Novel SNPs of the ABCG2 Gene and Their Associations with Milk Production Traits in Iranian Holstein Bulls

Abstract

ABCG2 (ATP binding cassette subfamily G member 2) gene, located on chromosome 6 encodes the ABCG2 protein that transports various xenobiotics, cytos tatic drugs across the plasma membrane as well as cholesterol into mil k. A single nucleotide change (A/C) in base 86 of exon 14 is capable of encoding a substit ution of tyrosine with serine in the ABCG2 gene and increase milk yield while decreasing milk fat and protein concentrations. The major aim followed in this rese arch was to study Single Nucleotide Polymorphisms (SNPs) of ABCG2 gene and their association with milk production tr aits in Iranian Holstein bulls. Genomic DNA of 105 ified bulls was extracted from semen samples using highly Pure PCR template preparation kit. Primers were designed through Oligo software (Version 5.0) and utilized in PCR. T hen the PCR fragments were sequenced. The A/C substitution in base number 86 of exon 14 was obser ved with 2% frequency which affected protein percentage (P< 0.0 5). Some SNPs were detected for the first time in intron 13, exon and intron 14 in comp arison with sequences in the NCBI database. A deletion mutation in base number 20 (T/ -) and a missense mutation in base number 67 (A/G) of exon 14 that cause the substitut ion of serine with glycine were discovered which were significantly associated with protein yield and fat percentage, respectively (P< 0.05). Furthermore, significant as sociation was observed between fat percentage and mutations in base numbers 4,133 (T/C ) and 4,137 (T/G) of intron 13 (P< 0.05). Substitutions in base numbers 2 (T/C) and 55 (G/C) of intron 14 resulted in a significant effect on fat yield and fat percentage (P< 0.05). Keywords: ABCG2 gene, Holstein bulls , Milk production traits, Polymorphism.