Relationship between the insertion/deletion polymorphism within the promoter and the intron 1 sequence of the PRNP gene and milk performance traits in cattle
J. Strychalski, U. Czarnik, M. Pierzchała, C.S. Pareekhttps://doi.org/10.17221/1436-CJASCitation:Strychalski J., Czarnik U., Pierzchała M., Pareek C.S. (2011): Relationship between the insertion/deletion polymorphism within the promoter and the intron 1 sequence of the PRNP gene and milk performance traits in cattle. Czech J. Anim. Sci., 56: 151-156.
Current studies on the prion protein (PRNP) gene polymorphism focus primarily on the causative mutations that influence BSE susceptibility in cattle. The specific genetic structure determined by the insertion/deletion (indel) polymorphism within the 23 bp promoter sequence and the 12 bp intron 1 sequence of the PRNP gene, and its genomic location suggest that this polymorphism can be a potential QTL marker. The objective of the present study was to determine whether the indel polymorphism within the promoter sequence (23 bp) and the intron 1 sequence (12 bp) of the PRNP gene can be used as a factor differentiating the values of milk performance traits. The experimental materials comprised 285 primiparous Polish Holstein-Friesian cows, daughters of two dihybrid (23ins-12ins/23del-12del) sires (progeny of sire 1 – 149 cows, progeny of sire 2 – 136 cows). The following milk performance traits were analysed: milk yield, milk fat yield, milk protein yield, fat and protein contents of milk during the first 305-day lactation. The polymorphism in the promoter region (23 bp) was found to have a significant (P = 0.040) effect on protein yield and a highly significant (P = 0.007) effect on the protein content of milk. The highest values of these traits were noted in 23 ins/del heterozygotes and the lowest in 23 del/del homozygotes. There was an interrelation between diplotype variants and the concentrations of milk components. The protein content of milk was highly significantly (P = 0.007) higher in 23ins-12ins/23del-12del heterozygotes and significantly (P = 0.028) higher in 23ins-12ins/23ins-12ins homozygotes, compared to 23del-12ins/23del-12del cows. 23ins-12ins/23del-12del heterozygotes were also characterized by a significantly (P = 0.046) higher fat content of milk, in comparison with 23del-12del/23del-12del homozygotes.Keywords:
Polish Holstein-Friesian cattle; PRNP polymorphism; milk performance traits; QTL marker