A phylogenetic analysis of β-defensin genes among humans, cattle, and pigs. 36 β-defensin genes from humans, 48 from cattle, and 29 from pigs were analyzed using the neighbor-Joining method. The bootstrap consensus tree inferred from 1,000 replicates and branches corresponding to less than 50 % bootstrap replicates were collapsed. The analysis involved 113 amino acid sequences of β-defensin prepropeptides. pBD, β-defensins; BBD, bovine β-defensins; DEFB, human β-defensins. The “ψ” symbol of pBD117ψ and -127ψ indicates Pseudogenes or partial genes. Sequences of human and cattle β-defensin genes  were obtained from NCBI.