Genetic Variants Affecting Skeletal Morphology in Domestic Dogs.

Purebred dog breeds provide a powerful resource for the discovery of genetic variants affecting skeletal morphology. Domesticated and subsequently purebred dogs have undergone strong artificial selection for a broad range of skeletal variation, which include both the size and shapes of their bones. While the phenotypic variation between breeds is high, within-breed morphological variation is typically low. Approaches for defining genetic variants associated with canine morphology include quantitative within-breed analyses, as well as across-breed analyses, using breed standards as proxies for individual measurements. The ability to identify variants across the genomes of individual dogs can now be paired with precise measures of morphological variation to define the genetic interactions and the phenotypic effect of variants on skeletal morphology.

3D skin models in domestic animals.

The skin is a passive and active barrier which protects the body from the environment. Its health is essential for the accomplishment of this role. Since several decades, the skin has aroused a strong interest in various fields (for e.g. cell biology, medicine, toxicology, cosmetology, and pharmacology). In contrast to other organs, 3D models were mostly and directly elaborated in humans due to its architectural simplicity and easy accessibility. The development of these models benefited from the societal pressure to reduce animal experiments. In this review, we first describe human and mouse skin structure and the major differences with other mammals and birds. Next, we describe the different 3D human skin models and their main applications. Finally, we review the available models for domestic animals and discuss the current and potential applications.

Progress and challenges in developing organoids in farm animal species for the study of reproduction and their applications to reproductive biotechnologies.

Within the past decades, major progress has been accomplished in isolating germ/stem/pluripotent cells, in refining culture medium and conditions and in establishing 3-dimensional culture systems, towards developing organoids for organs involved in reproduction in mice and to some extent in humans. Haploid male germ cells were generated in vitro from primordial germ cells. So were oocytes, with additional support from ovarian cells and subsequent follicle culture. Going on with the female reproductive tract, spherical oviduct organoids were obtained from adult stem/progenitor cells. Multicellular endometrial structures mimicking functional uterine glands were derived from endometrial cells. Trophoblastic stem cells were induced to form 3-dimensional syncytial-like structures and exhibited invasive properties, a crucial point for placentation. Finally, considering the embryo itself, pluripotent embryonic cells together with additional extra-embryonic cells, could self-organize into a blastoid, and eventually into a post-implantation-like embryo. Most of these accomplishments have yet to be reached in farm animals, but much effort is devoted towards this goal. Here, we review the progress and discuss the specific challenges of developing organoids for the study of reproductive biology in these species. We consider the use of such organoids in basic research to delineate the physiological mechanisms involved at each step of the reproductive process, or to understand how they are altered by environmental factors relevant to animal breeding. We evaluate their potential in reproduction of animals with a high genetic value, from a breeding point of view or in the context of preserving local breeds with limited headcounts.

Intestinal organoids in farm animals.

In livestock species, the monolayer of epithelial cells covering the digestive mucosa plays an essential role for nutrition and gut barrier function. However, research on farm animal intestinal epithelium has been hampered by the lack of appropriate in vitro models. Over the past decade, methods to culture livestock intestinal organoids have been developed in pig, bovine, rabbit, horse, sheep and chicken. Gut organoids from farm animals are obtained by seeding tissue-derived intestinal epithelial stem cells in a 3-dimensional culture environment reproducing in vitro the stem cell niche. These organoids can be generated rapidly within days and are formed by a monolayer of polarized epithelial cells containing the diverse differentiated epithelial progeny, recapitulating the original structure and function of the native epithelium. The phenotype of intestinal organoids is stable in long-term culture and reflects characteristics of the digestive segment of origin. Farm animal intestinal organoids can be amplified in vitro, cryopreserved and used for multiple experiments, allowing an efficient reduction of the use of live animals for experimentation. Most of the studies using livestock intestinal organoids were used to investigate host-microbe interactions at the epithelial surface, mainly focused on enteric infections with viruses, bacteria or parasites. Numerous other applications of farm animal intestinal organoids include studies on nutrient absorption, genome editing and bioactive compounds screening relevant for agricultural, veterinary and biomedical sciences. Further improvements of the methods used to culture intestinal organoids from farm animals are required to replicate more closely the intestinal tissue complexity, including the presence of non-epithelial cell types and of the gut microbiota. Harmonization of the methods used to culture livestock intestinal organoids will also be required to increase the reproducibility of the results obtained in these models. In this review, we summarize the methods used to generate and cryopreserve intestinal organoids in farm animals, present their phenotypes and discuss current and future applications of this innovative culture system of the digestive epithelium.

Performance of Black Bengal goat: a 50-year review.

Black Bengal goat (BBG) is the most widely recognized legacy goat breed in Bangladesh. The breed is black in color yet likewise earthy, white, or dim colors additionally found. The breed has medium body size with grown-up weight 25-30 kg, little horns, short legs, and tight body structure. The BBG is one of the most compliant, all around adjusted, early maturing, prolific, productive, and tropical disease-resistant goat types of the world that produces incredible quality meat, milk, and skin. The breed is versatile in hot, moist, cruel, climatic conditions and flourishes well on a cacophonous dietary regimen from uncultivable decrepit grounds, residences, riversides, banks, sloping, and hilly territories where crop culture or dairy nourishing is inconceivable. In Bangladesh, the BBG is one of the main red meat-producing small ruminants which shares remarkable local interest during Eid-Ul-Adha, Eid-Ul-Fitr, wedding ceremony, birthday festival, circumcision, memorial programs, and other social celebrations with no social, cultural, and religious limitations. Being little in size, the BBG has been an amazing asset to advance supportable vocations for the negligible, little, and landless ranchers who rely upon free regular grazing lands for raising domesticated animals. Regardless of incredibly exceptional components and features, the production of BBG has not yet been popularized widely since meager consideration has been paid for improving their efficiency. Development of cutting edge hereditary, dietary, and health as well as disease control procedure and utilization of modern management frameworks may procure considerable changes in improving the overall performance of the BBG.

Comparative morphological evaluation of domestic animal cornea.

OBJECTIVE: This study described corneal morphology in different domestic animals using histological and immunohistochemical methods. Specifically, we evaluated the species-specific distribution pattern of cytokeratins (CKs) and aquaporins (AQPs) to assess their contribution to the strength and transparency of the cornea, respectively. PROCEDURES: Corneal sections (2 µm thick) were obtained from 28 pigs, 11 cows, two goats, six horses, four dogs, and five cats and stained with hematoxylin-eosin and periodic acid-Schiff (PAS) reaction. Immunohistochemistry was also performed using CK1 to 3 and AQP1 and 5 antibodies. RESULTS: Domestic animal corneas were composed of corneal epithelium, stroma, Descemet's membrane, and corneal endothelium. Bowman's layer was not detected using the PAS reaction. The three-layered epithelium was thinnest in carnivores and thickest in equines and bovines. CKs were demonstrated immunohistochemically in all species examined, especially in the most superficial layer of the corneal epithelium. CKs were more widely distributed in canine and feline corneal epithelial cell layers compared to other species. The corneal monolayer endothelium was immunostained with AQP1 in all species examined, and it was also present in stromal keratocytes in a species-specific manner. In contrast, AQP5 was exclusively localized to the corneal epithelium. Epithelial staining patterns varied markedly between species, and the widest distribution of AQP5 was demonstrated in feline epithelial cell layers. CONCLUSIONS: Differences in the distribution of CKs and AQPs in various species suggest species differences in the maintenance of structural integrity and fluid balance.

A simple genetic architecture underlies morphological variation in dogs.

Domestic dogs exhibit tremendous phenotypic diversity, including a greater variation in body size than any other terrestrial mammal. Here, we generate a high density map of canine genetic variation by genotyping 915 dogs from 80 domestic dog breeds, 83 wild canids, and 10 outbred African shelter dogs across 60,968 single-nucleotide polymorphisms (SNPs). Coupling this genomic resource with external measurements from breed standards and individuals as well as skeletal measurements from museum specimens, we identify 51 regions of the dog genome associated with phenotypic variation among breeds in 57 traits. The complex traits include average breed body size and external body dimensions and cranial, dental, and long bone shape and size with and without allometric scaling. In contrast to the results from association mapping of quantitative traits in humans and domesticated plants, we find that across dog breeds, a small number of quantitative trait loci (< or = 3) explain the majority of phenotypic variation for most of the traits we studied. In addition, many genomic regions show signatures of recent selection, with most of the highly differentiated regions being associated with breed-defining traits such as body size, coat characteristics, and ear floppiness. Our results demonstrate the efficacy of mapping multiple traits in the domestic dog using a database of genotyped individuals and highlight the important role human-directed selection has played in altering the genetic architecture of key traits in this important species.

Domestication shapes morphology in rainbow trout Oncorhynchus mykiss.

In this study, clonal lines from North American resident and migratory populations of rainbow trout Oncorhynchus mykiss adapted to different geographical conditions and with different domestication histories were characterized morphologically. Lines reared in a common-garden experiment were characterized for external shape and meristic values, searching for a general pattern of morphological variation due to exposure to captive conditions. A sharp distinction was identified between wild and captive lines. The body profile was deeper in captive lines, with longer dorsal and anal fins and shorter and deeper caudal peduncles. Highly significant differences were also identified in meristic values among the lines but no consistent relation between meristic values and domestication status was detected. This morphological characterization will facilitate the selection of lines with divergent phenotypes for subsequent quantitative trait loci analysis, aimed at identifying genome regions linked with morphological adaptive response to captive conditions.

Examination of the anterior uveoscleral pathway in domestic species.

OBJECTIVE: To investigate the uveoscleral (US) pathway in the normal eyes of four domestic spp.: the cat, pig, cow and horse by examining the comparative anatomical structure of anterior US pathway. ANIMALS STUDIED: Four cats, ten pigs, four cows, eight horses. PROCEDURES: Formalin-preserved specimens from anterior uveas of the cat, pig, cow and horse were embedded and serially sectioned sagittally and tangentially and stained with H&E, Masson's trichrome, smooth muscle actin immunolabel, or elastin stain. RESULTS: Spaces between the endings of the outer anterior ciliary body musculature (CBM) formed avenues for the beginning of the US pathway and varied in the amount of extracellular matrix (ECM) material being most developed in the pig. In the cow, other anterior muscle bundles attached the CBM to the sclera concomitant with the presence of an anterior elastic sheath. In the horse, these muscle bundles were connected to branching connective tissue trabeculae within the US pathway that were attached radially to the sclera. In the cat, muscle bundles were more abundant and formed a fine meshwork of trabecular associations with the posterior ICA. Supraciliary development was most pronounced in the horse and least in the pig. CONCLUSION: All species possessed clearly developed and unique US pathways. The outermost muscle bundles of the CBM appeared to have close interaction with the US pathway and the degree of these muscle associations differed with species. The species specific anatomical variations within the US pathway could play a pivotal role in the variability of aqueous outflow along this pathway.

Comparison of area 17 cellular composition in laboratory and wild-caught rats including diurnal and nocturnal species.

In this study we examine the size of primary sensory areas in the neocortex and the cellular composition of area 17/V1 in three rodent groups: laboratory nocturnal Norway rats (Long-Evans; Rattus norvegicus), wild-caught nocturnal Norway rats (R. norvegicus), and laboratory diurnal Nile grass rats (Arvicanthis niloticus). Specifically, we used areal measures of myeloarchitecture of the primary sensory areas to compare area size and the isotropic fractionator method to estimate the number of neurons and nonneurons in area 17 in each species. Our results demonstrate that the percentage of cortex devoted to area 17 is significantly greater and the percentage of cortex devoted to S1 is significantly smaller in the diurnal Nile grass rat compared with the nocturnal Norway rat groups. Further, the laboratory rodent groups have a greater percentage of cortex devoted to auditory cortex compared with the wild-caught group. We also demonstrate that wild-caught rats have a greater density of neurons in area 17 compared to laboratory-reared animals. However, there were no other clear cellular composition differences in area 17 or differences in the percentage of brain weight devoted to area 17 between nocturnal and diurnal rats. Thus, there are differences in primary sensory area size between diurnal versus nocturnal and laboratory versus wild-caught rat groups and cellular density between wild-caught and laboratory rat groups. Our results demonstrate that the differences in the size and cellular composition of cortical areas do not fit with what would be expected based on brain scaling differences alone, and have a consistent relationship with lifestyle and sensory morphology.

Genetic architecture of tameness in a rat model of animal domestication.

A common feature of domestic animals is tameness-i.e., they tolerate and are unafraid of human presence and handling. To gain insight into the genetic basis of tameness and aggression, we studied an intercross between two lines of rats (Rattus norvegicus) selected over >60 generations for increased tameness and increased aggression against humans, respectively. We measured 45 traits, including tameness and aggression, anxiety-related traits, organ weights, and levels of serum components in >700 rats from an intercross population. Using 201 genetic markers, we identified two significant quantitative trait loci (QTL) for tameness. These loci overlap with QTL for adrenal gland weight and for anxiety-related traits and are part of a five-locus epistatic network influencing tameness. An additional QTL influences the occurrence of white coat spots, but shows no significant effect on tameness. The loci described here are important starting points for finding the genes that cause tameness in these rats and potentially in domestic animals in general.

Identification of working reindeer using palaeopathology and entheseal changes.

OBJECTIVE: This paper explores the potential of analyzing pathological lesions and entheseal changes in the identification of working reindeer. METHODS: The skeletons of 26 modern working reindeer from Siberia and Northern Finland are analyzed for pathological lesions and entheseal changes. RESULTS: Working results in elevated frequencies of pathological lesions, specifically joint disease in cervical and thoracic vertebrae, humeri, os coxae and proximal phalanges. Entheseal scores indicate the intensified use of shoulder flexors and extensors, and possibly elbow, hip and knee flexors and extensors in working reindeer. CONCLUSION: Patterns of skeletal changes can be used in the identification of working reindeer from the past. SIGNIFICANCE: This study provides first evidence that pathological lesions and entheseal changes can be used to assess draught and cargo use of reindeer. Therefore, the methods presented in this study provide an opportunity to scrutinize past reindeer herding practices, reindeer domestication and human-reindeer cooperation. LIMITATIONS: Methods need to be applied with caution due to the multifactorial etiologies of pathological lesions and entheseal changes. SUGGESTIONS FOR FUTURE RESEARCH: We suggest that in future studies, these methods are applied to archaeological material accompanied by osteometric and contextual analyses.

Genome-wide association analysis in domestic animals: a powerful approach for genetic dissection of trait loci.

Domestic animals have a sufficiently old history (thousands of generations) to allow evolution of phenotypes, but also a sufficiently young history (approximately 10,000 years) to allow powerful genetic dissection of phenotypic diversity. Domestic animals are therefore a unique resource for exploring genotype-phenotype relationships. Quantitative Trait Locus (QTL) mapping has been very successful in domestic animals but the identification of Quantitative Trait Mutations (QTMs) has been hard although a few prominent success histories have been reported. Genome-wide association analysis is now emerging as a powerful method for high-resolution mapping of loci controlling phenotypic traits in domestic animals. In two recent proof-of-principle studies we have used this approach to identify the mutations underlying two monogenic trait loci in dogs, white spotting and the hair ridge in Ridgeback dogs. In each case, we used only about 10 cases and 10 controls and mapped the locus to a region of about one mega base pair. In both cases the underlying mutations were non-coding underscoring the significance of regulatory mutations as a source for phenotypic diversity. Furthermore, we were able to shed light on the evolution of the allelic series at the white spotting (S) locus in dogs which encodes the microphthalmia-associated transcription factor (MITF). Our data showed that the three variant alleles described at this locus (Irish spotting, piebald and extreme white) do not represent three independent mutations but rather different combinations of a set of regulatory mutations affecting MITF expression. This is an excellent illustration of how the characterization of alleles selected during animal domestication contributes to an improved understanding of genotype-phenotype relationships.

Prehistoric domestication of animals: effects on bone structure.

Analytical techniques more usually applied in mineralogy have revealed consistent structural differences between the bones of wild and domestic animals from archeological deposits.

The initial domestication of goats (Capra hircus) in the Zagros mountains 10,000 years ago.

Initial goat domestication is documented in the highlands of western Iran at 10,000 calibrated calendar years ago. Metrical analyses of patterns of sexual dimorphism in modern wild goat skeletons (Capra hircus aegagrus) allow sex-specific age curves to be computed for archaeofaunal assemblages. A distinct shift to selective harvesting of subadult males marks initial human management and the transition from hunting to herding of the species. Direct accelerator mass spectrometry radiocarbon dates on skeletal elements provide a tight temporal context for the transition.

Factors that alter rumen microbial ecology.

Ruminant animals and ruminal microorganisms have a symbiotic relationship that facilitates fiber digestion, but domestic ruminants in developed countries are often fed an abundance of grain and little fiber. When ruminants are fed fiber-deficient rations, physiological mechanisms of homeostasis are disrupted, ruminal pH declines, microbial ecology is altered, and the animal becomes more susceptible to metabolic disorders and, in some cases, infectious disease. Some disorders can be counteracted by feed additives (for example, antibiotics and buffers), but these additives can alter the composition of the ruminal ecosystem even further.

The dynamic transfer of 3H and 14C in mammals: a proposed generic model.

Associated with the present debate regarding the potential revival of nuclear energy there is an increased interest in assessing the radiological risk to the public and also the environment. Tritium and (14)C are key radionuclides of interest in many circumstances (e.g. heavy water reactors, waste storage and fusion reactors). Because the stable analogues of these two radionuclides are integral to most biological compounds, their modelling should follow general principles from life sciences. In this paper, a model of the dynamics of (14)C and (3)H in mammals is proposed on the basis of metabolic understanding and of, as far as possible, readily available data (e.g. for organ composition and metabolism). The model is described together with validation tests (without calibration) for a range of farm animals. Despite simplifications, the model tests are encouraging for a range of animal types and products (tissues and milk), and further improvements are suggested.

Providing an intelligible explanation to pet owners by using three-dimensional CT images: use of clinical imaging for better informed consent.

The purpose of the study reported here was to discuss the level of intelligibility of three-dimensional computed tomography (3D-CT) images of clinical patients for persons who are lacking veterinary knowledge. 143 undergraduate students were participated in this study. They were entirely unfamiliar with veterinary anatomy. A survey was conducted using the visual analog scale method with a focus on the level of intelligibility of the 3D-CT images compared to that of the two-dimensional CT images or radiographs. As a result, the mean value of the intelligibility of the 3D-CT image was 88.4 +/- 17.8 points out of 100 points. In clinical cases, it is very difficult for pet owners lacking veterinary knowledge to understand the clinical status of their pets even with explanations using illustrations, radiographs, and transverse CT images. It is considered that better informed consent and patient satisfaction will be obtained provided veterinarians make an effort towards intelligible patient education by using 3D-CT images.

Muscle and fat mass modulation in different clinical models.

Studies described in the recent literature support the idea that gene therapy can lead to genuine clinical benefits when mediated by plasmid delivery in conjunction with electroporation. Plasmid-mediated muscle-targeted gene transfer offers the potential of a cost-effective pharmaceutical-grade therapy delivered by simple intramuscular injection. This approach is particularly appropriate for modulating muscle and fat mass and their intrinsic properties, from treatment of conditions such as cachexia associated with chronic diseases, autoimmune diseases, e.g., myasthenia gravis, to stimulation or suppression of appetite, and further to in vivo manipulation of glucose metabolism and fat deposition in patients with diabetes, or to basic studies of muscle-specific transcription factors and their impact in development. Recent innovations, including in situ electroporation, enabling sustained systemic protein delivery within the therapeutic range, are reviewed. Translation of these advances to human clinical trials will enable muscle- and fat-targeted gene therapy to become a viable therapeutic alternative.

Facilitating appreciation of anatomical variation and development of teamwork skills in the gross anatomy laboratory using a cadaver reassignment system.

Developing a mental map of the body in three dimensions incorporating normal anatomical variations is a challenge for students of gross anatomy. Acquisition of this ability is facilitated by frequently reassigning students to work on different specimens in gross anatomy laboratories, a significant departure from traditional teaching strategies. This article analyzes student and faculty experiences with a reassignment system over a six-year period, including effects on early professional development and students' attitudes toward the cadavers. Students were strongly supportive of the method, noting that specimen reassignments facilitated learning, encouraged dissection skill building, and fostered collaborative interactions. Students' perception of the value of the contribution of each cadaver to their education was preserved and, for many, enhanced. Frequent specimen reassignments offer an opportunity to model public accountability for work and some aspects of the relationships between multiple health care teams caring for a patient.