Genetic polymorphism study of the Tunisian Barbarine breed
2014
Ressaissi, Y | Bedhiaf-Romdhani, S
Tunisia is well endowed with a wealth of native sheep breeds. The Barbarine, also called “Nejdi”or “Arbi”, remains the main Tunisian sheep breed and it is raised in all regions with an abundance in the central region (43.3%). Although this breed has benefited from a programme of monitoring of performances for quite a long time, its productivity remains low. Thus its genetic management requires more attention. In this context the objectives of this study were to determine the genetic polymorphism in the Barbarine breed of the central region of Tunisia and to calculate genetic distances between genotyped animals. The genomic DNA of 24 purebreds Barbarine individual was extracted. These animals belong to the Tunisian Public Lands’s Office (OTD) herds which are located in the governorates of Kairouan and Sidi Bouzid (centre of Tunisia). These samples were amplified by the PCR using four microsatellite molecular markers. Genotyping analysis was per- formed by Bio-Capt, NTSYSpc and GENAlex6.2 softwares. The value of the PIC was 0.92, showing the effec- tiveness of the use of the microsatellite markers in the diversity analysis. The genetic diversity’s study has detected an average number of 11 alleles per locus. The allele frequencies were close and all loci were in dis- equilibrium compared to the act of Hardy-Weinberg equilibrium. The values of the observed heterozygosis (Ho) and the expected heterozygosis (He) were 0.23 and 0.88 respectively. Based on multi loci, the unbiased het- erozygosis was 0.86 and was greater than the observed heterozygosis (0.12). The fixation index found, which reflects the deviation of the observed heterozygosity and the expected one, was positive in the range of 0.85 explaining an heterozygosis deficiency in the studied population. This means that the structure of these two farms showed an increased homogeneity between herds and management of genealogies in the mating strat- egy seems to be missing in the Tunisian central region, which could lead to a loss of genes.
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