(a) Alignment and (b) phylogenetic tree of human and baboon β-defensin protein sequences. The tree was rooted with chicken gallinacin 1 (GGGAL1; P46156) and the reliability of each branch was assessed using 1,000 bootstrap replications. The alignment shows the same sequences with the estimated locations of the signal peptide and mature peptide regions; the intervening region is the propiece. The long arrow indicates the position of first introns: in each case except DEFB105 the intron splits the codon that encodes the residue immediately before the arrow. The short arrow indicates the second intron, found only in DEFB105. The shading represents the degree of conservation at each position in the alignment, taking into account similar physicochemical properties of residues. The six canonical cysteines are indicated under the appropriate alignment positions. X at residue 14 denotes the location of the premature stop codon in DEFB109p.