A new variant in exon VII of bovine beta-casein gene (CSN2) and its distribution among European cattle breeds

An undescribed bovine CSN2 variant was detected and characterized. It is based on a mutation in exon VII, which leads to a substitution of the aminoacid 93 (Met→Leu) in comparison to allele CSN*A2. The new allele was named CSN2*I. A PCR-SSCP based DNA-test for the differentiation of the common alleles A1, A2, A3, B, C, and of the new variant I was developed. Genotyping of 318 unrelated animals belonging to seven European breeds (Italian Holstein Friesian, Italian Red Pied, Piemontese, Angler, Maremmana, Polish Red and White, Polish Red) showed a wide distribution of the new variant with a frequency up to 0.14 in Italian Red Pied.