers is a technique widely spread in horse breeding, mostly because of their usage in parentage tests. We studied the usage of a novel combination of diagnostic approaches in the evaluation of a very uncommon case of chromosomal abnormalities in a Spanish purebred col...
Seltenhammer MH, Sundström E, Meisslitzer-Ruppitsch C, Cejka P, Kosiuk J, Neumüller J, Almeder M, Majdic O, Steinberger P, Losert UM, Stöckl J....The Grey horse phenotype, caused by a 4.6 kb duplication in Syntaxin 17, is strongly associated with high incidence of melanoma. In contrast to most human melanomas with an early onset of metastasis, the Grey horse melanomas have an extended period of benign growth, after which 50% or more eventually undergo progression and may metastasize. In efforts to define changes occurring during Grey horse melanoma progression, we established an in vitro model comprised of two cell lines, HoMel-L1 and HoMel-A1, representing a primary and a metastatic stage of the melanoma, respectively. The cell lines ...
Demyda-Peyrás S, Membrillo A, Bugno-Poniewierska M, Pawlina K, Anaya G, Moreno-Millán M.Chromosomal abnormalities associated to sex chromosomes are reported as a problem more common than believed to be in horses. Most of them remain undiagnosed due to the complexity of the horse karyotype and the lack of interest of breeders and veterinarians in this type of diagnosis. Approximately 10 years ago, the Spanish Purebred Breeders Association implemented a DNA paternity test to evaluate the pedigree of every newborn foal. All candidates who showed abnormal or uncertain results are routinely submitted to cytogenetical analysis to evaluate the presence of chromosomal abnormalities. We s...
Musilova P, Kubickova S, Vahala J, Rubes J.Equidae is a small family which comprises horses, African and Asiatic asses, and zebras. Despite equids having diverged quite recently, their karyotypes underwent rapid evolution which resulted in extensive differences among chromosome complements in respective species. Comparative mapping using whole-chromosome painting probes delineated genome-wide chromosome homologies among extant equids, enabling us to trace chromosome rearrangements that occurred during evolution. In the present study, we performed subchromosomal comparative mapping among seven Equidae species, representing the whole fam...
Maia L, Landim-Alvarenga FC, Da Mota LS, De Assis Golim M, Laufer-Amorim R, De Vita B, Barberini DJ, Listoni AJ, De Moraes CN, Heckler MC, Amorim RM.The aim of this study was to isolate, culture, and characterize mesenchymal stem cells (MSCs) from horse bone marrow (BM) using the techniques of flow cytometry, immunocytochemistry, cytogenetics, and electron microscopy. Immunophenotypic analysis revealed the presence of MSCs with high expression of the CD90 marker, lower expression of the CD44 marker, and absent expression of the CD34 marker. In assays of differentiation, the positive response to osteogenic (OST), chondrogenic (CDG), and adipogenic (ADP) differentiation signals was observed and characterized by deposition of calcium-rich ext...
Holl HM, Lear TL, Nolen-Walston RD, Slack J, Brooks SA.Chromosomal aberrations in the horse are known to cause congenital abnormalities, embryonic loss, and infertility. While diagnosed mainly by karyotyping and FISH in the horse, the use of SNP array comparative genome hybridization (SNP-CGH) is becoming increasingly common in human diagnostics. Normalized probe intensities and allelic ratios are used to detect changes in copy number genome-wide. Two horses with suspected chromosomal abnormalities and six horses with FISH-confirmed aberrant karyotypes were chosen for genotyping on the Equine SNP50 array. Karyotyping of the first horse indicated m...
Torres A, Silva JF, Bernardes N, Sales Luís J, Lopes da Costa L.Here is reported a disorder of sex development found in the Portuguese Lusitano horse breed. The complex genital phenotype included mammary glands, abdominal testes without epididymis, connected through oviducts to pelvic hypoplastic uterine horns and fused vulvar labia majora from which protruded ventrally a penis-like structure. This structure was presented in a reversed position, the urethral opening placed dorsally in the glans. However, it was functional both for micturition and erection. The horse exhibited female micturition posture and aggressive male-like behaviour, including flehmen,...
Sato F, Hirota K, Tozaki T, Ito K, Dhakal P, Taya K, Endo Y, Murase H, Nambo Y.A Thoroughbred colt with ambiguous external genitalia was presented for clinical and histological examinations. The colt had a short penis that faced backward between his hind limbs. The measurements of luteinizing hormone, follicle stimulating hormone, testosterone and ir-inhibin showed a tendency to increase gradually from April. Both the sex-determining region of the Y chromosome and amelogenin gene fragments were detected by the PCR method. A cytogenetic analysis revealed the 63,XO/64,XY mosaic karyotype (ratio 83:17). In autopsy, immature symmetrical subcutaneous testes were found in the ...
Khodadadi K, Sumer H, Pashaiasl M, Lim S, Williamson M, Verma PJ.Despite tremendous efforts on isolation of pluripotent equine embryonic stem (ES) cells, to date there are few reports about successful isolation of ESCs and no report of in vivo differentiation of this important companion species. We report the induction of pluripotency in adult equine fibroblasts via retroviral transduction with three transcription factors using OCT4, SOX2, and KLF4 in the absence of c-MYC. The cell lines were maintained beyond 27 passages (more than 11 months) and characterized. The equine iPS (EiPS) cells stained positive for alkaline phosphatase by histochemical staining ...
Lear TL, McGee RB.Abnormalities of sexual development causing infertility in horses have been investigated since the early 1970's. Conventional cytogenetic analysis by karyotyping has been the primary tool used to investigate these horses. Abnormalities have a broad range, from a phenotypically normal mare with gonadal dysgenesis to a horse with ambiguous external genitalia and internal male and female organs. Cytogenetic analysis can determine genetic sex but cannot identify mutations or deletions of genes involved in the sex determination pathway. Molecular technologies have been developed to confirm cytogene...
Wnuk M, Villagómez DA, Bugno-Poniewierska M, Tumidajewicz P, Carter TF, Slota E.Nucleolar organizing regions (NORs) containing rDNA gene clusters have been assigned to the equine autosomes ECA1, ECA28, and ECA31. Active NORs (Ag-NORs) are associated with argyrophilic proteins, which allow them to be readily identified using silver staining techniques. Fluorescence in situ hybridization (FISH) for rDNA can also be used to visualize all NOR clusters in the nucleus, regardless of whether they are active or inactive. The present study analyzed the distribution and behavior of equine Ag-NOR and NOR clusters in horse spermatozoa and during male meiosis by FISH and silver staini...
Nergadze SG, Belloni E, Piras FM, Khoriauli L, Mazzagatti A, Vella F, Bensi M, Vitelli V, Giulotto E, Raimondi E.Centromeres are the sites of kinetochore assembly and spindle fiber attachment and consist of protein-DNA complexes in which the DNA component is typically characterized by the presence of extended arrays of tandem repeats called satellite DNA. Here, we describe the isolation and characterization of a 137-bp-long new satellite DNA sequence from the horse genome (EC137), which is also present, even if less abundant, in the domestic donkey, the Grevy's zebra and the Burchelli's zebra. We investigated the chromosomal distribution of the EC137 sequence in these 4 species. Moreover, we analyzed its...
Raudsepp T, Kijas J, Godard S, Guérin G, Andersson L, Chowdhary BP.The melanocortin 1 receptor (MC1R), mast/stem cell growth factor receptor (KIT), and platelet-derived growth factor receptor alpha (PDGFRA) are loci that all belong to equine linkage group 2 (LG2). Of these, KIT was fluorescent in situ hybridization (FISH) mapped to ECA3q21 with equine cDNA and heterologous porcine BAC probes, while MC1R was localized to ECA3p12 and PDGFRA to ECA3q21 with heterologous porcine BAC probes. A three-step comparison between ECA3 and donkey chromosomes was carried out. First, microdissected ECA3 painting probe was used on donkey chromosomes, which showed disruption ...
Rambags BP, Krijtenburg PJ, Drie HF, Lazzari G, Galli C, Pearson PL, Colenbrander B, Stout TA.Chromosomal aberrations are often listed as a significant cause of early embryonic death in the mare, despite the absence of any concrete evidence for their involvement. The current study aimed to validate fluorescent in situ hybridization (FISH) probes to label specific equine chromosomes (ECA2 and ECA4) in interphase nuclei and thereby determine whether numerical chromosome abnormalities occur in horse embryos produced either in vivo (n = 22) or in vitro (IVP: n = 20). Overall, 75% of 36,720 and 88% of 2,978 nuclei in the in vivo developed and IVP embryos were analyzable. Using a scoring sys...
Martin F, Svansson V, Eydal M, Oddsdóttir C, Ernback M, Persson I, Tydén E.Horses in Iceland have been isolated for more than 1,000 yr but still harbor a similar range of gastrointestinal parasites as do horses across the world. The long isolation of the horses and their parasites presumably means that no resistance genes have been introduced into the Parascaris spp. population. It is therefore of particular interest to investigate the efficacy of ivermectin on Parascaris spp. infecting Icelandic foals. Potential treatment failure of ivermectin in Iceland will add substantial new information on how resistance can arise independently. This study aimed to determine the...
Blythe LL, Hultgren BD, Craig AM, Appell LH, Lassen ED, Mattson DE, Duffield D.A clinical, viral, hematologic , and genetic study was conducted over a 4-year period on a family of Appaloosas with high incidence of clinical ataxia and pathologic features of equine degenerative myeloencephalopathy. Marginal to deficient serum vitamin E (alpha-tocopherol) and blood selenium values were the only other consistent antemortem abnormalities in the affected horses. Members of this family were all descendants of a clinically normal mare and were raised in 3 separate environments with variable quality of feed. All horses had access to pasture grasses. Normal chromosomal karyotypes ...
Richer CL, Power MM, Klunder LR, McFeely RA, Kent MG.The following decisions concerning the banded karyotype of the horse (Equus caballus) were made at the second International conference for Standardization of Domestic Animal Karyotypes, held at Jouy-en Josas, France, 22nd-26th May 1989: (1) numbering of the chromosomes was modified to correspond to an arrangement into only two groups (the non-acrocentrics and the acrocentrics) within which the autosomes are placed according to length alone; (2) a more compact karyotype arrangement was adopted: chromosomes 1 to 5 on the first row, 6 to 10 on the second, 11 to 13, and, at the far right, X and Y ...
Richard F, Messaoudi C, Lombard M, Dutrillaux B.Using human chromosome painting probes, we looked for homologies between human and mountain zebra (Equus zebra hartmannae, Equidae, Perissodactyla) karyotypes. Except for two very short segments, all euchromatic regions were found to have a human homologous chromosome segment. Conserved syntenies previously described in various mammalian orders were detected. Each synteny corresponded to a chromosomal region homologous to two parts of human chromosomes: HSA3 and HSA21, HSA7 and HSA16, HSA12 and HSA22, and HSA16 and HSA19. Chromosomal segments homologous to a part of HSA11 and HSA19p are found ...
Saito S, Sawai K, Minamihashi A, Ugai H, Murata T, Yokoyama KK.We describe here the isolation and maintenance of pluripotent embryonic stem (ES) cells from equine blastocysts that have been frozen and thawed. Equine ES cells appear to maintain a normal diploid karyotype in culture. These cells express markers that are characteristic of mouse ES cells, namely, alkaline phosphatase, stage-specific-embryonic antigen 1, STAT3, and Oct4. We also describe protocols for the induction of differentiation in vitro to neural precursor cells in the presence of basic fibroblast growth factor (bFGF), epidermal growth factor, and platelet-derived growth factor and to he...
Bugno M, Słota E, Kościelny M.Five hundred young horses of the following breeds: Thoroughbred, Silesian, Malopolska, Wielkopolska, Polish Konik, Hutsul, Shetland Pony, Half-bred Anglo-Arabian, Noble Half-bred, Fjord and crosses were cytogenetically investigated. Chromosome preparations obtained after lymphocyte culture were analysed using conventional Giemsa staining and CBG-banding methods. In the case of abnormalities GTG-banding as well as FISH technique were applied. In ten mares different karyotypic abnormalities were diagnosed. One mare showed chromosome chimerism (64,XX/64,XY), eight had sex chromosomal aneuploidy (...
Lear TL, Bailey E.Cytogenetic analyses of horses have benefited the horse industry by identifying chromosomal aberrations causing congenital abnormalities, embryonic loss and infertility. Technical advances in cytogenetics enabled the identification of chromosome specific aberrations. More recently, advances in genomic tools have been used to more precisely define chromosome abnormalities. In this report we review the history of equine clinical cytogenetics, identify historical landmarks for equine clinical cytogenetics, discuss how the current use of genomic tools has benefited this area, and how future genomi...
Lear TL, McGee RB.Abnormalities of sexual development causing infertility in horses have been investigated since the early 1970's. Conventional cytogenetic analysis by karyotyping has been the primary tool used to investigate these horses. Abnormalities have a broad range, from a phenotypically normal mare with gonadal dysgenesis to a horse with ambiguous external genitalia and internal male and female organs. Cytogenetic analysis can determine genetic sex but cannot identify mutations or deletions of genes involved in the sex determination pathway. Molecular technologies have been developed to confirm cytogene...
Chaudhary R, Raudsepp T, Guan XY, Zhang H, Chowdhary BP.Microdissected arm specific paints (ASPs) for human (HSA) chromosomes (Chrs) 2, 5, 6, 16, and 19 were used as probes on pig (SSC) and horse (ECA) metaphase chromosomes. Regions homologous to individual human arms were delineated in the two species studied. Of the ten ASPs used, HSA6 and 16 ASPs showed complete synteny conservation of individual arms as single blocks/ arms both in pig and horse. A similar trend was, in general, also observed for HSA19 ASPs. However, contrary to these observations, synteny conservation of individual arms of HSA2 and HSA5 was not observed in pig and horse. The ar...
Godard S, Schibler L, Oustry A, Cribiu EP, Guérin G.A horse BAC library was constructed with about 40,000 clones and mean insert size of 110 kb representing a 1.5 genome equivalent coverage and a probability of finding a single sequence of 0.75. It was characterized by PCR screening of about 130 sequences of horse microsatellites and exonic gene sequences retrieved from databases. BACs containing 8 microsatellites and 12 genes were subsequently localized by fluorescent in situ hybridization (FISH) on chromosomes. Two linkage groups were newly assigned to chromosomes: LG2 to ECA3 and LG5 to ECA24, and five linkage groups were also oriented--LG3,...
Raudsepp T, Lear TL, Chowdhary BP.The X chromosomes of the extant equids, in general, share morphology and banding pattern similarities. However, the donkey X is, in part, an exception because of significantly different centromeric index and variant banding patterns in the pericentromeric region. To verify the underlying molecular basis of this difference, twelve equine BAC clones were FISH mapped to donkey (EAS) and Hartmann's mountain zebra (EZH) metaphase spreads. Loci from the terminal region of Xp and distal to terminal regions of the Xq showed the same order and relative position in all three species, implying cross-spec...
Maia L, Landim-Alvarenga FC, Da Mota LS, De Assis Golim M, Laufer-Amorim R, De Vita B, Barberini DJ, Listoni AJ, De Moraes CN, Heckler MC, Amorim RM.The aim of this study was to isolate, culture, and characterize mesenchymal stem cells (MSCs) from horse bone marrow (BM) using the techniques of flow cytometry, immunocytochemistry, cytogenetics, and electron microscopy. Immunophenotypic analysis revealed the presence of MSCs with high expression of the CD90 marker, lower expression of the CD44 marker, and absent expression of the CD34 marker. In assays of differentiation, the positive response to osteogenic (OST), chondrogenic (CDG), and adipogenic (ADP) differentiation signals was observed and characterized by deposition of calcium-rich ext...
Rønne M.After fluorouracil/5-bromodeoxyuridine synchronization and subsequent FPG-staining, the karyotype of 15 phenotypically normal horses displayed several breaks and gaps. Twelve bands 1q24, 4p12, 8q23, 11p12, 16q21, 17q21, 23q31, 23q32, Xp21, Xq22, Xq25 and Xq27 showed relatively frequent fragility. After thymidine/cytidine synchronization and subsequent GWL-banding the same horses display karyotypes without any fragility. Hence it is suggested that the above listed bands harbour folate and/or 5-bromodeoxyuridine sensitive fragile sites.
Zong E, Fan G.Generally speaking, the majority of F1 hybrids between the horse and donkey are sterile and do conform to the hypothesis of gametogenic breakdown. The results of our own research, nevertheless, lead us to conclude that there is variability in degree of sterility and fertility for both F1 and B1 individuals, with a gradual advance from sterility to fertility being seen. This is the subject we will discuss from the point of view of oestrus, ovulation, mating, pregnancy, spermatogenesis, endocrine activity, isozymes and karyotypic analysis in this paper.
Oakenfull EA, Buckle VJ, Clegg JB.The alpha-globin gene complex in Equus caballus has been mapped by fluorescence in situ hybridization to the telomeric region of the long arm of chromosome 13. This is the first equine gene to be mapped to this chromosome.
Demyda-Peyrás S, Anaya G, Bugno-Poniewierska M, Pawlina K, Membrillo A, Valera M, Moreno-Millán M.Sex chromosome aberrations are known to cause congenital abnormalities and unexplained infertility in horses. Most of these anomalies remain undiagnosed because of the complexity of the horse karyotype and the lack of specialized laboratories that can perform such diagnoses. On the other hand, the utilization of microsatellite markers is a technique widely spread in horse breeding, mostly because of their usage in parentage tests. We studied the usage of a novel combination of diagnostic approaches in the evaluation of a very uncommon case of chromosomal abnormalities in a Spanish purebred col...
Bugno-Poniewierska M, Raudsepp T.Clinical cytogenetic studies in horses have been ongoing for over half a century and clearly demonstrate that chromosomal disorders are among the most common non-infectious causes of decreased fertility, infertility, and congenital defects. Large-scale cytogenetic surveys show that almost 30% of horses with reproductive or developmental problems have chromosome aberrations, whereas abnormal karyotypes are found in only 2-5% of the general population. Among the many chromosome abnormalities reported in the horse, most are unique or rare. However, all surveys agree that there are two recurrent c...
Bowling AT, Millon LV.The phenotypic effects in a yearling Arab filly of a newly described equine autosomal trisomy syndrome for chromosome 30 (65,XX,+30) consisted of small size and severe angular deviation of front legs accompanied by mild polydactyly, but no mental dullness. This case was associated with advanced maternal age. Additional banding studies of a second trisomy case confirmed the assignment to chromosome 26 (64,XX,-26,+t(26q26q)) and evidence of her fertility was presented.
Chandley AC, Fletcher J, Rossdale PD, Peace CK, Ricketts SW, McEnery RJ, Thorne JP, Short RV, Allen WR.Chromosomal abnormalities have been detected in seven mares isolated by their poor reproductive performance. All had small or rudimentary gonads and absent or irregular oestrous cycles. Two mares had an XO genotype, one was a 65,XXX female and another a 64,XY sex-reversed female. Two other mares were sex chromosome mosaics of the 63,X/64,XX type. The seventh mare showed a normal female karyotype but a small extra autosomal fragment was found in a few cells.
Myka JL, Lear TL, Houck ML, Ryder OA, Bailey E.The genus Equus is unusual in that five of the ten extant species have documented centric fission (Robertsonian translocation) polymorphisms within their populations, namely E. hemionus onager, E. hemionus kulan, E. kiang, E. africanus somaliensis, and E. quagga burchelli. Here we report evidence that the polymorphism involves the same homologous chromosome segments in each species, and that these chromosome segments have homology to human chromosome 4 (HSA4). Bacterial artificial chromosome clones containing equine genes SMARCA5 (ECA2q21 homologue to HSA4q31. 21) and UCHL1 (ECA3q22 homologue ...
Pirosanto Y, Laseca N, Valera M, Molina A, Moreno-Millán M, Bugno-Poniewierska M, Ross P, Azor P, Demyda-Peyrás S.Chromosomal abnormalities are a common cause of infertility in horses. However, they are difficult to detect using automated methods. Here, we propose a simple methodology based on single nucleotide polymorphism (SNP)-array data that allows us to detect the main chromosomal abnormalities in horses in a single procedure. As proof of concept, we were able to detect chromosomal abnormalities in 33 out of 268 individuals, including monosomies, chimerisms, and male and female sex-reversions, by analyzing the raw signal intensity produced by an SNP array-based genotyping platform. We also demonstrat...
Ciotola F, Albarella S, Pasolini MP, Auletta L, Esposito L, Iannuzzi L, Peretti V.An 18-month-old Arabian foal characterized by a stallion-like appearance was submitted for cytogenetic and molecular genetics examinations due to abnormalities of external genitalia and the presence of ovotestis-like structures in the abdominal cavity. By RB-banding the animal showed the normal female equine karyotype (2n = 64,XX). Molecular analysis revealed the absence of the SRY and ZFY genes and the presence of ZFX, a typical female equine condition. The entire RSPO1 coding region was examined to exclude its involvement. Although a SNP was found in exon 3, it was not responsible for an ami...
