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 (PrP) of the cellular prion protein (PrP). The susceptibility of sheep to scrapie is influenced by polymorphisms in the gene (PRNP). The aim of this study was to identify the genetic variability of sheep 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 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 variability in Algerian sheep and may serve as a basis for the development of breeding programmes to render national sheep breeds resistant to scrapie.
Due to the absence of the ethnic data and studies of racial characterizations of this species in Algeria, which is an endangered species, we contributed to the phenotypical study of donkey population in the area of Tlemcen. A manpower of 61 adult asses, distributed on the level of two areas from where 11 body measurements and 06 phenotypical characters were retained for this study. Measurements LTC, HG, TP, LH, LE, PC, LoT, LoO, LQ, LaT and TM are respectively of 157,26±12,88; 116,16±7,23; 124,26±7,03; 37,15±3,21; 27,07±3,27; 17,50±1,86; 52,39±4,06; 30,15±2,19; 41,42±5,76; 23,01±2,06 and 46,24±4,16cm. the sex does not present any significant effect on studied body measurements (p>0,05). A factorial analysis of the multiple correspondences was carried out on the phenotypical characteristics, and it revealed two principal components which constitute 47,62% and 41,39% of total inertia, percentages respectively related to the color of the dress, the head, the members, the hairs, the muzzle and the belly .This analysis made it possible to establish remarkable phenotypical differences which have implications to take into account in the program of characterization and conservation of the species.
The richness of the variability of the sheep genetic resources is untapped. We have noted the presence of 12 sheep breeds in Algeria such as Ouled Djellal, Rembi, Hamra, Berber, Barbarine, D'man, Sidaou, Tadmit, Tazegzawt, Ifilene, Srandi and Daraa, which are well adapted to the conditions of the environments. Unfortunately, anarchic crossings lead to dispersion and an erosion of the genetic capital of the breeds, the increase of consanguinity in the herds and a decrease of the returns of the farms. The medium-term risk is the absorption of certain «breeds" by others, and the loss of certain characters that make the specificity of our breeds. In addition, the documentation on the diversity of sheep breeds in Algeria is minimal or absent, so several breeds require a phenotypic and zootechnical description to know their performance. This document describes the sheep genetic resources present in Algeria and the diversity between them based on surveys that have been carried out for more than 17 years, in 40 wilayas, based on the phenotypic characterization of these "breeds" in their cradles, in order to make an updated breed distribution map and a new breed classification.
To study of the biodiversity of the sheep genetic resources, our phenotypic approach consists on the barymetric parameters of Algerian sheep breeds in western Algeria using the body measurements in 166 sheep of six breeds: Ouled Djellal, Hamra, Barbarine, Srandi, Daraa and Tazegzawt. The body measurements studied are: WH, SIL, HG, CD, SW, RW, TW, PL, HL, HW, EL, EW and CP, they are respectively : 84.71±7.15 cm ; 84.08±7.96 cm 103.53±10.79 cm ; 30.21±4.18 cm ; 17.34±2.09 cm ; 21.63±2.90 cm ; 26.01±2.32 cm ; 24.40± 4.07 cm ; 25.58±1.99 cm ; 15.18±1.62 cm ; 16.22±2.60 cm ; 8.24±0.96cm et 9.09±1.21 cm. The barymetric characterization revealed clear barymetric diversity between the breeds studied and between males and females, with very highly significant differences (p<0.001) for the most of body measurements used. A principal component analysis (CPA) was performed on the barymetric characteristics, revealed two main principal components accounting for 55.63% and 18.02% of the inertia, being related to WH, HG, CD, TW and SIL. The results of the CPA allowed establishing 3 classes, which only one class presents the majority of the population.
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