Supplemental Material and Methods

Quantitative RT-PCR analysis. The following primers were used to amplify β-casein cDNA and 18S rRNA sequences: forward primer of the β-casein gene 5'-GCT CAG GCT CAA ACC ATC TC-3' and reverse primer 5'-TGT GGA AGG AAG GGT GCT AC-3'; forward primer of the 18S rRNA gene 5’-TCGGAACTGAGGCCATGATT-3’ and reverse primer 5’CCTCCGACTTTCGTTCTTGATT-3’. Fragments of β-casein gene and 18S rRNA were amplified with following protocol: 95°C for 10 min (initial denaturation), and 45 amplification cycles (95°C for 5 s, 60°C for 10 s, 72°C for 5 s). Melting curve was analyzed to verify the presence of a single PCR product. GAPDH gene was amplified as described elsewhere (Xu et al, 2007)