Genomic organization of two class II cytokine gene clusters. Chromosomes are shown as lines with the positions of the region marked in megabase pairs underneath. Genes transcribed on the top strand are shown above the line, and those transcribed in the opposite direction are shown below. Class II cytokine encoding genes are shaded in gray. In the left diagram the syntenic regions and duplications, and inversions surrounding the IL-10 locus are shaded in red and blue. The human IL-10 gene is located on chromosome 1 and the region shows the same arrangement as in the mouse. The current zebrafish genome assembly Zv7 does not yet contain the recently sequenced clone CU459075, which places IL-34 into the interval between IL-10 and prolargin (IL-34 is included in Zv7 on the unplaced contig Zv7_NA1656). There are therefore no coordinates for the right end of the interval. The two pufferfish show the same arrangement both for the region around IL-10 and for the MDM1/cytokine/IFN-γ region. The names for the fish genes are explained in the text. IFN, interferon; IL, interleukin.