Unravelling the hybrid vigor in domestic equids: the effect of hybridization on bone shape variation and covariation

Hybridization has been widely practiced in plant and animal breeding as a means to enhance the quality and fitness of the organisms. In domestic equids, this hybrid vigor takes the form of improved physical and physiological characteristics, notably for strength or endurance. Because the offspring of horse and donkey is generally sterile, this widely recognized vigor is expressed in the first generation (F1). However, in the absence of recombination between the two parental genomes, F1 hybrids can be expected to be phenotypically intermediate between their parents which could potentially restrict the possibilities of an increase in overall fitness. In this study, we examine the morphology of the main limb bones of domestic horses, donkeys and their hybrids to investigate the phenotypic impact of hybridization on the locomotor system. We explore bone shape variation and covariation to gain insights into the morphological and functional expressions of the hybrid vigor commonly described in domestic equids

Quand, dans le premier tiers du XIe siècle, le peuple cordouan s'emparait de la rue…

This is a study of the common people of Cordova as represented in the Bayān for the years 1002-1031. They are the Cordovans excluded from power: the ‛āmma and the middle class. This group, variously named, includes those involved in trade, from shopkeepers and artisans in the market to prominent merchants (tuǧǧār). The people, dominated by the authorities, play a passive role in Cordovan life; they witness public events and support the the authorities when asked. But they can also take control of the public sphere, both by their vox populi and by violence; then power in the urban areas is inverted, and the authorities no longer control the public arena.El pueblo de Córdoba, estudiado aquí a partir del Bayān, entre los años 1002 y 1031, se sitúa como el grupo de cordobeses excluidos del poder, es decir, la ‛āmma y la clase media. Este grupo, designado por varias denominaciones, comprende a los comerciantes, desde la gente del zoco (tenderos y pequeños artesanos) hasta la capa importante de los mercaderes (tŷŷār). El pueblo está bajo el dominio del poder y aparece como actor pasivo de la vida cordobesa: asiste al espectáculo de la calle, aprueba al poder cuando se le pide. Sin embargo, tiene capacidad para apoderarse de la calle, mediante la vox populi, pero también mediante el tumulto, lo que conduce a invertir el dominio de los espacios urbanos, pues entonces el espacio público se le escapa de las manos al poder

Cranial shape diversification in horses: variation and covariation patterns under the impact of artificial selection

The potential of artificial selection to dramatically impact phenotypic diversity is well known. Large-scale morphological changes in domestic species, emerging over short timescales, offer an accelerated perspective on evolutionary processes. The domestic horse (Equus caballus) provides a striking example of rapid evolution, with major changes in morphology and size likely stemming from artificial selection. However, the microevolutionary mechanisms allowing to generate this variation in a short time interval remain little known. Here, we use 3D geometric morphometrics to quantify skull morphological diversity in the horse, and investigate modularity and integration patterns to understand how morphological associations contribute to cranial evolvability in this taxon. We find that changes in the magnitude of cranial integration contribute to the diversification of the skull morphology in horse breeds. Our results demonstrate that a conserved pattern of modularity does not constrain large-scale morphological variations in horses and that artificial selection has impacted mechanisms underlying phenotypic diversity to facilitate rapid shape changes. More broadly, this study demonstrates that studying microevolutionary processes in domestic species produces important insights into extant phenotypic diversity.Introduction Material and methods - Material - Acquisition of data - Shape analyses - Integration and modularity -- Modular patterning -- Covariation patterns -- Magnitude of morphological integration Results - Size and shape variation - Allometry‑free shape variation - Allometry‑free shape variation of the modules - Modularity and integration Discussion - Cranial shape variation in the horse: the role of allometry and artificial selection in the morphological diversification - Cranial modularity and shape diversification -- Stasis in patterns, changes in magnitude -- Influence of morphological integration on shape variance - The role of function and development in integration patterns -- Anterior region -- Posterior region Conclusio

Long-Term Quantitative Evaluation of Muscle and Bone Wasting Induced by Botulinum Toxin in Mice Using Microcomputed Tomography

Muscle and bone masses are highly correlated and muscles impose large loads on bone. Muscle wasting that accompanies bone loss has been poorly investigated. 21 female mice were spread into seven groups. At day 0, 18 mice received Botulinum toxin (BTX) injection in the quadriceps muscle to induce paralysis of the right hind limb; the left contralateral side was used as control. Mice were sacrificed at 7, 14, 21, 28, 56 and 90 days post-injection. A remaining group was sacrificed at day 0. Trabecular bone volume was determined by microcomputed tomography (microCT) at the distal femur and tibia proximal metaphyses on both sides. Limbs were immersed in an HgCl solution allowing muscle visualization by microCT. On 2D sections, the cross-sectional areas and form-factors were measured for the quadriceps at mid-thigh and gastrocnemius at mid-leg and these muscles were dissected and weighed. Bone volume decreased in the paralysed side. Bone loss was maximal at 56 days followed by recuperation at 90 days. The cross-sectional areas of gastrocnemius and quadriceps were significantly lower in the paralysed limb from 7 days; the decrease was maximum at 21 days for the gastrocnemius and 28 days for the quadriceps. No difference in form-factors was found between the two limbs. Similar results were obtained with the anatomical method and significant correlations were obtained between the two methods. Quantitative analysis of muscle loss and recovery was possible by microCT after using a metallic contrast agent. Loss of bone secondary to muscle wastage induced by BTX and recovery showed a parallel evolution for bone and muscles

Étude ostéo-biométrique de la « race » cameline algérienne Sahraoui (Camelus dromedarius L., 1758)

International audienceThis study was realized on a sample of 60 dromedaries of Sahraoui breedfrom the south of Algeria. The animals, 30 males and 30 females, are adultsover 6 years destined for slaughter. Before slaughter in Ouargla abattoir,measurements during their life-time were performed (3 parameters).Carcass weight was recovered at the slaughter house. The canon bonesor metapodials were taken (one left metacarpus and metatarsus of eachanimal), were weighed and measured after cooking and drying (16 variablesper animal), gracility index of bones were calculated (6 indexes per animal).The variability and correlations between variables were analyzed and allowwhile realizing a referential of archeozoology, to consider the ability tograsp certain parameters of live animal from bone measurements. Linearregression equations were proposed in order to estimate the animal’s liveweight, and its height at the withers from the best correlated measurements.A multivariate function (logistic regression) from seven linear parametersof each metapodial was calculated, it permits to envisage sexing from anisolated bone. Sexual dimorphism appears clearly at the level of metapodial:the males have canon bones which are not only larger and stockier but alsolonger which is a remarkable difference in comparison to those encounteredin other ruminants like cattle or sheep for which the great length of bone isnot a dimorphic parameter.Cette étude a été réalisée sur un échantillon de 60 dromadaires du sudalgérien, de race Sahraoui. Les animaux, 30 mâles et 30 femelles, sontdes adultes de plus de 6 ans destinés à la boucherie. Préalablement à leurabattage, à l’abattoir de Ouargla, des prises de mensurations de leur vivantont été réalisées (3 paramètres). Le poids de carcasse a ensuite été noté àl’abattoir. Les os canons, ou métapodes, ont été prélevés (un métacarpe etun métatarse gauches pour chaque animal) puis pesés et mesurés aprèscuisson et séchage (16 variables par animal). Des indices de gracilité desos ont été calculés (6 indices par animal). La variabilité et les corrélationsentre variables ont été analysées et permettent, notamment dans le cadre dela réalisation de référentiels pour l’archéozoologie, d’envisager de pouvoirappréhender certains paramètres de l’animal sur pied, à partir des mesuresdes os. Des équations de régression linéaire ont été proposées afin d’estimerle poids vif de l’animal et sa hauteur au garrot, à partir des mensurations lesmieux corrélées. Une fonction multivariée (régression logistique) à partirdes sept paramètres linéaires de chacun des métapodes a été calculée ; ellepermet d’envisager de sexer un os isolé. Le dimorphisme sexuel apparaît,en effet, au niveau du métapode de façon nette : les mâles ont des os canonnon seulement plus gros et plus trapus, mais aussi plus longs, ce qui est unedifférence notable par rapport à ce que l’on rencontre chez d’autres ruminantscomme les bovins ou les moutons pour lesquels la grande longueur de l’osn’est pas un paramètre dimorphique

Comparative anatomical study of sound production and reception systems in the common dolphin ( Delphinus delphis ) and the harbour porpoise ( Phocoena phocoena ) heads

International audienceMagnetic resonance imaging (MRI) and computed tomography (CT) scans were used to analyse, respectively, the soft tissues and the bones of the heads of four common dolphins and three harbour porpoises. This imaging study was completed by an examination of anatomical sections performed on two odontocete heads (a subadult common dolphin and a subadult harbour porpoise). The three complementary approaches allowed to illustrate anatomical differences in the echolocation systems of the common dolphin and the harbour porpoise. We captured images confirming strong differences of symmetry of the melon and of its connexions to the MLDB (Monkeys Lips/Dorsal Bursae) between the common dolphin and the harbour porpoise. The melon of the common dolphin is asymmetrically directly connected to the right bursae cantantes at its right side, whereas the melon of the harbour porpoise is symmetrical, and separated from the two bursae cantantes by a set of connective tissues. Another striking difference comes from the bursae cantantes themselves, less deeply located in the head of the common dolphin than in the harbour porpoise

Cranial shape diversification in horses: variation and covariation patterns under the impact of artificial selection

The potential of artificial selection to dramatically impact phenotypic diversity is well known. Large-scale morphological changes in domestic species, emerging over short timescales, offer an accelerated perspective on evolutionary processes. The domestic horse (Equus caballus) provides a striking example of rapid evolution, with major changes in morphology and size likely stemming from artificial selection. However, the microevolutionary mechanisms allowing to generate this variation in a short time interval remain little known. Here, we use 3D geometric morphometrics to quantify skull morphological diversity in the horse, and investigate modularity and integration patterns to understand how morphological associations contribute to cranial evolvability in this taxon. We find that changes in the magnitude of cranial integration contribute to the diversification of the skull morphology in horse breeds. Our results demonstrate that a conserved pattern of modularity does not constrain large-scale morphological variations in horses and that artificial selection has impacted mechanisms underlying phenotypic diversity to facilitate rapid shape changes. More broadly, this study demonstrates that studying microevolutionary processes in domestic species produces important insights into extant phenotypic diversity