Molecular Cloning and Phylogenetic Analysis of Canine β-Casein

A canine β-casein cDNA was isolated from mammary tissue by polymerase chain reaction (PCR) using degenerate primers. It encodes 250 amino acids protein containing the conserved sequence motif of β-casein. It showed the highest homology with snow-leopard (Uncia uncia) (55–62 % identity). It also showed 44–5396 identity with human, 3342 % identity with mouse, 29–37 % identity with rat, 43–53 % identity with rabbit, 4148 % identity with pig, 44–51 % identity with cattle and 44–50 % identity with sheep. A 1.2-kb mRNA was detected in mammary tissue by Northern blot analysis. Phylogenetic analysis revealed that canine β-casein formed a branch with lesser panda and snow leopard, which were grouped into carnivore.