Evolutionary biology and horses focus on the study of the evolutionary processes that have shaped the development, adaptation, and diversification of the Equus genus. This field examines the genetic, morphological, and ecological changes that have occurred over millions of years, leading to the modern horse. Researchers explore the transition from small, multi-toed ancestors to the large, single-toed horses of today, analyzing fossil records, genetic data, and environmental factors that influenced these changes. This page compiles peer-reviewed research studies and scholarly articles that investigate the evolutionary history, genetic adaptations, and ecological interactions of horses, providing insights into their development and survival strategies throughout history.
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...
Murcia PR, Baillie GJ, Stack JC, Jervis C, Elton D, Mumford JA, Daly J, Kellam P, Grenfell BT, Holmes EC, Wood JL.Influenza A viruses are characterized by their ability to evade host immunity, even in vaccinated individuals. To determine how prior immunity shapes viral diversity in vivo, we studied the intra- and interhost evolution of equine influenza virus in vaccinated horses. Although the level and structure of genetic diversity were similar to those in naïve horses, intrahost bottlenecks may be more stringent in vaccinated animals, and mutations shared among horses often fall close to putative antigenic sites.
Petersen JL, Mickelson JR, Cothran EG, Andersson LS, Axelsson J, Bailey E, Bannasch D, Binns MM, Borges AS, Brama P, da Câmara Machado A, Distl O....Horses were domesticated from the Eurasian steppes 5,000-6,000 years ago. Since then, the use of horses for transportation, warfare, and agriculture, as well as selection for desired traits and fitness, has resulted in diverse populations distributed across the world, many of which have become or are in the process of becoming formally organized into closed, breeding populations (breeds). This report describes the use of a genome-wide set of autosomal SNPs and 814 horses from 36 breeds to provide the first detailed description of equine breed diversity. F(ST) calculations, parsimony, and dista...
Huang ZY, de Boer WF, van Langevelde F, Olson V, Blackburn TM, Prins HH.Hosts species for multi-host pathogens show considerable variation in the species' reservoir competence, which is usually used to measure species' potential to maintain and transmit these pathogens. Although accumulating research has proposed a trade-off between life-history strategies and immune defences, only a few studies extended this to host species' reservoir competence. Using a phylogenetic comparative approach, we studied the relationships between some species' life-history traits and reservoir competence in three emerging infectious vector-borne disease systems, namely Lyme disease, W...
Petersen JL, Mickelson JR, Rendahl AK, Valberg SJ, Andersson LS, Axelsson J, Bailey E, Bannasch D, Binns MM, Borges AS, Brama P, da Câmara Machado A....Intense selective pressures applied over short evolutionary time have resulted in homogeneity within, but substantial variation among, horse breeds. Utilizing this population structure, 744 individuals from 33 breeds, and a 54,000 SNP genotyping array, breed-specific targets of selection were identified using an F(ST)-based statistic calculated in 500-kb windows across the genome. A 5.5-Mb region of ECA18, in which the myostatin (MSTN) gene was centered, contained the highest signature of selection in both the Paint and Quarter Horse. Gene sequencing and histological analysis of gluteal muscle...
Carter AM, Enders AC.Epitheliochorial placentation is a derived condition and has evolved separately in strepsirrhine primates and laurasiatherians (pangolins, whales, and hoofed mammals). Usually it is associated with a long gestation period, small litters, and precocial young. Oxygen transfer is facilitated by indenting of the uterine and trophoblast epithelia by maternal and fetal capillaries, respectively. Histotrophic nutrition is important, and adaptations include areolas and hemophagous regions. In pigs and horses, for example, iron is transported as uteroferrin secreted from the uterine glands and taken up...
Leroy G, Mary-Huard T, Verrier E, Danvy S, Charvolin E, Danchin-Burge C.Effective population sizes of 140 populations (including 60 dog breeds, 40 sheep breeds, 20 cattle breeds and 20 horse breeds) were computed using pedigree information and six different computation methods. Simple demographical information (number of breeding males and females), variance of progeny size, or evolution of identity by descent probabilities based on coancestry or inbreeding were used as well as identity by descent rate between two successive generations or individual identity by descent rate. Results: Depending on breed and method, effective population sizes ranged from 15 to 133 ...
Hughes J, Allen RC, Baguelin M, Hampson K, Baillie GJ, Elton D, Newton JR, Kellam P, Wood JL, Holmes EC, Murcia PR.The ability of influenza A viruses (IAVs) to cross species barriers and evade host immunity is a major public health concern. Studies on the phylodynamics of IAVs across different scales - from the individual to the population - are essential for devising effective measures to predict, prevent or contain influenza emergence. Understanding how IAVs spread and evolve during outbreaks is critical for the management of epidemics. Reconstructing the transmission network during a single outbreak by sampling viral genetic data in time and space can generate insights about these processes. Here, we ob...
McFrederick QS, Haselkorn TS, Verocai GG, Jaenike J.Parasites in the genus Onchocerca infect humans, ruminants, camels, horses, suids, and canids, with effects ranging from relatively benign to debilitating. In North America, Onchocerca cervipedis is the sole species known to infect cervids, while at least 5 Onchocerca species infect Eurasian cervids. In this study, we report the discovery of a cervid-parasitizing Onchocerca only distantly related to O. cervipedis. To reconstruct the phylogenetic history of the genus Onchocerca, we used newly acquired DNA sequence from O. cervipedis (from moose in Northwest Territories, Canada) and from the new...
Bujacz A.Serum albumin first appeared in early vertebrates and is present in the plasma of all mammals. Its canonical structure supported by a conserved set of disulfide bridges is maintained in all mammalian serum albumins and any changes in sequence are highly correlated with evolution of the species. Previous structural investigations of mammalian serum albumins have only concentrated on human serum albumin (HSA), most likely as a consequence of crystallization and diffraction difficulties. Here, the crystal structures of serum albumins isolated from bovine, equine and leporine blood plasma are repo...
Xu LX, Yang SL, Lin RY, Yang HB, Li AP, Wan QS.China is one of the principal origins of ponies in the world. We made a comprehensive analysis of genetic diversity and population structure of Chinese ponies based on 174 animals of five indigenous Chinese pony breeds from five provinces using 13 microsatellite markers. One hundred and forty-four alleles were detected; the mean number of effective alleles among the pony breeds ranged from 5.38 (Guizhou) to 6.78 (Sichuan); the expected heterozygosity ranged from 0.82 (Guizhou) to 0.85 (Debao, Sichuan). Although abundant genetic variation was found, the genetic differentiation was low between t...
Parera M, Martrus G, Franco S, Clotet B, Martinez MA.Canine hepacivirus (CHV) was recently identified in domestic dogs and horses. The finding that CHV is genetically the virus most closely related to hepatitis C virus (HCV) has raised the question of whether HCV might have evolved as the result of close contact between dogs and/or horses and humans. The aim of this study was to investigate whether the NS3/4A serine protease of CHV specifically cleaves human mitochondrial antiviral signaling protein (MAVS) and Toll-IL-1 receptor domain-containing adaptor inducing interferon-beta (TRIF). The proteolytic activity of CHV NS3/4A was evaluated using ...
Steiner CC, Mitelberg A, Tursi R, Ryder OA.Short divergence times and processes such as incomplete lineage sorting and species hybridization are known to hinder the inference of species-level phylogenies due to the lack of sufficient informative genetic variation or the presence of shared but incongruent polymorphism among taxa. Extant equids (horses, zebras, and asses) are an example of a recently evolved group of mammals with an unresolved phylogeny, despite a large number of molecular studies. Previous surveys have proposed trees with rather poorly supported nodes, and the bias caused by genetic introgression or ancestral polymorphi...
Bower MA, Whitten M, Nisbet RE, Spencer M, Dominy KM, Murphy AM, Cassidy R, Barrett E, Hill EW, Binns M.The potential future earnings and therefore value of Thoroughbred foals untested in the racing arena are calculated based on the performance of their forebears. Thus, lineage is of key importance. However, previous research indicates that maternally inherited mitochondrial DNA (mtDNA) does not correspond to maternal lineage according to recorded pedigree, casting doubt on the voracity of historic pedigrees. We analysed mtDNA of 296 Thoroughbred horses from 33 maternal lineages and identified an interesting trend. Subsequent to the founding of the Thoroughbred breed in the 16th century, well-po...
Nagy A, Dyson SJ, Murray JK.The popularity of competitive endurance riding is growing worldwide and this has led to considerable changes in the discipline (e.g., fitter and faster horses and different types of injuries), which create challenges to all involved in the sport, including veterinarians. During endurance competitions, horses are closely monitored by veterinarians throughout the ride, with the aim of removing from the competition animals whose welfare appears to be endangered. This close monitoring provides veterinarians with an insight into problems during competitions. However, there is a relatively small amo...
Desgorces FD, Berthelot G, Charmantier A, Tafflet M, Schaal K, Jarne P, Toussaint JF.Running speed in animals depends on both genetic and environmental conditions. Maximal speeds were here analysed in horses, dogs and humans using data sets on the 10 best performers covering more than a century of races. This includes a variety of distances in humans (200-1500 m). Speed has been progressing fast in the three species, and this has been followed by a plateau. Based on a Gompertz model, the current best performances reach 97.4% of maximal velocity in greyhounds to 100.3 in humans. Further analysis based on a subset of individuals and using an 'animal model' shows that running spe...
Makvandi-Nejad S, Hoffman GE, Allen JJ, Chu E, Gu E, Chandler AM, Loredo AI, Bellone RR, Mezey JG, Brooks SA, Sutter NB.Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS) that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many...
Zhang T, Lu H, Chen C, Jiang H, Wu S.In order to protect the genetic resource of native horse breeds, the genetic diversity of mitochondrial DNA (mtDNA) D-loop of three native horse breeds in western China were investigated. Forty-three 600 bp mtDNA D-loop sequences were analyzed by PCR and sequencing techniques, 33 unique haplotypes with 70 polymorphic sites were detected in these horses, which account for 11.67% of 600 bp sequence analyzed, showing the abundant genetic diversity of the three native horse breeds in western China. The Neighbour-Joining (NJ) phylogenetic tree based on 247 bp of 43 D-loop sequences demonstrated the...
Moridi M, Masoudi AA, Vaez Torshizi R, Hill EW.To understand the origin and genetic diversity of Iranian native horses, mitochondrial DNA (mtDNA) D-loop sequences were generated for 95 horses from five breeds sampled in eight geographical locations in Iran. Sequence analysis of a 247-bp segment revealed a total of 27 haplotypes with 38 polymorphic sites. Twelve of 19 mtDNA haplogroups were identified in the samples. The most common haplotypes were found within haplogroup X2. Within-population haplotype and nucleotide diversities of the five breeds ranged from 0.838 ± 0.056 to 0.974 ± 0.022 and 0.011 ± 0.002 to 0.021 ± 0.001 res...
Vaughan JA, Tkach VV, Greiman SE.Digeneans are endoparasitic flatworms with complex life cycles and distinct life stages that parasitize different host species. Some digenean species harbour bacterial endosymbionts known as Neorickettsia (Order Rickettsiales, Family Anaplasmataceae). Neorickettsia occur in all life stages and are maintained by vertical transmission. Far from benign however, Neorickettsia may also be transmitted horizontally by digenean parasites to their vertebrate definitive hosts. Once inside, Neorickettsia can infect macrophages and other cell types. In some vertebrate species (e.g. dogs, horses and humans...
Głażewska I, Prusak B, Gralak B.The goal of this study was to demonstrate the usefulness of pedigree data in studies of mitochondrial DNA diversity in dogs and horses. Pedigree information allows for precisely choosing animals with distinct haplotypes for analysis, makes it possible to find rare haplotypes present exclusively in single individuals and helps to evaluate haplotype frequencies at the present and in the past. Estimating founder contributions to gene pools enables evaluating the parts of gene pools observed with the help of mtDNA analysis. An important aspect is also the financial benefits: using pedigree data, r...
Warmuth V, Manica A, Eriksson A, Barker G, Bower M.Many events in the history of eastern Eurasia, including the process of domestication itself, the initial spread of domestic horses and subsequent movements, are believed to have affected the genetic structure of domestic horse populations in this area. We investigated levels of within- and between-population genetic diversity in 'non-breed horses' (working horses sampled in remote areas) from 17 locations in Asia and parts of Eastern Europe, using 26 autosomal microsatellite loci. Non-breed horses have not been subject to the same intensity of artificial selection and closed breeding as have ...
Kim DS, Kim DW, Kim MY, Nam SH, Choi SH, Kim RN, Kang A, Kim A, Park HS.A conjoined gene is defined as one formed at the time of transcription by combining at least part of one exon from each of two or more distinct genes that lie on the same chromosome, in the same or opposite orientation, which translate independently into different proteins. We comparatively studied the extent of conjoined genes in thirteen genomes by analyzing the public databases of expressed sequence tags and mRNA sequences using a set of computational tools designed to identify conjoined genes on the same DNA strand or opposite DNA strands of the same genomic locus. The CACG database, avail...
Ginolhac A, Vilstrup J, Stenderup J, Rasmussen M, Stiller M, Shapiro B, Zazula G, Froese D, Steinmann KE, Thompson JF, Al-Rasheid KA, Gilbert TM....Second-generation sequencing technologies have revolutionized our ability to recover genetic information from the past, allowing the characterization of the first complete genomes from past individuals and extinct species. Recently, third generation Helicos sequencing platforms, which perform true Single-Molecule DNA Sequencing (tSMS), have shown great potential for sequencing DNA molecules from Pleistocene fossils. Here, we aim at improving even further the performance of tSMS for ancient DNA by testing two novel tSMS template preparation methods for Pleistocene bone fossils, namely oligonucl...
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...
Álvarez I, Fernández I, Lorenzo L, Payeras L, Cuervo M, Goyache F.Pedigree information and 179 mtDNA sequences from two endangered Spanish horse breeds, the Asturcón pony (143) and the Mallorquí horse (36), were analysed to asses: (i) the pedigree and molecular maternal genetic diversity of the two breeds; (ii) the concordance between the dam lines recorded in the corresponding studbooks and the mtDNA haplotypes identified; and (iii) to assess the losses of maternal genetic variability occurred from the foundation of the studbooks to present. Up to 50 Asturcón and 18 Mallorquí founder dam lines were identified in the studbooks analysed. Up to 315 Asturc...
Brinkmann L, Gerken M, Riek A.Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T(a)), subcutaneous temperature (T(s)), locomotor activity (LA), lying time, resting heart rate, body ...
Ma H, Wu Y, Xiang H, Yang Y, Wang M, Zhao C, Wu C.There are large populations of indigenous horse () in China and some other parts of East Asia. However, their matrilineal genetic diversity and origin remained poorly understood. Using a combination of mitochondrial DNA (mtDNA) and hypervariable region (HVR-1) sequences, we aim to investigate the origin of matrilineal inheritance in these domestic horses. Methods: To investigate patterns of matrilineal inheritance in domestic horses, we conducted a phylogenetic study using 31 mtDNA genomes together with 317 others from the GenBank. In terms of the updated phylogeny, a total of 5,180 horse mit...
Sharman P, Wilson AJ.Several studies over recent decades have reported a lack of contemporary improvement in thoroughbred racehorse speed, despite apparent additive genetic variance and putatively strong selection. More recently, it has been shown that some phenotypic improvement is ongoing, but rates are low in general and particularly so over longer distances. Here we used pedigree-based analysis of 692,534 records from 76,960 animals to determine whether these phenotypic trends are underpinned by genetic selection responses, and to evaluate the potential for more rapid improvement. We show that thoroughbred spe...
Li Y, Liu Y, Wang M, Lin X, Li Y, Yang T, Feng M, Ling Y, Zhao C.The Chakouyi horse is an ancient Chinese indigenous horse breed distributed in Gansu Province in northwestern China, and is also one of the key breeds protected by the government. However, the origin of the Chakouyi horse remains unclear. As it is distributed in a key region of the Silk Road, it was speculated that the origin of the Chakouyi horse might involve the foreign horse breeds found along this ancient commercial artery. In this study, whole-genome resequencing data of 12 horse breeds, including both indigenous and foreign horses, were applied to reveal the genetic relationships betwee...
Onogi A, Shirai K, Amano T.Because native breeds can serve as genetic resources for adapting to environment changes, their conservation is important for future agroecosystems. Using pedigree analysis, we investigated genetic diversity and inbreeding in Japanese Hokkaido native horses, which have adapted to a cold climate and roughage diet. Genetic diversity was measured as the number of founders and the effective number of founders, ancestors and genomes. All metrics imply a decrease in genetic diversity. A comparison of these metrics suggested that pedigree bottlenecks contributed more than did random gene losses to th...
Dell AC, Curry MC, Yarnell KM, Starbuck GR, Wilson PB.Genetic diversity and maternal ancestry line relationships amongst a sample of 96 Cleveland Bay horses were investigated using a 479bp length of mitochondrial D-loop sequence. The analysis yielded at total of 11 haplotypes with 27 variable positions, all of which have been described in previous equine mitochondrial DNA d-loop studies. Four main haplotype clusters were present in the Cleveland Bay breed describing 89% of the total sample. This suggests that only four principal maternal ancestry lines exist in the present-day global Cleveland Bay population. Comparison of these sequences with ot...
Tang Y, Liu G, Zhao S, Li K, Zhang D, Liu S, Hu D.Major histocompatibility complex (MHC) genes are the most polymorphic in vertebrates and the high variability in many MHC genes is thought to play a crucial role in pathogen recognition. The MHC class II locus DQA polymorphism was analyzed in the endangered Przewalski's horse, , a species that has been extinct in the wild and all the current living individuals descend from 12 founders. We used the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) to detect the polymorphism within the MHC DQA in 31 Przewalski's horses from two reintroduced populations. Consequently, o...
Yoon SH, Lee W, Ahn H, Caetano-Anolles K, Park KD, Kim H.The Thoroughbred horse breed was developed primarily for racing, and has a significant contribution to the qualitative improvement of many other horse breeds. Despite the importance of Thoroughbred racehorses in historical, cultural, and economical viewpoints, there was no temporal and spatial dynamics of them using the mitogenome sequences. To explore this topic, the complete mitochondrial genome sequences of 14 Thoroughbreds and two Przewalski's horses were determined. These sequences were analyzed together along with 151 previously published horse mitochondrial genomes from a range of breed...
Lancioni H, Cardinali I, Giontella A, Antognoni MT, Miglio A.In the last decades, Italy as well as other developed countries have registered a decrease in the population size of many local horse breeds. The continuous crossbreeding has determined the dilution of genetic heritage of several native breeds. The Italian Heavy Draught Horse (IHD) is the only autochthonous Italian coldblooded horse among these breeds; therefore, it represents a resource to be preserved. In 1927, the first generation of this breed was officially created by crossing different Heavy Draught horses with local mares and recorded in a Studbook. Methods: To provide the first compreh...
Tyson R, Graham JP, Colahan PT, Berry CR.An 8-month-old miniature horse filly was presented for evaluation of severe rotational and angular limb deformities of the thoracic and pelvic limbs. On radiographic examination, complete ulnas and fibulas were identified. These findings are consistent with a condition previously described as a form of atavism. The term atavism is used to describe the reappearance of a trait or character that was seen in all earlier evolutionary specimens of a particular species, but has not been seen in recent ancestors. The atavistic traits of complete ulnas and fibulas have previously been described in Wels...
Mousavi SF, Razmkabir M, Rostamzadeh J, Seyedabadi HR, Naboulsi R, Petersen JL, Lindgren G.Indigenous Iranian horse breeds were evolutionarily affected by natural and artificial selection in distinct phylogeographic clades, which shaped their genomes in several unique ways. The aims of this study were to evaluate the genetic diversity and genomewide selection signatures in four indigenous Iranian horse breeds. We evaluated 169 horses from Caspian (n = 21), Turkmen (n = 29), Kurdish (n = 67), and Persian Arabian (n = 52) populations, using genomewide genotyping data. The contemporary effective population sizes were 59, 98, 102, and 113 for Turkmen, Caspian, Persian Ar...
Yuan JX, Hou XD, Barlow A, Preick M, Taron UH, Alberti F, Basler N, Deng T, Lai XL, Hofreiter M, Sheng GL.The extant diversity of horses (family Equidae) represents a small fraction of that occurring over their evolutionary history. One such lost lineage is the subgenus Sussemionus, which is thought to have become extinct during the Middle Pleistocene. However, recent molecular studies and morphological analysis have revealed that one of their representatives, E. ovodovi, did exist in Siberia during the Late Pleistocene. Fossil materials of E. ovodovi have thus far only been found in Russia. In this study, we extracted DNA from three equid fossil specimens excavated from northeastern China dated a...
Zhao RY, Zhao YP, Li B, Bou G, Zhang XZ, Mongke T, Bao T, Gereliin S, Gereltuuin T, Li C, Bai DY, Dugarjaviin ML.Mammalian coat color is one of the first phenotypic changes resulting from positive selection by humans, and it serves important roles in genetic and evolutionary processes. Among them, horses show a broad variety of coat color patterns, based on which it is difficult to distinguish the real phenotypes, resulting in confused records in horse breed registration. Thus, research in the genetic mechanisms on the development of coat color patterns is significant in horse reproduction and breeding. With the recent establishment of genomics and sequencing technologies, there are significant advances ...
Nam B, Mekuria Z, Carossino M, Li G, Zheng Y, Zhang J, Cook RF, Shuck KM, Campos JR, Squires EL, Troedsson MHT, Timoney PJ, Balasuriya UBR.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a reproductive and respiratory disease of horses. Following natural infection, 10 to 70% of infected stallions can become carriers of EAV and continue to shed virus in the semen. In this study, sequential viruses isolated from nasal secretions, buffy coat cells, and semen of seven experimentally infected and two naturally infected EAV carrier stallions were deep sequenced to elucidate the intrahost microevolutionary process after a single transmission event. Analysis of variants from nasal secretions and buffy...
Goh G, Raudsepp T, Durkin K, Wagner ML, Schäffer AA, Agarwala R, Tozaki T, Mickelson JR, Chowdhary BP.High-resolution physically ordered gene maps for equine homologs of human chromosome 5 (HSA5), viz., horse chromosomes 14 and 21 (ECA14 and ECA21), were generated by adding 179 new loci (131 gene-specific and 48 microsatellites) to the existing maps of the two chromosomes. The loci were mapped primarily by genotyping on a 5000-rad horse x hamster radiation hybrid panel, of which 28 were mapped by fluorescence in situ hybridization. The approximately fivefold increase in the number of mapped markers on the two chromosomes improves the average resolution of the map to 1 marker/0.9 Mb. The improv...
Eronen JT, Evans AR, Fortelius M, Jernvall J.One of the classic examples of faunal turnover in the fossil record is the Miocene transition from faunas dominated by anchitheriine horses with low-crowned molar teeth to faunas with hipparionine horses characterized by high-crowned teeth. The spread of hipparionine horses is associated with increased seasonality and the expansion of open habitats. It is generally accepted that anchitheriine horses did not display an evolutionary increase in tooth crown height prior to their extinction. Nevertheless, to test whether anchitheriines showed any changes interpretable as adaptation to local condit...
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...
Waller AS, Robinson C.The host-restricted bacterium Streptococcus equi is the causative agent of equine strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation of the lymph nodes of the head and neck, leading to significant welfare and economic cost. S. equi is believed to have evolved from an ancestral strain of Streptococcus zooepidemicus, an opportunistic pathogen of horses and other animals. Comparison of the genome of S. equi strain 4047 with those of S. zooepidemicus identified examples of gene loss due to mutation and deletion, and gene ga...
Looft C, Paul S, Philipp U, Regenhard P, Kuiper H, Distl O, Chowdhary BP, Leeb T.Defensins are a family of evolutionary ancient antimicrobial peptides consisting of three sub-families: alpha-, beta- and theta-defensins. This investigation was focused on the genomic characterization of equine beta-defensins and the investigation of the potential clustering of beta-defensin genes in the equine genome. Six genomic BAC clones were isolated from the CHORI-241 library and one of these was mapped by FISH to ECA 27q17. This location was confirmed by RH-mapping. The contiguous 212 kb sequence of this clone was determined. Sequence analysis revealed the identification of ten pseudog...
May-Davis S, Hunter R, White R.In this study, we examined the ventral process of C6 in extinct and extant (sister taxa to only) with the purpose of describing normal morphology and identifying anomalous variations relevant to recent studies describing a congenital malformation in . Overall, 83 specimens from 9 museums and 3 research/educational facilities were examined, totalling 71 extinct specimens from 12 species and 12 extant specimens from 5 species. The lateral view revealed that a large convexity exists in the ventral process between the cranial ventral tubercle (CrVT) and the caudal ventral tubercle (CVT) in the e...
Xu LX, Yang SL, Lin RY, Yang HB, Li AP, Wan QS.China is one of the principal origins of ponies in the world. We made a comprehensive analysis of genetic diversity and population structure of Chinese ponies based on 174 animals of five indigenous Chinese pony breeds from five provinces using 13 microsatellite markers. One hundred and forty-four alleles were detected; the mean number of effective alleles among the pony breeds ranged from 5.38 (Guizhou) to 6.78 (Sichuan); the expected heterozygosity ranged from 0.82 (Guizhou) to 0.85 (Debao, Sichuan). Although abundant genetic variation was found, the genetic differentiation was low between t...
Self Davies ZT, Spence AJ, Wilson AM.Horse locomotion is remarkably economical. Here, we measure external mechanical work of the galloping horse and relate it to published measurements of metabolic cost. Seven Thoroughbred horses were galloped (ridden) over force plates, under a racing surface. Twenty-six full strides of force data were recorded and used to calculate the external mechanical work of galloping. The mean sum of decrements of mechanical energy was -876 J (±280 J) per stride and increments were 2163 J (±538 J) per stride as horses were accelerating. Combination with published values for internal work and metabolic c...
Frontiers in geneticsOctober 5, 2022
Volume 13 944933 doi: 10.3389/fgene.2022.944933
Xu B, Yang G, Jiao B, Zhu H. The domestication of horses has played critical roles in human civilizations. The excavation of ancient horse DNA provides crucial data for studying horse domestication. Studies of horse domestication can shed light on the general mechanisms of animal domestication. We wish to explore the gene transcription regulation by long noncoding RNAs (lncRNAs) that influence horse domestication. First, we assembled the ancient DNA sequences of multiple horses at different times and the genomes of horses, donkeys, and Przewalski horses. Second, we extracted sequences of lncRNA genes shared in ancient ...
Kavanagh KD, Bailey CS, Sears KE.Previous work comparing the developmental mechanisms involved in digit reduction in horses with other mammals reported that horses have only a 'single digit', with two flanking metapodials identified as remnants of digit II and IV. Here we show that early embryos go through a stage with five digit condensations, and that the flanking splint metapodials result from fusions of the two anterior digits I and II and the two posterior digits IV and V, in a striking parallel between ontogeny and phylogeny. Given that even this most extreme case of digit reduction exhibits primary pentadactyly, we re...
Bayerova Z, Janova E, Matiasovic J, Orlando L, Horin P.Immunity-related genes are a suitable model for studying effects of selection at the genomic level. Some of them are highly conserved due to functional constraints and purifying selection, while others are variable and change quickly to cope with the variation of pathogens. The SLC11A1 gene encodes a transporter protein mediating antimicrobial activity of macrophages. Little is known about the patterns of selection shaping this gene during evolution. Although it is a typical evolutionarily conserved gene, functionally important polymorphisms associated with various diseases were identified in ...
Delsol N, Stucky BJ, Oswald JA, Reitz EJ, Emery KF, Guralnick R.Unlike other European domesticates introduced in the Americas after the European invasion, equids (Equidae) were previously in the Western Hemisphere but were extinct by the late Holocene era. The return of equids to the Americas through the introduction of the domestic horse (Equus caballus) is documented in the historical literature but is not explored fully either archaeologically or genetically. Historical documents suggest that the first domestic horses were brought from the Iberian Peninsula to the Caribbean in the late 15th century CE, but archaeological remains of these early introduct...
Open life sciencesSeptember 26, 2022
Volume 17, Issue 1 1269-1281 doi: 10.1515/biol-2022-0487
Pan J, Purev C, Zhao H, Zhang Z, Wang F, Wendoule N, Qi G, Liu Y, Zhou H.The Mongolian horses have excellent endurance and stress resistance to adapt to the cold and harsh plateau conditions. Intraspecific genetic diversity is mainly embodied in various genetic advantages of different branches of the Mongolian horse. Since people pay progressive attention to the athletic performance of horse, we expect to guide the exercise-oriented breeding of horses through genomics research. We obtained the clean data of 630,535,376,400 bp through the entire genome second-generation sequencing for the whole blood of four Abaga horses and ten Wushen horses. Based on the data an...
Vega-Pla JL, Calderón J, Rodríguez-Gallardo PP, Martinez AM, Rico C.In the 1980s, a conservation programme involving a feral horse population, the Retuertas horses from the Guadalquivir marshes, was started in the Doñana National Park. The analysis of an extensive genetic survey of this population, which now numbers 100 animals, and 10 additional European and North African breeds using DNA polymorphisms from 22 microsatellites is presented. Highly significant fixation indexes were obtained for all pairwise comparisons between the Retuertas population and other breeds. A population neighbour-joining breed phenogram was built using different distance measures, ...
Science (New York, N.Y.)June 24, 1983
Volume 220, Issue 4604 1403-1404 doi: 10.1126/science.220.4604.1403
Berger J.The identities, sexes, and reproductive status of groups of wild horses (Equus caballus) living in the Great Basin Desert of North America were known prior to their deaths on ridgelines. Another group of very young horses died on a quagmire. Snow accumulation or drought was apparently responsible for the mass deaths. These data have implications for reconstructing some aspects of the social structure of fossil mammals on the basis of skewed sex or age ratios in bone assemblages.
