Water buffalo kappa-casein gene sequence

The aim of the present work was to determine the nucleotide sequence of the water buffalo CSN3 gene (κ-casein). Two overlapping clones from a genomic water buffalo library were sequenced. The sequence comprises the five exons, the relative introns, 1057 nt at the 5’ end of the gene and 476 nt downstream the polyadenylation site. In order to identify polymorphisms responsible for amino acid differences, all the five exons from 10 genetically unrelated water buffaloes were sequenced. The comparison of the obtained sequences confirmed the two single nucleotide polymorphisms already reported in literature at the fourth exon: T versus C at codon 135 (IleATC versus ThrACC) and the silent mutation T versus C at codon 136. The comparison of the promoter sequences of two animals homozygous for 135Thr and 135Ile respectively, evidenced 3 single nucleotide polymorphisms that could alter the expression of the gene.