Equids are members of the family Equidae, which includes modern horses, donkeys, and zebras, as well as extinct species. Equids are characterized by their long limbs, single-toed hooves, and herbivorous diet, which is primarily composed of grasses. Horses, specifically, have been domesticated for thousands of years and have played significant roles in agriculture, transportation, and sport. This page compiles peer-reviewed research studies and scholarly articles that explore various aspects of equids and horses, including their evolution, physiology, behavior, and interactions with humans. The collected works provide insights into the genetic diversity, adaptive traits, and conservation efforts related to equid species.
Story MR, Nout-Lomas YS.Recognizing possible causes of equine head and neck problems requires a careful and systematic evaluation. While for some disorders reaching a diagnosis and treatment plan is relatively straightforward, for others this can be a complicated road requiring extensive diagnostic techniques, treatment trials, and management strategies. The ability to determine whether the patient is in a painful state, experiencing functional deficits, or in a combination of pain and dysfunction is critical to developing an effective treatment plan. Frequently, behavioral concerns often associated with pain must be...
Zullo KV, Davis JG, Bubeck K.To demonstrate the uses, data interpretation, and limitations of objective gait analysis methods in equine practice. Unassigned: Teaching and client-owned horses. Unassigned: Informed owner consent was obtained for all animals used in the making of this technical tutorial video. Primary literature relevant to this video was reviewed from January 2016 to January 2026. Images and data were collected from teaching horses and client-owned horses. Unassigned: Objective gait analysis provides accurate and repeatable data on the locomotion of a horse; however, inaccuracies may occur, especially in ca...
Rivers S, Robertson G, O'Sullivan L, Powell T, Porr S.Serum cortisol concentration is one of the common physiological reference standards for evaluating stress in animals. However, it only evaluates acute stress at the moment of blood collection. Hair cortisol concentrations (HCC) could provide a method for assessing cortisol concentrations over extended periods of time, giving an estimate of chronic stress levels. In this case, high HCC results could help equine managers alter management practices to improve welfare. Objective: To evaluate the effect of the month of collection and the storage method on equine HCC. Methods: Tail hair was collecte...
Gluck-Flynn CR, Han H, Valenzuela M, Routh P, Ostland VE, Pratt-Phillips SE.Hepcidin (Hepc) is a peptide hormone primarily produced by hepatocytes and considered the master regulator of iron homeostasis, with Hepc controlling the release of iron within the circulation. Despite the renewed interest in iron-related research due to Hepc discovery, there is limited data on serum hepcidin in horses. The objective of the study was to develop and partially validate a competitive enzyme-linked immunosorbent assay (ELISA) to quantify serum hepcidin in horses. Precision was evaluated using horse serum samples representing low, medium and high Hepc concentrations, yielding intra...
Ehizibolo DO, Oyekan O, Mkpuma N, Haliru H, Garba I, Turaki IZ, Kennedy S, Shallangwa JM, Kilyobas CS, Mohammed A, Muhammad MA, Abubakar M....Crimean-Congo haemorrhagic fever virus (CCHFV) is a tick-borne zoonotic pathogen of major public health importance in Africa. Although CCHFV exposure has been reported in several livestock species in Nigeria, data on equids remain limited despite their extensive involvement in livestock movement and trade. This study assessed CCHFV seroprevalence in horses and donkeys in major international livestock markets in northern Nigeria and examined factors associated with exposure. Methods: From June 2023 to July 2024, a longitudinal sero-surveillance study was conducted in three high-volume livestock...
Bostick HN, Keys DA, Bowden AC, McMullen RJ.To compare equine optic nerve head (ONH) measurements using spectral domain optical coherence tomography (SD-OCT) to detect clinically relevant ONH cupping. Methods: Forty-five eyes from 34 horses were categorized as CONTROL or CUPPED based on indirect ophthalmoscopy and were measured using SD-OCT: Bruch's membrane opening (BMO), optic cup width (OC), anterior laminar depth (ALD), prelaminar thickness (PLT), and cup-to-disk ratio (OC: BMO) at superior (sup.), central (ctr.), and inferior (inf.) ONH locations. Results: The OC:BMO was 0.61 ± 0.09 (sup.), 0.64 ± 0.09 (ctr.), and 0.55 ...
Ropka-Molik K, Musiał AD, Majtyka A, Bieniek A, Ayad A, Muszyński S, Stefaniuk-Szmukier M.The DMRT3 gene, often referred to as the "gait keeper," plays a key role in controlling alternative gaits in horses, such as tölt and pace. This study aimed to determine the frequency of known and to screen for potential novel polymorphisms within the second exon of the DMRT3 gene. Methods: A total of 244 blood or hair samples were collected from representative individuals of the six horse breeds: gaited (Icelandic Horse, French Trotter), non-gaited (Arabian Horse, Malopolski Horse), and pony breeds (Welsh Pony, Shetland Pony). Methods: The second exon of the DMRT3 gene analyzed using Sanger ...
Campilho R, Saraiva S, Chaves S, Quaresma M, Silva F, Pires I.An 8-month-old Lusitano filly (a young female horse) was referred with a five-day history of abdominal distension, respiratory distress, and hyporexia. Clinical and ultrasonographic examinations revealed ventral edema, anemia, leukocytosis, hypoalbuminemia, and bilateral pleural effusion. The filly subsequently developed progressive clinical deterioration, including persistent hyporexia, scant fecal output, and acute colic with nasogastric reflux, followed by sudden respiratory decompensation, collapse, and death. Post-mortem examination revealed a large, multilobulated abdominal mass involvin...
Manso-Díaz G.Diagnostic imaging is essential for evaluating and managing neurologic disease in horses. Following clinical lesion, neurolocalization imaging modalities are often necessary to further characterize the disease process. However, which technology to use depends on various factors, including the patient's size, clinical signs, and the anatomic region. Current advances in imaging technology, in general, and the adaptation of different modalities for equine patients, in particular, have substantially improved our ability to evaluate the equine central nervous system. This article will summarize the...
Yang X, Wen L, Wen M, Yao X, Meng J, Zeng Y, Ren W.Equus caballus is a species of considerable economic and cultural significance. However, the regulatory networks involved in equine sexual maturation remain unclear and eventually limit its reproduction and utilization. In this study, testicular tissues from eight Kazakh horses at two developmental stages (2 years, representing pre-maturation, and 3 years, representing post-maturation) were analyzed using whole transcriptome sequencing, data-independent acquisition (DIA) proteomics, and untargeted metabolomics. An integrated regulatory network was constructed encompassing ceRNA, mRNA, prot...
Soni S, Eertink LG, Shuisong N, Loynachan A, Barnum SM, Adam EN, Kennedy MA, Wang D, Li F.Rotaviral diarrhea in foals is caused by two dominant G3P[12] and G14P[12] genotypes of equine rotavirus A (ERVA). Protection of foals against ERVA infection and disease is achievable by passive antibody transfer through colostrum from mares receiving inactivated monovalent G3P[12] vaccine. Simian rotavirus SA11 G3P[2] is also included in ERVA vaccines to protect foals. Here, we characterized cross-neutralization and protection among three distinctive rotaviruses carrying the same or different G (defined by VP7) or P (defined by VP4) genotype by using a rabbit and equine monospecific antisera ...
Gmel AI, Pirani A, McInnis L, Neuditschko M.Single nucleotide polymorphism (SNP) arrays are commonly used in livestock genetics to investigate complex traits including genome-wide associations and fine mapping, genomic prediction and genetic diversity analyses. In a European equine diversity study, we analysed the AxiomTM Equine 670K SNP genotype data from 2,768 equids representing 20 horse breeds and one donkey breed. Using a strict detection setting to identify genome-wide runs of homozygosity (ROH), 169 purebred horses displayed fewer ROH segments than F1 crosses. Under medium and relaxed settings, ROH counts increased, while some ho...
Firdausy LW, Fikri F, Wicaksono AP, Maslamama ST, Purnama MTE.Equine viral arteritis (EVA) is a globally widespread infectious disease affecting equids, with significant consequences for reproductive efficiency and the regulation of international equine trade. Nevertheless, despite the accumulation of numerous region-specific investigations, an integrated synthesis of global seroprevalence estimates and overarching epidemiological patterns remains insufficiently developed. Objective: To calculate the pooled global seroprevalence of EVA and to explore sources of epidemiological heterogeneity. Methods: A systematic review and meta-analysis were undertaken ...
Papas M, Stout TAE, Vernooij JCM, Leemans B, Arnold L, Beitsma MM, Wijnands LI, de Ruijter-Villani M, Colleoni S, Lazzari G, Galli C, Claes A.The success of in vitro embryo production (IVEP) is influenced by donor mare and stallion. Objective: To determine whether donor mare and stallion influence the pregnancy rate after transfer of in vitro produced (IVP) blastocysts and to identify factors influencing the likelihood of obtaining one or more pregnancies from a single IVEP session. Methods: Retrospective clinical study. Methods: The influence of the following variables on pregnancy outcome was assessed in 2292 transfers of IVP blastocysts: speed of in vitro embryo development, embryo grade after thawing, age of the donor mare, blas...
Al Aiyan A, Alnahdi AF, Abu Hayah S, Alshamsi A, Alshebli H, Aleissaee S, Balan R.The cerebral blood supply in horses is maintained by carotid and vertebrobasilar systems, which join the cerebral arterial circle to ensure continuous brain perfusion. This study aimed to comprehensively describe the origins, courses, and interconnections of the vertebrobasilar and carotid systems in the horse brain. Unassigned: Ten adult equine specimens were obtained from horses euthanized for non-neurological reasons. Following perfusion with 10% formaldehyde, colored latex was injected into the arterial system, and detailed dissections were performed to study major intracranial vessels. Un...
Crowell CN, Handlos GC, Discepolo DR, Roeder M, Perry EB.Palatability research in horses has primarily been conducted in mature, non-lactating horses and has typically investigated gustatory rather than aromatic preference. Objective: The objective of this study was to investigate the gustatory and aromatic preferences of nursing foals. Methods: Stock-type mare (13.25 ± 4.40 years) and foal (6 ± 3 weeks) pairings (n = 4) were utilized in multi-preference testing for treatments including apple, anise, peppermint and control (no palatant). Mares and foals were placed in assigned split stalls for 1800 seconds and provided unrestricted access to a...
Błaszczak A, Olczak K, Stefaniuk-Szmukier M, Tomczyk-Wrona I, Musiał AD, Grzegorczyk J, Długosz B, Szmatoła T, Ropka-Molik K.Insect bite hypersensitivity (IBH) is a prevalent allergic skin disease in horses that significantly affects animal welfare and shows evidence of genetic predisposition. Objective: Understanding the genetic basis of IBH can improve management and breeding strategies. The Equine80K BeadChip microarray was used to identify genomic regions associated with the occurrence of IBH in Hucul horses. Methods: Hair samples were collected from 127 Hucul horses, including both affected individuals and controls. DNA was extracted and genotyped. A genome-wide association study (GWAS) was performed to identif...
Duarte FRSC, Lima FR, Medeiros GC, Furtado LL, Aquino LPCT, Fonteque JH, Moura AB, Chryssafidis AL.Werneckiella equi is an ectoparasite of equids, and control can be challenging because of the limited availability of licensed products. This case report describes the clinical observation of 1% fipronil pour-on against W. equi infestation in horses admitted to a veterinary hospital. Two horses were treated and observed between 2022 and 2023. Both exhibited pruritus, especially in the head, withers, and croup regions, and were diagnosed with severe W. equi infestation. The treatment consisted of a single topical application of 1% fipronil pour-on (1 mg/kg). Parasite reduction was assessed by c...
Souza MG, Mota Melo L, Martinez RE, Teague SR, Beck RL.In vitro fertilization (IVF) in horses has emerged as a valuable assisted reproductive technology, yet the impact of embryo cryopreservation on pregnancy outcomes when utilizing this technique remains unclear. This study reports pregnancy outcomes following transfer of conventional equine IVF embryos, with both fresh and vitrified-warmed embryos. Conventional IVF (cIVF) was used to produce 40 embryos, which were transferred to recipient mares, pregnancy diagnosis was performed at 6 days post-transfer followed by embryonic heartbeat detection between day 25 and 30 of gestation. Observed pregnan...
Szara T, Hadžiomerović N, Bakıcı C, Güzel BC, Gündemir O, Gündemir O.Three-dimensional geometric morphometric methods have emerged as a pivotal tool in veterinary anatomy, taxonomy, clinical research, and studies of morphological diversity. This article summarizes the key stages, applications, clinical potential, and recommendations for data standardization in 3D morphometrics. Datasets are typically acquired using radiological modalities, including computed tomography (CT), magnetic resonance imaging (MRI), and 3D surface scanning, each offering specific advantages and constraints contingent on the research context. Standardized landmark sets are essential in ...
Kovács BA, Topál J, Gergely A.The relationship between horses and humans is often described as cooperative and affective, yet empirical studies on horse-rider bond remain scarce. Previous findings on horse-human relationships yielded conflicting results on whether and how horses show bonding like behaviour toward their owners. Objective: We tested whether horses show partner-specific approach and proximity toward their primary rider compared with an unfamiliar experimenter in an adapted Strange Situation Test, and whether the rider's presence was associated with behavioural patterns indicative of safe haven and secure base...
Mackowski M, Kajdasz A, Laskowska K, Cieslak J.Although serological and genetic studies of equine blood group systems have been conducted for many years, the molecular basis of erythrocyte antigens' variability has remained largely unexplored. In this study, we aimed to elucidate the genetic basis of serological variation within equine blood group K. Using mRNA extracted from peripheral blood samples (n = 100) collected from horses with known serological blood types (Ka or K-), we performed a transcriptome-wide association study (TWAS), which revealed a significantly associated region on equine chromosome 2 (ECA2). A detailed analysis ...
Basher AA, Ahmed AA, Pfukenyi DM, Liu HY, Essa MOA, Husien HM, Saleh AA, Adam SY, Cai D.Assessing the welfare of the working horses is crucial for identifying health and management issues and implementing effective solutions. This study evaluated the welfare of working horses in South Darfur, Sudan, by integrating clinical examination with indirect indicators through owner interviews. A total of 400 horse-owner pairs were included. Most horses (61.7%) worked every day, and 77% of owners reported using whips to encourage movement. Clinical assessment revealed that 29.0% of horses were thin, over half had dirty coats, 50.5% harbored external parasites, 43% had abnormal discharges, ...
Latorre N, Gómez-Cuétara C, Cañizares E, Crespo F, Pérez-Aguilera V, Cuerda MI, Laborda-Gomariz JA, Soler AJ, Roldan ERS, Sanchez-Rodriguez A.Evaluating semen quality in Purebred Spanish Horses is essential to determine reproductive potential and optimize assisted reproductive techniques. Objective: This study compared several sperm analysis methods in Purebred Spanish Horses to standardize protocols suitable for both laboratory and field conditions. Methods: Fifteen stallions were evaluated through three ejaculates, analyzing sperm parameters using different techniques. Sperm kinematics was assessed by Sperm Computer Analyzer (SCA-CASA) or iSperm mCASA. Viability was analyzed by eosin-nigrosin-Giemsa (ENG) staining or Hoechst 33258...
Loosley H, Rehbein LS, Lima EMM, Blake R.Elevated pressures beneath training rollers during the Pessoa training aid (PTA) use have been reported, particularly over the thoracic region, which may contribute to back discomfort. Objective: To investigate the effect of different pads on pressures and forces beneath a training roller during lunging with a PTA. Methods: Six clinically sound horses (13.8 ± 5.2 years) were lunged on a 16-m circle in trot and canter using a randomised crossover design under three conditions: no padding (Pad 1), a folded cotton saddle cloth (Pad 2), and a purpose-made roller foam pad (Pad 3). Kinetic data wer...
Masuda M, Tozaki T, Kawate K, Furukawa R, Kikuchi M, Ishige T, Kakoi H.The Miyako horse is one of the eight Japanese native horse breeds and is scarce in terms of population size. Japanese native horses are believed to be descended from Mongolian horses and represent a precious lineage that has preserved its traits for over a thousand years in Japan. Genetic analysis of the endangered Miyako horse is useful for preserving its original phenotypic traits. This study analysed the genetic variation in trait-related genes for coat colour (), body composition (), gait (), and temperament () in 46 extant Miyako horses. In addition, because numerous Miyako horses have ve...
Akinniyi OO, Afolabi DO, Mshelia PW, Olakojo TA, Oyenekan IO, Adah O, Osunkoya D, Olaogun SC, Jeremiah OT, Omobowale TO.Dental age estimation in horses is very important in the context of quality healthcare, breeding programs, and welfare management. However, information on the most suitable dental age estimation methods for Nigerian local horses is not available in the literature. We evaluated and compared dental age estimates based on six dental age estimation methods with known chronological ages of Nigerian local horses to establish the most accurate techniques for this population. A cross-sectional study of 180 Nigerian local horses was conducted in Ibadan, Nigeria. Six dental age estimation methods (erupt...
Bindi F, Vitale V, Cingottini D, Pasquini A, Longini M, Tagliaferri G, Bonelli F, Nocera I, Sgorbini M.Equine asthma is a common chronic respiratory disease characterized by airway inflammation and oxidative imbalance, particularly in its severe form. The aim of this study was to evaluate pro-oxidative substances, oxidative products, and antioxidant defense biomarkers in bronchoalveolar lavage fluid (BALF) from horses with and without a history of severe equine asthma (SEA). This prospective observational study included 21 leisure horses classified as SEA or non-SEA based on clinical history and BALF cytology. Bronchoalveolar lavage fluid was analyzed for derivatives of reactive oxygen metaboli...
Elsawy BSM, Alzan HF., a recently discovered tick-borne hemoparasite infecting equids globally, has significant implications for equine health. Although it is closely related to (sharing 23% genomic divergence), it establishes an asymptomatic carrier state in persistently infected horses, creating a silent transmission reservoir. Its discovery and unique genetics justify its classification as a new taxon. A critical diagnostic challenge is that the lack of the gene in prevents its detection by the standard cELISA, emphasizing the need for species-specific tools. Although species-specific PCR assays, including ...
Hansen TF.Comparative studies tend to differ from optimality and functionality studies in how they treat adaptation. While the comparative approach focuses on the origin and change of traits, optimality studies assume that adaptations are maintained at an optimum by stabilizing selection. This paper presents a model of adaptive evolution on a macroevolutionary time scale that includes the maintenance of traits at adaptive optima by stabilizing selection as the dominant evolutionary force. Interspecific variation is treated as variation in the position of adaptive optima. The model illustrates how phylog...
Cameron EZ, Setsaas TH, Linklater WL.In many mammals, females form close social bonds with members of their group, usually between kin. Studies of social bonds and their fitness benefits have not been investigated outside primates, and are confounded by the relatedness between individuals in primate groups. Bonds may arise from kin selection and inclusive fitness rather than through direct benefits of association. However, female equids live in long-term social groups with unrelated members. We present 4 years of behavioral data, which demonstrate that social integration between unrelated females increases both foal birth rates a...
Science (New York, N.Y.)May 9, 2018
Volume 360, Issue 6396 eaar7711 doi: 10.1126/science.aar7711
de Barros Damgaard P, Martiniano R, Kamm J, Moreno-Mayar JV, Kroonen G, Peyrot M, Barjamovic G, Rasmussen S, Zacho C, Baimukhanov N, Zaibert V....The Yamnaya expansions from the western steppe into Europe and Asia during the Early Bronze Age (~3000 BCE) are believed to have brought with them Indo-European languages and possibly horse husbandry. We analyzed 74 ancient whole-genome sequences from across Inner Asia and Anatolia and show that the Botai people associated with the earliest horse husbandry derived from a hunter-gatherer population deeply diverged from the Yamnaya. Our results also suggest distinct migrations bringing West Eurasian ancestry into South Asia before and after, but not at the time of, Yamnaya culture. We find no ev...
Seluanov A, Gladyshev VN, Vijg J, Gorbunova V.Cancer researchers have traditionally used the mouse and the rat as staple model organisms. These animals are very short-lived, reproduce rapidly and are highly prone to cancer. They have been very useful for modelling some human cancer types and testing experimental treatments; however, these cancer-prone species offer little for understanding the mechanisms of cancer resistance. Recent technological advances have expanded bestiary research to non-standard model organisms that possess unique traits of very high value to humans, such as cancer resistance and longevity. In recent years, several...
Dubey JP, Desmonts G.SEROLOGICAL and parasitological surveys indicate that Toxoplasma gondii infection is widely prevalent in horses (Riemann et a! 1975). To study the pathogenesis of orally-induced toxoplasmosis, 13 equids aged between Aix months and 13 years (nine ponies, three horses and one mule) were each inoculated orally with 10,000 oocysts of the GT-I strain of TRondii. The equids were killed 33 to 476 days after inoculation and their tissues were bioassaycd for T gondit (Dubey 1985). Details of inoculation, housing, clinical response and parasitological and histological findings were previously reported (...
Higuchi R, Bowman B, Freiberger M, Ryder OA, Wilson AC.To determine whether DNA survives and can be recovered from the remains of extinct creatures, we have examined dried muscle from a museum specimen of the quagga, a zebra-like species (Equus quagga) that became extinct in 1883 (ref. 1). We report that DNA was extracted from this tissue in amounts approaching 1% of that expected from fresh muscle, and that the DNA was of relatively low molecular weight. Among the many clones obtained from the quagga DNA, two containing pieces of mitochondrial DNA (mtDNA) were sequenced. These sequences, comprising 229 nucleotide pairs, differ by 12 base substitu...
Science (New York, N.Y.)March 7, 2009
Volume 323, Issue 5919 1332-1335 doi: 10.1126/science.1168594
Outram AK, Stear NA, Bendrey R, Olsen S, Kasparov A, Zaibert V, Thorpe N, Evershed RP.Horse domestication revolutionized transport, communications, and warfare in prehistory, yet the identification of early domestication processes has been problematic. Here, we present three independent lines of evidence demonstrating domestication in the Eneolithic Botai Culture of Kazakhstan, dating to about 3500 B.C.E. Metrical analysis of horse metacarpals shows that Botai horses resemble Bronze Age domestic horses rather than Paleolithic wild horses from the same region. Pathological characteristics indicate that some Botai horses were bridled, perhaps ridden. Organic residue analysis, usi...
Science (New York, N.Y.)February 13, 2001
Volume 291, Issue 5503 474-477 doi: 10.1126/science.291.5503.474
Vilà C, Leonard JA, Gotherstrom A, Marklund S, Sandberg K, Liden K, Wayne RK, Ellegren H.Domestication entails control of wild species and is generally regarded as a complex process confined to a restricted area and culture. Previous DNA sequence analyses of several domestic species have suggested only a limited number of origination events. We analyzed mitochondrial DNA (mtDNA) control region sequences of 191 domestic horses and found a high diversity of matrilines. Sequence analysis of equids from archaeological sites and late Pleistocene deposits showed that this diversity was not due to an accelerated mutation rate or an ancient domestication event. Consequently, high mtDNA se...
Frantz LAF, Bradley DG, Larson G, Orlando L.The domestication of animals led to a major shift in human subsistence patterns, from a hunter-gatherer to a sedentary agricultural lifestyle, which ultimately resulted in the development of complex societies. Over the past 15,000 years, the phenotype and genotype of multiple animal species, such as dogs, pigs, sheep, goats, cattle and horses, have been substantially altered during their adaptation to the human niche. Recent methodological innovations, such as improved ancient DNA extraction methods and next-generation sequencing, have enabled the sequencing of whole ancient genomes. These gen...
Librado P, Khan N, Fages A, Kusliy MA, Suchan T, Tonasso-Calvière L, Schiavinato S, Alioglu D, Fromentier A, Perdereau A, Aury JM, Gaunitz C....Domestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 BC. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don regi...
Ludwig A, Pruvost M, Reissmann M, Benecke N, Brockmann GA, Castaños P, Cieslak M, Lippold S, Llorente L, Malaspinas AS, Slatkin M, Hofreiter M.The transformation of wild animals into domestic ones available for human nutrition was a key prerequisite for modern human societies. However, no other domestic species has had such a substantial impact on the warfare, transportation, and communication capabilities of human societies as the horse. Here, we show that the analysis of ancient DNA targeting nuclear genes responsible for coat coloration allows us to shed light on the timing and place of horse domestication. We conclude that it is unlikely that horse domestication substantially predates the occurrence of coat color variation, which...
Jónsson H, Schubert M, Seguin-Orlando A, Ginolhac A, Petersen L, Fumagalli M, Albrechtsen A, Petersen B, Korneliussen TS, Vilstrup JT, Lear T....Horses, asses, and zebras belong to a single genus, Equus, which emerged 4.0-4.5 Mya. Although the equine fossil record represents a textbook example of evolution, the succession of events that gave rise to the diversity of species existing today remains unclear. Here we present six genomes from each living species of asses and zebras. This completes the set of genomes available for all extant species in the genus, which was hitherto represented only by the horse and the domestic donkey. In addition, we used a museum specimen to characterize the genome of the quagga zebra, which was driven to ...
Xu X, Arnason U.The sequence of the mitochondrial (mt) DNA of the horse (Equus caballus) was determined. The length of the sequence presented is 16,660 bp. This figure, however, is not absolute due to pronounced heteroplasmy caused by variable numbers of the motif GTGCACCT in the control region of different molecules. Boundaries of the 13 peptide-coding genes were determined by the presence of start and stop codons, and by analogy with other eutherian mtDNAs. Three genes (COIII, NADH3 and NADH4) were not terminated by a stop codon. Comparison among the peptide-coding genes of the horse and eight other mammals...
Science (New York, N.Y.)April 30, 2017
Volume 356, Issue 6336 442-445 doi: 10.1126/science.aam5298
Librado P, Gamba C, Gaunitz C, Der Sarkissian C, Pruvost M, Albrechtsen A, Fages A, Khan N, Schubert M, Jagannathan V, Serres-Armero A, Kuderna LFK....The genomic changes underlying both early and late stages of horse domestication remain largely unknown. We examined the genomes of 14 early domestic horses from the Bronze and Iron Ages, dating to between ~4.1 and 2.3 thousand years before present. We find early domestication selection patterns supporting the neural crest hypothesis, which provides a unified developmental origin for common domestic traits. Within the past 2.3 thousand years, horses lost genetic diversity and archaic DNA tracts introgressed from a now-extinct lineage. They accumulated deleterious mutations later than expected ...
Cooper KL, Sears KE, Uygur A, Maier J, Baczkowski KS, Brosnahan M, Antczak D, Skidmore JA, Tabin CJ.A reduction in the number of digits has evolved many times in tetrapods, particularly in cursorial mammals that travel over deserts and plains, yet the underlying developmental mechanisms have remained elusive. Here we show that digit loss can occur both during early limb patterning and at later post-patterning stages of chondrogenesis. In the 'odd-toed' jerboa (Dipus sagitta) and horse and the 'even-toed' camel, extensive cell death sculpts the tissue around the remaining toes. In contrast, digit loss in the pig is orchestrated by earlier limb patterning mechanisms including downregulation of...
Schroeder DI, Jayashankar K, Douglas KC, Thirkill TL, York D, Dickinson PJ, Williams LE, Samollow PB, Ross PJ, Bannasch DL, Douglas GC, LaSalle JM.Over the last 20-80 million years the mammalian placenta has taken on a variety of morphologies through both divergent and convergent evolution. Recently we have shown that the human placenta genome has a unique epigenetic pattern of large partially methylated domains (PMDs) and highly methylated domains (HMDs) with gene body DNA methylation positively correlating with level of gene expression. In order to determine the evolutionary conservation of DNA methylation patterns and transcriptional regulatory programs in the placenta, we performed a genome-wide methylome (MethylC-seq) analysis of hu...
Nasir L, Campo MS.Bovine papillomavirus (BPV) is perhaps the most extensively studied animal papillomavirus. In cattle BPVs induce benign tumours of cutaneous or mucosal epithelia, called papillomas or warts. Cattle papillomas are benign tumours and generally regress without eliciting any serious clinical problems in the host, but occasionally persist and provide the focus for malignant transformation to squamous cell carcinoma, as in the case of cancer of the urinary bladder and cancer of the upper alimentary canal. BPV is the only papillomavirus that jumps species: the virus also infects equids, and gives ris...
Warmuth V, Eriksson A, Bower MA, Barker G, Barrett E, Hanks BK, Li S, Lomitashvili D, Ochir-Goryaeva M, Sizonov GV, Soyonov V, Manica A.Despite decades of research across multiple disciplines, the early history of horse domestication remains poorly understood. On the basis of current evidence from archaeology, mitochondrial DNA, and Y-chromosomal sequencing, a number of different domestication scenarios have been proposed, ranging from the spread of domestic horses out of a restricted primary area of domestication to the domestication of numerous distinct wild horse populations. In this paper, we reconstruct both the population genetic structure of the extinct wild progenitor of domestic horses, Equus ferus, and the origin and...
Ehlers B, Borchers K, Grund C, Frölich K, Ludwig H, Buhk HJ.A consensus primer PCR approach was used to (i) investigate the presence of herpesviruses in wild and zoo equids (zebra, wild ass, tapir) and to (ii) study the genetic relationship of the herpesvirus of pigeons (columbid herpesvirus 1) to other herpesvirus species. The PCR assay, based on degenerate primers targeting highly conserved regions of the DNA polymerase gene of herpesviruses, was modified by using a mixture of degenerate and deoxyinosine-substituted primers. The applicability of the modification was validated by amplification of published DNA polymerase genes of 16 herpesvirus specie...
Carbone L, Nergadze SG, Magnani E, Misceo D, Francesca Cardone M, Roberto R, Bertoni L, Attolini C, Francesca Piras M, de Jong P, Raudsepp T....Centromere repositioning (CR) is a recently discovered biological phenomenon consisting of the emergence of a new centromere along a chromosome and the inactivation of the old one. After a CR, the primary constriction and the centromeric function are localized in a new position while the order of physical markers on the chromosome remains unchanged. These events profoundly affect chromosomal architecture. Since horses, asses, and zebras, whose evolutionary divergence is relatively recent, show remarkable morphological similarity and capacity to interbreed despite their chromosomes differing co...
Lichtenfels JR, Kharchenko VA, Dvojnos GM.The Equidae (the horse, Equus caballus, the ass, Equus asinus, zebras and their hybrids) are hosts to a great variety of nematode parasites, some of which can cause significant morbidity or mortality if individual hosts are untreated. Worldwide the nematode parasites of horses belong to 7 suborders, 12 families, 29 genera and 83 species. The great majority (19 of 29 genera and 64 of 83 species) are members of the family Strongylidae, which includes the most common and pathogenic nematode parasites of horses. Only the Strongylidae are included in this treatise. The Strongylidae (common name str...
Guo HY, Pang K, Zhang XY, Zhao L, Chen SW, Dong ML, Ren FZ.This study investigated the changes in chemical composition, nitrogen fraction distribution, and AA profile of milk samples obtained during lactation from the Jiangyue breed of donkey in Northwest China. Results showed that donkey milk contained 9.53% total solids, 1.57% protein, 1.16% fat, 6.33% lactose, and 0.4% ash on average, which is more similar to mare and human milk than to the milk of other mammals. Throughout the lactation investigated, pH and density were constant, protein and ash content showed an apparent negative trend (an increase in lactose content during 120 d postpartum, foll...
Knowles DP, Kappmeyer LS, Haney D, Herndon DR, Fry LM, Munro JB, Sears K, Ueti MW, Wise LN, Silva M, Schneider DA, Grause J, White SN, Tretina K....A novel apicomplexan parasite was serendipitously discovered in horses at the United States - Mexico border. Phylogenetic analysis based on 18S rDNA showed the erythrocyte-infective parasite to be related to, but distinct from, Theileria spp. in Africa, the most similar taxa being Theileria spp. from waterbuck and mountain zebra. The degree of sequence variability observed at the 18S rDNA locus also suggests the likely existence of additional cryptic species. Among described species, the genome of this novel equid Theileria parasite is most similar to that of Theileria equi, also a pathogen of...
Vilstrup JT, Seguin-Orlando A, Stiller M, Ginolhac A, Raghavan M, Nielsen SC, Weinstock J, Froese D, Vasiliev SK, Ovodov ND, Clary J, Helgen KM....The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy's zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further charact...
Lippold S, Matzke NJ, Reissmann M, Hofreiter M.DNA target enrichment by micro-array capture combined with high throughput sequencing technologies provides the possibility to obtain large amounts of sequence data (e.g. whole mitochondrial DNA genomes) from multiple individuals at relatively low costs. Previously, whole mitochondrial genome data for domestic horses (Equus caballus) were limited to only a few specimens and only short parts of the mtDNA genome (especially the hypervariable region) were investigated for larger sample sets. Results: In this study we investigated whole mitochondrial genomes of 59 domestic horses from 44 breeds an...
Science (New York, N.Y.)March 10, 2011
Volume 331, Issue 6021 1178-1181 doi: 10.1126/science.1196166
Mihlbachler MC, Rivals F, Solounias N, Semprebon GM.The evolution of high-crowned molars among horses (Family Equidae) is thought to be an adaptation for abrasive diets associated with the spread of grasslands. The sharpness and relief of the worn cusp apices of teeth (mesowear) are a measure of dietary abrasion. We collected mesowear data for North American Equidae for the past 55.5 million years to test the association of molar height and dietary abrasion. Mesowear trends in horses are reflective of global cooling and associated vegetation changes. There is a strong correlation between mesowear and crown height in horses; however, most horse ...
Waller BM, Julle-Daniere E, Micheletta J.Darwin observed that form, and in his view, meaning, of facial behaviour (observable changes in the appearance of the face, often termed facial 'expression') is similar between a wide range of species and concluded that this must be due to a shared ancestral origin. Yet, as with all social behaviours, exactly how to define similarity and determine homology is debated. Facial behaviour is linked to specific facial muscle movements, so one important factor in determining homology is the anatomical basis of facial behaviours that appear similar in both appearance and social function. The Facial A...
Orlando L, Ginolhac A, Raghavan M, Vilstrup J, Rasmussen M, Magnussen K, Steinmann KE, Kapranov P, Thompson JF, Zazula G, Froese D, Moltke I....Second-generation sequencing platforms have revolutionized the field of ancient DNA, opening access to complete genomes of past individuals and extinct species. However, these platforms are dependent on library construction and amplification steps that may result in sequences that do not reflect the original DNA template composition. This is particularly true for ancient DNA, where templates have undergone extensive damage post-mortem. Here, we report the results of the first "true single molecule sequencing" of ancient DNA. We generated 115.9 Mb and 76.9 Mb of DNA sequences from a permafrost-...
Xu S, Luosang J, Hua S, He J, Ciren A, Wang W, Tong X, Liang Y, Wang J, Zheng X.To investigate genetic mechanisms of high altitude adaptations of animals living in the Tibetan Plateau, three mitochondrial genomes (mt-genome) of Tibetan horses living in Naqu (4,500 m) of Tibetan, Zhongdian (3,300 m) and Deqin (3,100 m) of Yunnan province were sequenced. The structures and lengths of these three mt-genomes are similar to the Cheju horse, which is related to Tibetan horses, but little shorter than the Swedish horse. The pair-wise identity of these three horses on nucleotide level is more than 99.3%. When the gene encoding the mitochondrial protein of Tibetan horses was analy...
Mammalian centromeres are associated with highly repetitive DNA (satellite DNA), which has so far hindered molecular analysis of this chromatin domain. Centromeres are epigenetically specified, and binding of the CENPA protein is their main determinant. In previous work, we described the first example of a natural satellite-free centromere on Chromosome 11. Here, we investigated the satellite-free centromeres of by using ChIP-seq with anti-CENPA antibodies. We identified an extraordinarily high number of centromeres lacking satellite DNA (16 of 31). All of them lay in LINE- and AT-rich regio...
