Novel single nucleotide polymorphisms and haplotypes within the bovine CXCR2 gene

The objectives of this study were to identify single nucleotide polymorphisms (SNPs) and resulting haplotypes in the bovine CXCR2 gene. A 311-bp segment of the bovine CXCR2 gene was amplified and sequenced. Five SNPs at positions 612, 684, 777, 858, and 861 were expressed in both Holstein and Jersey dairy cattle. Four SNPs resulted in synonymous substitutions, while a non-synonymous switch at position 777 (G-->C) resulted in a glutamine to histidine substitution at amino acid residue 245. Strong linkage disequilibrium was exhibited for both breeds among all five loci (P<0.001). Both allele and genotype frequencies differed significantly with respect to breed at four of the five loci (P<0.001). The five polymorphisms generated ten distinct haplotypes. Six haplotypes were common between the two breeds, while Holsteins and Jerseys each uniquely expressed two haplotypes. Of the six common haplotypes, two represented 83% of the Jersey population; whereas four of these haplotypes represented 95% of the Holstein population.