Authors : Zaabouti Najla, Mounir Nafti, Zahran Khaldi and Sami Souid
Abstract: This study investigated genetic polymorphisms in the local goat populations of Tunisia. The polymorphisms of the β-lactoglobulin (β-LG) and kappa casein (CNS3) genes of two goat subpopulations in southern Tunisia (Jerid and Nefzawa regions), known as Arbi and Serti, were assessed at the DNA level. The DNA of 151 individual goats for β-LG and 171 individuals for CNS3 were extracted and then genotyped for β-LG using restriction fragment length polymorphism; SmaI restriction enzyme technique; and HaeIII restriction enzyme technique for CNS3. CNS3 gene digestion revealed two fragments of different sizes, 416 bp and 229 bp, indicating the presence of the AA and AB genotypes of kappa casein in the population. The AB genotype (645/416/229 bp) was also detected, while the BB genotype was completely absent in the oasis goat population. The results of the β-LG gene revealed three different genotypes, each characterized by a different number and size of fragments. The homozygous form CC presented three fragments of different sizes, 472, 181 and 50 bp, while the other form TT presented only two fragments, 472 and 231 bp. Finally, the heterozygous form CT controlled four fragments of different sizes, 472, 231, 181 and 50 bp. Allele A of kappa-casein occurred at a higher frequency than allele B in both the Arbi and Serti subpopulations and the overall population. The β-lactoglobulin C allele was more common than the T allele in the Arbi and Serti subpopulations and throughout the population. The genotypic frequencies of homozygotes were found to be higher than those of heterozygotes in the two subgroups and within the total population. At the CNS3 locus, the total population and the two subpopulations (Arbi and Serti) were in Hardy- Weinberg equilibrium, while deviation from Hardy- Weinberg equilibrium was recorded at the β-LG locus.
Zaabouti Najla, Mounir Nafti, Zahran Khaldi and Sami Souid, 2022. Polymorphism of Beta-Lactoglobulin and Kappa Casein Genes in Tunisian Native Goats. Journal of Animal and Veterinary Advances, 21: 25-33.