Association of αs1-Casein Gene Polymorphism with Milk Yield and its Composition in Awassi Sheep

Hasan Emad Almasri (1), Abdul Rahman Al-Darwish (1)and  Hiba Albadee

*(1)of Animal Production, Faculty of Agriculture, University of Aleppo.

(* Corresponding auther:Hiba Albadee. E-mail:

  Received: 02/06/2020                                Accepted:28/07/2020


The genetic polymorphism of the milk proteins is of great interest in animal production, because of its influence on milk composition and quality and on the productivity parameters. αs1-casein represents the main milk protein and has an important role in the transport of calcium phosphate. Identification of different αs1-CN gene polymorphism in exon3 traits and its association with different milk performance was performed through Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) of one hundred blood samples using restriction endonuclease Mbo II. Also, Chi-square (χ2) test was performed to test the goodness of fit to Hardy-Weinberg equilibrium (HWE) expectations for the distribution of αs1-CN genotypes in local Awassi sheep, in Minyan, west of Aleppo, during the period 2017-2018. Two alleles (A and C) were found with higher frequency of C allele, whilethree genotypes (AA, AC and CC) were identified at αs1-CN locus. A significant deviation from Hardy-Weinberg equilibrium was found (P<0.05). On the other hand, the results of the statistical analysis, showed significant effects of αs1-CN genotype on milk yield and protein % (P<0.01), while it did not effect on the other milk composition (P>0.05). The results suggest the possibility of a future selection process to improve milk quality in Awassi sheep. Thus the αs1-CN genotype information could be utilized in selection strategies, in order to select genetic stock for the higher milk yield as well as production of sheep milk with higher protein content in marker assisted selection to increase the rate of genetic gain.

Key words: αs1-CN polymorphism, milk proteins,  PCR- RFLP, Awassi sheep.

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