Search Results (13)

Captive environments can have detrimental effects on the health of Equus species. However, due to the limitations of available databases, the types and abundance of pathogenic bacteria in Equus species remain largely unknown. Therefore, this study aimed to explore pathogenic gut bacteria in wild and captive Equus species. Using 16S rRNA gene sequencing and a comprehensive multiple bacterial pathogen detection database, we compared the pathogenic gut bacterial profiles of three Equus species (Equus ferus przewalskii, E. hemionus, and E. kiang) across different captive and wild environments. The pheatmap revealed that the three Equus species living in different captive environments showed convergence in their pathogenic gut bacterial composition. Captive Equus species had significantly enriched zoonotic bacteria, whereas wild Equus species had significantly enriched animal pathogenic bacteria. These findings suggest that a captive environment may increase the risk of zoonotic bacterial transmission between Equus species and humans. We hope that this study can provide a reasonable scientific basis for the management and protection of captive Equus species. Full article

Over 40 years ago, scientists imagined ways cloning could aid conservation of threatened taxa. The cloning of Dolly the sheep from adult somatic cells in 1996 was the breakthrough that finally enabled the conservation potential of the technology. Until the 2020s, conservation cloning research efforts yielded no management applications, leading many to believe cloning is not yet an effective conservation tool. In strong contrast, domestic taxa are cloned routinely for scientific and commercial purposes. In this review, we sought to understand the reasons for these divergent trends. We scoured peer-reviewed and gray literature and sent direct inquiries to scientists to analyze a more comprehensive history of the field than was analyzed in previous reviews. While most previous reviewers concluded that a lack of reproductive knowledge of wildlife species has hindered advances for wider conservation applications, we found that resource limitations (e.g., numbers of surrogates, sustainable funding) and widely held misconceptions about cloning are significant contributors to the stagnation of the field. Recent successes in cloning programs for the endangered black-footed ferret (Mustela nigripes) and Przewalski’s horse (Equus przewalskii), the world’s first true applied-conservation cloning efforts, are demonstrating that cloning can be used for significant conservation impact in the present. When viewed alongside the long history of cloning achievements, these programs emphasize the value of investing in the science and resources needed to meaningfully integrate cloning into conservation management, especially for species with limited genetic diversity that rely on the maintenance of small populations for many generations while conservationists work to restore habitat and mitigate threats in the wild. Full article

Cloning from historically cryopreserved cells offers a potential means to restore lost genetic variation or increase the representation of particular lineages within bottlenecked species, provided such biobanked materials are archived for such genetic rescue applications. One species for which cloning can provide genetic management benefits is Przewalski’s horse, Equus przewalskii. All ~1800 living Przewalski’s horses, distributed across ex situ breeding facilities and in situ reintroduction sites, are descended from one or more of the five founder lineages established by the 12 horses captured from the wild between 1898 and 1947. Since the 1970s, the San Diego Zoo Wildlife Alliance Biodiversity Bank’s Frozen Zoo^® (Escondido, CA, USA) has biobanked cells or tissues of 575 individuals spanning many generations. A pedigree analysis of a subset of deceased individuals represented in the San Diego Zoo Wildlife Alliance Biodiversity Bank’s Frozen Zoo^® revealed an underrepresented male that lived from 1975 to 1998, Studbook Number 615 (also known as Kuporovitch), who would be of high value for breeding if cloned. Here, we report that two healthy clones were produced from this cell line using cross-species somatic cell nuclear transfer from 2020 to 2023. Their identification as clones was verified by a standard horse-pedigree genotyping panel, and, for one clone, a whole genome sequencing comparison to the original donor was performed. This is the first time that multiple healthy clones surviving the perinatal period have been produced for an endangered species. Full article

Understanding social relationships in at-risk species held in captivity is vital for their welfare and potential reintroduction. In social species like the Przewalski’s horse (Equus ferus przewalskii), daily time allocation and space use may be influenced by social structure and, in turn, reflect welfare. Here, we identify social relationships, time budgets, and spatial distribution of a group of nine older (aged 6–21 years) male Przewalski’s horses living in a non-breeding (bachelor) group. We conducted our work at the Askania-Nova Biosphere Reserve, over 65 h of observation in summer, 2015. Horses formed stronger social bonds with individuals of similar gregariousness and dominance levels. Social-network analysis identified three distinct subgroups with significant differences in locomotion, social behaviour, and foraging. However, resting and vigilance behaviour remained similar across the subgroups. Behavioural synchrony across all activities was higher within subgroups than between. Space use was also affected by subgroup membership, with some horses overusing or underusing critical resource areas like hay and water. These findings suggest opportunities to improve welfare by adjusting space and resource distribution, particularly for more submissive individuals. Our approach may also aid in selecting reintroduction candidates by considering social characteristics alongside health, genetic, and other factors. Full article

Diarrhea serves as a vital health indicator for assessing wildlife populations post-reintroduction. Upon release into the wild, wild animals undergo adaptation to diverse habitats and dietary patterns. While such changes prompt adaptive responses in the fecal microbiota, they also render these animals susceptible to gastrointestinal diseases, particularly diarrhea. This study investigates variations in fecal microorganisms and hormone levels between diarrhea-afflicted and healthy Przewalski’s horses. The results demonstrate a significant reduction in the alpha diversity of the fecal bacterial community among diarrheal Przewalski’s horses, accompanied by notable alterations in taxonomic composition. Firmicutes, Proteobacteria, and Bacteroidetes emerge as dominant phyla across all fecal samples, irrespective of health status. However, discernible differences in fecal bacterial abundance are observed between healthy and diarrhea-stricken individuals at the genus level, specifically, a diminished relative abundance of Pseudobutyrivibrio is observed. The majority of the bacteria that facilitate the synthesis of short-chain fatty acids, Christensenellaceae_R_7_group (Christensenellaceae), NK4A214_group (Ruminococcus), Lachnospiraceae_XPB1014_group (Lachnospiraceae), [Eubacterium]_coprostanoligenes_group (Eubacterium), Rikenellaceae_RC9_gut_group, Lachnospiraceae_AC2044_group (Lachnospiraceae), and Prevotellaceae_UcG_001 (Prevotella) are noted in diarrhea-affected Przewalski’s horses, while Erysipelotrichaceae, Phoenicibacter, Candidatus_Saccharimonas (Salmonella), and Mogibacterium are present in significantly increased amounts. Moreover, levels of immunoglobulin IgA and cortisol are significantly elevated in the diarrhea group compared with the non-diarrhea group. Overall, this study underscores substantial shifts in fecal bacterial diversity, abundance, and hormone levels in Przewalski’s horses during episodes of diarrhea. Full article

This paper presents historical and evolutionary insights into the “tarpan” group of small horses by examining molar tooth enamel ultrastructure. Mathematical methodologies were applied to enhance the analysis. Tooth enamel from species such as Equus gmelini (tarpan), E. latipes, and E. hydruntinus from Pleistocene Ukrainian localities, E. przewalskii from the Chornobyl Exclusion Zone in Ukraine, and E. caballus form sylvaticus (Polish konik) from Roztocze National Park, Poland, underwent scanning microscope examination. Measurements of enamel structures, including prisms (PE) and interprismatic matrix (IPM), were conducted, with the K-index used as their ratio, categorized by enamel type (I, II, III). The findings confirmed that the crystal structures of enamel in these horse groups vary based on genus evolution, diet, and environmental conditions, shaping the enamel’s morphological features. Through analysis, clusters were identified, allowing for potential reconstructions of relationships among study groups. The results revealed distinct differences between species, enabling their classification within an established phenogram. Two primary clusters emerged: one consisting of extinct small horse forms from diverse localities and another grouping modern forms. Notably, the Late Pleistocene European species E. latipes showed close affinities to the latter cluster. Full article

In mammals, centromeres are epigenetically specified by the histone H3 variant CENP-A and are typically associated with satellite DNA. We previously described the first example of a natural satellite-free centromere on Equus caballus chromosome 11 (ECA11) and, subsequently, on several chromosomes in other species of the genus Equus. We discovered that these satellite-free neocentromeres arose recently during evolution through centromere repositioning and/or chromosomal fusion, after inactivation of the ancestral centromere, where, in many cases, blocks of satellite sequences were maintained. Here, we investigated by FISH the chromosomal distribution of satellite DNA families in Equus przewalskii (EPR), demonstrating a good degree of conservation of the localization of the major horse satellite families 37cen and 2PI with the domestic horse. Moreover, we demonstrated, by ChIP-seq, that 37cen is the satellite bound by CENP-A and that the centromere of EPR10, the ortholog of ECA11, is devoid of satellite sequences. Our results confirm that these two species are closely related and that the event of centromere repositioning which gave rise to EPR10/ECA11 centromeres occurred in the common ancestor, before the separation of the two horse lineages. Full article

This review summarizes studies on Przewalski’s horse since its extinction in the wild in the 1960s, with a focus on the reintroduction projects in Mongolia and China, with current population status. Historical and present distribution, population trends, ecology and habitats, genetics, behaviors, conservation measures, actual and potential threats are also reviewed. Captive breeding and reintroduction projects have already been implemented, but many others are still under considerations. The review may help to understand the complexity of problem and show the directions for effective practice in the future. Full article

Intestinal microbiota play an important role in the survival of the host. However, no study to date has elucidated the adjustment of intestinal microbiota of the host during rewilding. Thus, this study aims to describe the intestinal bacterial community of reintroduced Przewalski’s horse (RPH) after being released into their original habitat for approximately 20 years in comparison with that of captive Przewalski’s horse (CPH), sympatric domestic horse (DH) and Mongolian wild ass (MWA) by sequencing the 16S rRNA gene. The results showed that the prevalent bacterial communities were different among CPHs, RPHs, DHs and MWAs at the family level. NMDS and ANOSIM analysis showed that the pattern of bacterial community composition in captive equines was distinct from that in the wild groups. It is shown that some bacteria had significant differences among different taxa (p < 0.001), such as Firmicutes, Bacteroidetes, Armatimonadetes, Clostrida, Bacteroidia, Clostridiales, Bacteroidales, Rikenellaceae and Bacteroidales_UCG-001. These bacteria were associated with the transition from in captive to in the wild (CPH and RPH), which reflected the change of environmental conditions. Meanwhile, Proteobacteria, Clostridia, Bacilli, Negativicutes, Gammaproteobacteria, Clostridiales, Bacillales, Selenomonadales, Pseudomonadales and Planococcaceae were the changed groups among RPHs, MWAs and DHs, which are related to feeding habits and diseases. Our results clearly showed the differences between intestinal microbiota in reintroduced animals and wild animals and led us to understand the survival state of reintroduced animals in the wild. Full article

Discussion of the phylogenetic relations between Plesippus, Allohippus, and Equus. Descriptions and illustrations of 30 Equid extant and fossil species younger than 2 Ma. Particular attention is given to slender forms with short protocones usually referred to ‘Equus altidens’ from Süssenborn and Untermassfeld (Germany), Akhalkalaki and Dmanisi (Georgia), Pirro (Italy), Venta Micena (Spain) and Aïn Hanech (Algeria). Occurrence of Asinine features in fossil taxa from Africa, Greece, Mongolia, and North-Eastern Siberia. Supplementary Materials include additional discussions and photographs of fossils in particular from Süssenborn (especially those referred to E. altidens and E. marxi by Reichenau) and from Dmanisi from where a new species is described. Full article

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, Equus przewalskii, 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, only seven alleles were identified, with only four presenting in each population. In comparison with other mammals, the Przewalski’s horse demonstrated less MHC variation. The nucleotide genetic distance of the seven ELA-DQA alleles was between 0.012 and 0.161. The Poisson corrected amino acid genetic distance of the founded alleles was 0.01–0.334. The allele and genotype frequencies of both reintroduced populations of Przewalski’s horse deviated from the Hardy–Weinberg equilibrium. Specific MHC DQA alleles may have been lost during the extreme bottleneck event that this species underwent throughout history. We suggest the necessity to detect the genetic background of individuals prior to performing the reintroduction project. Full article

The 55-million-year history of equine phylogeny has been well-documented from the skeletal record; however, this is less true for the soft tissue structures that are now vestigial in modern horse. A recent study reported that two ligamentous structures resembling functional interosseous muscle II and IV were evident in Dutch Konik horses. The current study investigates this finding and compares it to members of the genus Equus to identify either a breed anomaly or functional primitive trait. Distal limbs (n = 574) were dissected from four species of Equus; E. caballus, E. asinus, E. przewalskii and E. quagga boehmi. E. caballus is represented by 18 breeds of horse, including the primitive Dutch Konik’. The interosseous muscle II and IV were evident in all four species, but only two breeds of E. caballus expressed this trait-the Dutch Konik and Bosnian Mountain Horse. These two breeds were the only close descendants of the extinct Equus ferus ferus (Tarpan) represented in this study. In conclusion, the interosseous muscle II and IV originated from the distal nodule of metacarpal II and IV, respectively, and inserted into the corresponding branches of interosseous muscle III proximal to the sesamoids. This suggests a functional role in medial and lateral joint stability and a primitive trait in modern equids. Full article

In Europe, the interest in introducing megaherbivores to achieve ambitious habitat restoration goals is increasing. In this study, we present the results of a one-year monitoring program in a rewilding project in Germany (Doeberitzer Heide), where European bison (Bison bonasus) and Przewalski’s horses (Equus ferus przewalskii) were introduced for ecological restoration purposes. Our objectives were to investigate diet and habitat preferences of Przewalski’s horses and European bison under free-choice conditions without fodder supplementation. In a random forest classification approach, we used multitemporal RapidEye time series imagery to map the diversity of available habitats within the study area. This spatially explicit habitat distribution from satellite imagery was combined with direct field observations of seasonal diet preferences of both species. In line with the availability of preferred forage plants, European bison and Przewalski’s horses both showed seasonal habitat preferences. Because of their different preferences for forage plants, they did not overlap in habitat use except for a short time in the colder season. European bison used open habitats and especially wet open habitats more than expected based on available habitats in the study area. Comparative foraging and feeding niches should be considered in the establishment of multispecies projects to maximize the outcome of restoration processes. Full article