Genetic polymorphism of casein alpha-S1 gene in Tunisian local Goat

The genetic polymorphism of the casein alpha-S1 locus wasinvestigated in Tunisian goat. Blood samples were collected from localgoat breed. Genomic DNA samples were obtained from leukocytes of75 dairy goats and regions of interest in the gene were amplifiedthrough Polymerase Chain Reaction (PCR), then evaluated in agarosegels. For better characterization of the single nucleotidepolymorphism, if exist, a PCR-Restriction Fragment LengthPolymorphism study was performed employing the endonucleaseXmnI. DNA amplification using primers produced fragments withsizes of 457 bp. The PCR products of primer (223 bp) digested byrestriction enzyme Xmn1 produced four fragments at 223 bp, 212bp,161bp and 150-bp. The results showed that local goat breed haddifferent genotypes A/A, B/C, C/C and DD. Our results revealed thatthe CSN1S1 allelic variants in tested breed showed differentgenotypes, three of them were homozygous 12.5%, 60.5% and 12.8%respectively for A/A, C/C and D/D and the other was heterozygousB/C (14.2%). Identification of different variants of the casein alpha-S1 can be used to improve milk quality of local goat breed.