RESUMEN
Cattle plays a very important role in agriculture and food security in Algeria. In the present study, the genetic diversity and structure of Algerian indigenous cattle populations were evaluated by microsatellite markers. A total of 138 individuals belonging to four cattle breed populations were characterized using 22 microsatellite markers. A total of 360 alleles was detected across studied all loci. Results obtained for the mean number of alleles (16.36), expected heterozygosity (0.84) and polymorphic information content (0.82) indicated that the total analyzed populations are characterized by noticeable genetic variability. It can be said that there is a low genetic differentiation in the cattle populations studied considering obtained mean FST value (0.039). It was revealed 97.10% of the total genetic variation can be explained by genetic differences among individuals while 2.90% among populations. The structure, factorial correspondence analysis results and dendrogram showed that cattle populations studied are clustered in three groups. The present study has revealed an important knowledge about the genetic diversity and the relationship between some native cattle breeds raised in Algeria. The results showed that the breeds studied have a high genetic diversity. Moreover, it can be said that microsatellite markers used can be successfully used to determine genetic diversity and population structure in Algerian cattle breeds.
Asunto(s)
Bovinos , Repeticiones de Microsatélite , Argelia , Animales , Cruzamiento , Bovinos/genética , Variación Genética , Genética de PoblaciónRESUMEN
This study was carried out in order to identify the body measurements of two different Dromedary camel breeds raised in Algeria. The animal material of the study consisted of a total of 115 animals belong to Steppe (n = 55) and Sahraoui (n = 60) camel breeds. Eye and coat colors along with body measurements such as head length, neck length, neck girth, tail length, distance between eyes, distance between ears, body length, withers height, chest girth, and live weight were determined. Least squares means for head length, neck length, neck girth, tail length, distance between eyes, distance between ears, body length, withers height, chest girth, and live weight are found 48.2, 116.9, 65.7, 55.6, 24.1, 22.5, 152.2, 184.5, 141.2 cm, and 217.2 kg for Steppe and 48.1, 101.2, 56.2, 51.2, 23.4, 18.3, 135.6, 167.3, 176.8 cm, and 298.9 kg for Sahraoui camel breeds, respectively. The distribution of brown and black eye colors for the Steppe camel breed is as 58.2% and 41.8%, respectively, while all of the Sahraoui camels studied had a brown eye color. The proportional distribution in terms of body color included are coffee, dark coffee, and red colors for 1.8%, 83.6%, and 14.6% in the Steppe camel and 98.3%, 1.7%, and 0.0% for the Sahraoui camel, respectively. As a result, this study concluded that the withers height and chest girth could estimate the body weight in the two breeds of camels with different ages.
Asunto(s)
Peso Corporal , Camelus/anatomía & histología , Camelus/genética , Cuello/anatomía & histología , Argelia , Animales , Análisis de los Mínimos Cuadrados , Modelos Biológicos , Análisis de RegresiónRESUMEN
Scrapie is a prion disease that affects the sheep and goats. It belongs to the group of transmissible spongiform encephalopathies (TSE). TSEs are characterized by the accumulation of the pathological form (PrPSc) of the cellular prion protein (PrPC). The susceptibility of sheep to scrapie is influenced by polymorphisms in the PrP gene (PRNP). The aim of this study was to identify the genetic variability of sheep PRNP in Algerian sheep. Two-hundred and thirteen Algerian sheep from eight breeds (Ouled Djellal, Rembi, Hamra, Berbere, Barbarine, Sidaou, Taadmit and Tazegzawt) with no clinical manifestation of scrapie were analysed. Sequencing of the entire coding sequence of PRNP showed four main alleles (ARQ, ARR, AHQ and ARH) based on codons 136, 154 and 171 with different frequencies among the investigated breeds. Moreover, 14 additional nonsynonymous polymorphisms (Q101R, N103K, M112T, A116P, M137I, L141F, I142M, H143R, N146S, R151G, Y172D, N176K, H180Y and S240P) as well as two synonymous polymorphisms at codons 231 and 237 were found in the PRNP gene. Interestingly, the N103K, M137I and I142M polymorphisms were not described in sheep. The ARQ, ARR and ARH haplotypes were present in all breeds with a highest frequency of ARQ in Barbarine. The ARH was absent in Barbarine breed and the VRQ haplotype was absent in all Algerian breeds studied. The ARQ and ARR alleles were the most common with frequencies ranging from 30 to 65% and from 8 to 26%, respectively, in different breeds. These results represent the first study on PRNP variability in Algerian sheep and may serve as a basis for the development of breeding programmes to render national sheep breeds resistant to scrapie.
Asunto(s)
Biodiversidad , Resistencia a la Enfermedad/genética , Scrapie/genética , Selección Genética , Enfermedades de las Ovejas/genética , Ovinos/genética , Argelia , Alelos , Animales , Cruzamiento , Frecuencia de los Genes , Haplotipos , Polimorfismo Genético , Proteínas Priónicas/genética , Análisis de Secuencia de ADN , Ovinos/clasificación , Ovinos/crecimiento & desarrollo , Especificidad de la EspecieRESUMEN
Algeria represents a reservoir of genetic diversity with local sheep breeds adapted to a large range of environments and showing specific features necessary to deal with harsh conditions. This remarkable diversity results from the traditional management of dryland by pastoralists over centuries. Most of these breeds are poorly productive, and the economic pressure leads farmers to realize anarchic cross-breeding (that is, not carried out in the framework of selection plans) with the hope to increase animal's conformation. In this study, eight of the nine local Algerian sheep breeds (D'men, Hamra, Ouled-Djellal, Rembi, Sidaoun, Tazegzawt, Berber and Barbarine) were investigated for the first time by genome-wide single-nucleotide polymorphism genotyping. At an international scale, Algerian sheep occupied an original position shaped by relations with African and European (particularly Italian) breeds. The strong genetic proximity with Caribbean and Brazilian breeds confirmed that the genetic make-up of these American breeds was largely influenced by the Atlantic slave trade. At a national scale, an alarming genetic dilution of the Berber (a primitive breed) and the Rembi was observed, as a consequence of uncontrolled mating practices with Ouled-Djellal. A similar, though less pronounced, phenomenon was also detected for the Barbarine, another ancestral breed. Genetic originality appeared to be better preserved in Tazegzawt, Hamra, D'men and Sidaoun. These breeds should be given high priority in the establishment of conservation plans to halt their progressive loss. For Berber and Barbarine that also occur in the bordering neighbor countries, urgent concerted transnational actions are needed.
Asunto(s)
Técnicas de Genotipaje , Polimorfismo de Nucleótido Simple , Oveja Doméstica/genética , Argelia , Animales , Teorema de Bayes , Cruzamiento , Modelos GenéticosRESUMEN
The objectives of this study were to characterize the genetic variability of village chickens from three agro-ecological regions of western Algeria: coastal (CT), inland plains (IP) and highlands (HL), to reveal any underlying population structure, and to evaluate potential genetic introgression from commercial lines into local populations. A set of 233 chickens was genotyped with a panel of 23 microsatellite markers. Geographical coordinates were individually recorded. Eight reference populations were included in the study to investigate potential gene flow: four highly selected commercial pure lines and four lines of French slow-growing chickens. Two populations of wild red jungle fowls were also genotyped to compare the range of diversity between domestic and wild fowls. A genetic diversity analysis was conducted both within and between populations. Multivariate redundancy analyses were performed to assess the relative influence of geographical location among Algerian ecotypes. The results showed a high genetic variability within the Algerian population, with 184 alleles and a mean number of 8.09 alleles per locus. The values of heterozygosity (He and Ho) ranged from 0.55 to 0.62 in Algerian ecotypes and were smaller than values found in Jungle fowl populations and higher than values found in commercial populations. Although the structuring analysis of genotypes did not reveal clear subpopulations within Algerian ecotypes, the supervised approach using geographical data showed a significant (p < 0.01) differentiation between the three ecotypes which was mainly due to altitude. Thus, the genetic diversity of Algerian ecotypes may be under the influence of two factors with contradictory effects: the geographical location and climatic conditions may induce some differentiation, whereas the high level of exchanges and gene flow may suppress it. Evidence of gene flow between commercial and Algerian local populations was observed, which may be due to unrecorded crossing with commercial chickens. Chicken ecotypes from western Algeria are characterized by a high genetic diversity and must be safeguarded as an important reservoir of genetic diversity.
Asunto(s)
Aves/genética , Pollos/genética , Variación Genética , Argelia , Animales , Aves/clasificación , Análisis por Conglomerados , Femenino , Masculino , Repeticiones de MicrosatéliteRESUMEN
In this study, genetic analyses of diversity and differentiation were performed on five horse breeds raised in Algeria (Barb, Arab-Barb, Arabian, Thoroughbred and French Trotter). All microsatellite markers were highly polymorphic in all the breeds. A total of 123 alleles from 14 microsatellite loci were detected in 201 horses. The average number of alleles per locus was the highest in the Arab-Barb horses (7.86) and lowest in the thoroughbred breed (5.71), whereas the observed and expected heterozygosities per breed ranged from 0.71 (Thoroughbred) to 0.752 (Barb) and 0.71 (Thoroughbred) to 0.77 (Arab-Barb), respectively. The genetic differentiation between the breeds was significant (p < 0.01) based on the infinitesimal model (FST ). Three different approaches for evaluating the genetic relationships were applied. Genetic distances, the factorial correspondence analysis and structure analysis showed that a significant amount of genetic variation is maintained in the native horse populations and the other breeds. The Barb and Arab-Barb breeds seem to be the most genetically related and support the decision to consider the breeds as same population.