Genetic polymorphism of whey protein genes β-LG and α-LA in three Egyptian sheep breeds

The major whey proteins,β-lactoglobulin (β-lg) and α-lactalbumin (α-la),are strongly correlated with the nutritional value and the functional properties of milk whey. ovine whey has a unique protein composition compared to that of bovine whey and it is especially rich in proteins. genetic polymorphism of β-lg using pcr-rflp and α-la using pcr-sscp was analyzed in three native egyptian sheep breeds named barki,rahmani and ossimi. digestion of resulting amplified fragments of β-lg (452-bp) with rsai endonuclease differentiated between three different genotypes aa (69.77%),ab (26.74%) and bb (3.49%). the results showed that a allele was present in the egyptian sheep breeds with a frequency (83.14%) higher than b allele (16.86%). a & b alleles appeared at frequencies 70.4 % & 29.6%,95.0% & 5.0% and 82.8% & 17.2% in barki,rahmani and ossimi,respectively sscp results of the α-la amplified fragments (166-bp) showed that the three native egyptian sheep breeds possess two different patterns related to the difference in nucleotide sequences with frequencies 88.1% and 11.9%. the frequencies of pattern 1 ranged from 81.48% in barki to 89.66% in ossimi and 92.86% in rahmani breeds whereas the pattern 2 was present at frequencies 18.52%,7.14% and 10.34% in barki,rahmani and ossimi breeds,respectively.