Le polymorphisme des protéines sanguines chez le dromadaire (<em>Camelus dromedarius</em>) au Maroc

Deux cent dix-sept sérums et 117 hémolysats de dromadaires du Maroc (Camelus dromedarius) ont été analysés respectivement par électrophorèse en gel de polyacrylamide pour trois systèmes, l'albumine (Alb), la post-albumine (Pa) et la transferrine (Tf) et par électrophorèse en gel d'amidon pour le système catalase (Cat). Seul ce dernier système a montré une variation génétique avec des fréquences respectives de 0,325 et 0,675 pour les allèles CatF et CatS

Genetic analysis and phylogenetic relationships of the Barb horse through the use of microsatellites

The aim of this study was to compare genetically Moroccan (MA) and Tunisian (TN) Barb horses and toe stablish the phylogenic relation between Barb horse and other horse breeds in Morocco by using microsatellites. First, 100 Moroccan barb and 100 Tunisian Barb horses were used. Genetic variability index between and inside the populations were estimated. 133 alleles were detected in the Moroccan population and 125 in the Tunisian. The mean number of alleles was 7.29 and 7.82 respectively for the Tunisian and Moroccan barb horse. The heterozygosity was almost similar in the two groups of Barb horses (TN = 0.716 and MA = 0.714). Fst was estimated at 0.0454 and 0.0780 respectively for TN and MA Barb horses. The Gst was also estimated at 0.012 and the Nei genetic distance at 0.05. The two populations are almost genetically similar and heterogeneous. Finally, 86,5 % of horses were correctly affected to their likelihood population. Secondly, 50 Arabian horses, 50 Arabian-Barb and 50 thoroughbreds and the 200 Barb horses previously studied were used to establish the phylogenic relationships. The use of 17 microsatellites showed that the Barb horses had specific alleles and the highest heterozygosity and the highest genetic distances were obtained with thoroughbred. The two Barb horse populations were highly combined in one side of the phylogenic tree

Analyse génétique et relations phylogénétiques du cheval Barbe par l’utilisation des microsatellites

The aim of this study was to compare genetically Moroccan (MA) and Tunisian (TN) Barb horses and toe stablish the phylogenic relation between Barb horse and other horse breeds in Morocco by using microsatellites. First, 100 Moroccan barb and 100 Tunisian Barb horses were used. Genetic variability index between and inside the populations were estimated. 133 alleles were detected in the Moroccan population and 125 in the Tunisian. The mean number of alleles was 7.29 and 7.82 respectively for the Tunisian and Moroccan barb horse. The heterozygosity was almost similar in the two groups of Barb horses (TN = 0.716 and MA = 0.714). Fst was estimated at 0.0454 and 0.0780 respectively for TN and MA Barb horses. The Gst was also estimated at 0.012 and the Nei genetic distance at 0.05. The two populations are almost genetically similar and heterogeneous. Finally, 86,5 % of horses were correctly affected to their likelihood population. Secondly, 50 Arabian horses, 50 Arabian-Barb and 50 thoroughbreds and the 200 Barb horses previously studied were used to establish the phylogenic relationships. The use of 17 microsatellites showed that the Barb horses had specific alleles and the highest heterozygosity and the highest genetic distances were obtained with thoroughbred. The two Barb horse populations were highly combined in one side of the phylogenic tree. Key words: horse, barb, genetic analysis, microsatellites, genetic index, phylogenic treeCe travail s’est intéressé à la comparaison génétique entre les chevaux Barbes du Maroc et de Tunisie et à l’établissement des relations phylogénétiques entre le cheval Barbe et les autres races de chevaux existantes au Maroc par l’utilisation des microsatellites. Premièrement, 100 chevaux barbes marocains et 100 tunisiens ont été utilisés et les indices de la variabilité intra et inter-population ont été évalués. 133 allèles ont été détectés pour le Barbe marocain contre 125 pour le tunisien. Le NMA était de 7,29 et 7,82 respectivement chez le Barbe tunisien et marocain. Les taux d’hétérozygotie moyens étaient presque similaires chez les deux populations. Le Fst était de 0,0454 et 0,0780 respectivement chez le Barbe de Tunisie et du Maroc. Le Gst était très faible et la distance génétique de Nei était de 0,05. Les deux populations sont donc hétérogènes et pratiquement identiques. 86,5% des individus étudiés ont été affecté convenablement à leur population d’origine. Deuxièmement, 50 chevaux Arabe, 50 Arabe-Barbe et 50 Pur-Sang, en plus des 200 chevaux Barbes préalablement étudiés ont été utilisés. Le cheval barbe a présenté des allèles spécifiques et une forte hétérozygotie avec une distance génétique maximale avec le Pur-Sang. L’arbre phylogénétique a montré, un regroupement très significatif entre les deux populations Barbes d’un côté et les trois autres races de l’autre. Mots clés : cheval, Barbe, analyse génétique, microsatellites, indices de variabilité génétique, arbre phylogénétiqu

Etude épidémiologique de la rhinopneumonie chez les équidés au Maroc

Lors d'une enquête sérologique sur la rhinopneumonie équine au Maroc, 4 775 prélèvements (59,6 % de chevaux, 18 % de mulets et 22,4 % d'ânes) ont été réalisés durant cinq ans (de 1990 à 1994) dans les différentes régions du pays. La séroprévalence globale de l'infection était de 39 %. Les ânes (46 %) étaient plus affectés que les mulets (42 %) et les chevaux (35 %). En outre, chez les trois espèces, la séroprévalence a augmenté avec l'âge jusqu'à trois ans pour atteindre la valeur de 42 % et elle s'est stabilisée pour les animaux plus âgés. Il n'est pas certain que le sexe et la région géographique où vivaient les animaux les prédisposaient à la maladie. Par contre, leurs conditions d'entretien ont constitué un facteur prédisposant à l'infection. Après une stabilisation pendant les quatre premières années, l'incidence de l'infection s'est subitement accrue en 1994 à cause de la sécheresse qui a sévi cette année-là

Major inconsistencies of inferred population genetic structure estimated in a large set of domestic horse breeds using microsatellites

STRUCTURE remains the most applied software aimed at recovering the true, but unknown, population structure from microsatellite or other genetic markers. About 30% of structure-based studies could not be reproduced (Molecular Ecology, 21, 2012, 4925). Here we use a large set of data from 2,323 horses from 93 domestic breeds plus the Przewalski horse, typed at 15 microsatellites, to evaluate how program settings impact the estimation of the optimal number of population clusters Kopt that best describe the observed data. Domestic horses are suited as a test case as there is extensive background knowledge on the history of many breeds and extensive phylogenetic analyses. Different methods based on different genetic assumptions and statistical procedures (dapc, flock, PCoA, and structure with different run scenarios) all revealed general, broad-scale breed relationships that largely reflect known breed histories but diverged how they characterized small-scale patterns. structure failed to consistently identify Kopt using the most widespread approach, the ΔK method, despite very large numbers of MCMC iterations (3,000,000) and replicates (100). The interpretation of breed structure over increasing numbers of K, without assuming a Kopt, was consistent with known breed histories. The over-reliance on Kopt should be replaced by a qualitative description of clustering over increasing K, which is scientifically more honest and has the advantage of being much faster and less computer intensive as lower numbers of MCMC iterations and repetitions suffice for stable results. Very large data sets are highly challenging for cluster analyses, especially when populations with complex genetic histories are investigated.info:eu-repo/semantics/publishedVersio

Genetic diversity of the semi-feral Marismeño horse breed assessed with microsatellites

Marismeño horses originated from primitive horses living around the marshes of the Guadalquivir River in Southern Spain. Throughout their evolution, they have experienced crosses with other breeds, first with horses from North Africa and thereafter with other horses. However, they have not lost their ability to adapt to the demanding marsh environment. Recently, a studbook of the breed was established, and the Breeders Association started a conservation programme. To study the relationship of the Marismeño with other breeds, a microsatellite analysis was developed, which included other ancient Southern Iberian horse populations, such as the Sorraia and Retuertas breeds. Candidates of recent crossbreeding with Marismeño horses, such as the Hispano-Arabian and the Spanish Purebred, were studied, and the Thoroughbred and the Arabian breed were used as international references. The results indicated that the Marismeño horse population maintains a great genetic diversity. Despite recent crossbreeding, the fixation index and the Hardy-Weinberg equilibrium analysis disclosed a certain homogeneity degree. A dendrogram was built using the obtained genetic distances, and clustering was performed with the software STRUCTURE, and the results reflected the genetic differentiation of the Marismeño horse from the other autochthonous Iberian breeds, although the Marismeño population has maintained a tight relationship with the Spanish Purebred. Remarkably, some relatedness between the Marismeño and the Barb horse breeds could be observed and was most likely derived from an ancient gene flow between the horses of the Iberian Peninsula and North Africa