Phylogenetic analyses of fish and human chemokines. Since a large number of chemokines were analyzed, trees were separately constructed with two groups of chemokines (A and B) using the Dayhoff matrix and the neighborjoining method. Four subfamilies of zebrafish chemokines and other species chemokines are indicated by colors and symbols. The zebrafish chemokine genes used in the RT-PCR analyses (Figure 5) are shown in red letters, and the genes identical or similar to those identified by DeVries et al.  and Peatman and Liu  are shown by asterisks (see also Additional file 2). European river lamprey (Lampetra fluviatilis, jawless fish) CXC chemokine LFCA-1 and shark (Triakis scyllium, elasmobranch fish) CC chemokine SCYA107 were also included. Numbers at branch nodes represent the confidence of interior-branch test with 1000 iterations. Only confidence values of ≥50% are shown. The nodes of large branches are unreliable in most cases due to the low values. Amino acid sequences of zebrafish and pufferfish chemokines are shown in Additional file 3. Abbreviations: z, zebrafish; fr, fugu; tn, Tetraodon; h, human; ip, channel catfish; om, rainbow trout; lf, European river lamprey; ts, shark.