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Genetic variations of β- and K-casein genes in Egyptian sheep breeds
Abstract
Methodology and results: SSCP of β-casein exon 7 revealed two different patterns in eighty-five tested animals. The sequence analysis of the PCR product (299-bp) of these two different patterns showed two single nucleotide substitutions; A®C and C®T without any amino acid exchange. The frequencies of these two different patterns were 96.67% and 3.33% in Rahmani; 65.52% and 34.48% in Ossimi and 88.46% and 11.54% in Barki, respectively. The nucleotide sequence of 9-casein in Egyptian sheep was submitted in database NCBI/ GenBank with the accession number JX080379. The polymorphism of Kcasein gene was also detected in eighty-six animals using PCR-SSCP technique. PCR amplified a
fragment with 406-bp in exon 4 of this gene. SSCP results showed that all tested sheep animals are monomorphic. The alignment between our sequences with published sequence revealed two nucleotide substitutions; C®T and T®C. The nucleotide sequence of K-casein in our tested animals was submitted in database NCBI/ GenBank with the accession number JX050176.
Conclusion and application of findings: This study aimed to identify the genetic polymorphism of β and Kcasein genes, which are strongly related to economically important milk quantitative traits in some Egyptian sheep breeds, as a tool or genetic markers for improvement of these breeds.
Key words: Sheep, β-casein, K-casein, PCR-SSCP, SNP.