Schematic genomic organization of the zebrafish chemokine gene family. Arrowheads indicate chemokine genes and their transcriptional orientation, and four subfamilies of zebrafish chemokines and other species chemokines are colored as in Figure 2. The numbers under the chemokine genes indicate the numbers of coding exons. The alphabetical letters under the exon numbers show: G, genes predicted only from genomic data; C and E, cDNA clones or EST data available for the genes. Arrows above chromosome 25 show direct or inverted repeats. Dashed lines denote spaces of more than 100 kb.