Genotyping bovine milk proteins using allele discrimination by primer length and automated DNA sizing technology

A method for genotyping K-casein ( A, B, E ), β-casein ( A ¹, A ², A ³, A⁵, B ) and β-lactoglobulin ( A, B ) simultaneously by the use of allele discrimination by primer length combined with automated detection of fragments with a sequencing instrument is described. Seven different mutations within the milk protein genes were analysed in order to distinguish between the alleles examined. The samples were amplified in two separate multiplex polymerase chain reactions (PCRs), which were then pooled and separated according to size in a single lane on the gel. By using stringent PCR conditions, we have been able to achieve allele-specific amplifications and minimize amplification of mismatched primer for all seven mutations.