Populationwide Investigation of Two Indel Polymorphisms at the Prion Protein Gene in Polish Holstein–Friesian Cattle

Abstract

The allele, genotype, and haplotype frequencies among 837 Polish Holstein-Friesian cattle were determined at two regulatory indel polymorphisms of the PRNP gene. Allele frequencies at the 23 bp indel promoter polymorphism were 0.622 (del) and 0.378 (ins), with 0.613 and 0.387 in sires and 0.633 and 0.366 in dams. Allele frequencies at the 12 bp indel intron polymorphism were 0.527 (del) and 0.473 (ins), with 0.529 and 0.471 in sires and 0.543 and 0.456 in dams. Four haplotypes were identified in this population (23-12del, 23-12ins, 23del-12ins, and 23ins-12del). Haplotype 23-12del occurred most frequently in both sire and dam groups. Comparative analysis of Polish Holstein-Friesian and German Holstein populations revealed a similar genetic structure for the 23 bp indel polymorphism and a significantly different one for the 12 bp indel polymorphism. In allele and haplotype analysis, significant differences were observed between the Polish Holstein-Friesian population and a BSE-free German Holstein population.

Abnormal Segregation of Alleles and Haplotypes at the Polymorphic Site of the PRNP Gene Within Promoter and Intron 1 Regions in Polish Holstein–Friesian Cattle

“…Genotype and allele distribution patterns highly similar to those we found have been observed by others in Holstein–Friesian cattle in Poland and other European countries (Juling et al 2006; Haase et al 2007; Czarnik et al 2011). Therefore, it seems that our findings regarding allele and haplotype segregation in Polish Holstein–Friesian cattle can be extrapolated to other European populations of Holstein–Friesians.…”

“…Amplification reactions within polymorphic sites that contained a 23 bp indel in the promoter and a 12 bp indel in intron 1 were carried out by the PCR method, as described by Czarnik et al (2011). The conformity between the observed and anticipated numbers of offspring produced by different genetic variants (23indel and 12indel) of the mated parent pairs was verified by the chi-square test.…”

“…Investigations of the genetic structure conditioned by the indel polymorphism within the 23 bp promoter sequence and the 12 bp intron 1 sequence suggest a higher number of del/del homozygous individuals than ins/ins homozygotes in Holstein–Friesian cattle populations (Juling et al 2006; Nakamitsu et al 2006; Haase et al 2007; Brunelle et al 2008; Czarnik et al 2011). Within the promoter sequence (23del), the share of del/del animals in the population ranges from 31% in the United States to 62.4% in Japan, whereas the share of ins/ins homozygotes ranges from only 5% in Japan to 18% in the United States.…”

“…The genotype frequency of Polish Holstein–Friesian cattle is characteristic of the breed. At the polymorphic site within the promoter region, del/del animals account for 37% of the population and ins/ins individuals for 12.6%, whereas at the polymorphic site within the intron 1 region, del/del animals make up 25.9% and ins/ins homozygotes 20.6% of the population (Czarnik et al 2011). This may indicate the presence of unknown factors that inhibit the distribution of the insertion allele, which determines a lower level of PRNP gene expression in animals with the 23ins-12ins haplotype.…”

Polymorphisms in the Prion Protein Gene of cattle breeds from Brazil

“…Bovines from Turkey have a high frequency of the heterozygous 23-bp genotype and the 12-bp insertion genotype (Un et al 2008). The heterozygous genotypes for 23-bp and 12-bp were the most frequent in a study with Holstein--Friesian bovines from Poland (Czarnik et al 2011). Thus, 23-bp alterations in the promoter region of the gene and 12-bp alterations in intron 1 may be important, as these are considered regulatory sites responsible for the negative feedback of the expression of the prion protein in cattle (Xue et al 2012a(Xue et al , 2012b.…”