The tuberous sclerosis 2 (TSC2) and polycystic kidney disease 1 (PKD1) genes are adjacent on human chromosome 16p13.3 and form part of a conserved synteny group with mouse chromosome 17. We have determined that the PKD1 gene is evolutionarily conserved, single copy, and linked to TSC2 in the Fugu genome. A short cosmid contig has been identified containing both genes based on hybridization, exon trapping, and random sequence data. In addition sequences homologous to the somatostatin type V receptor (SSTR5) were identified 5' to PKD1, defining a larger syntenic region, as this gene has also been mapped to human chromosome 16p13.3. As in mammalian genomes, the Fugu TSC2 and PKD1 genes are adjacent in a tail-to-tail orientation.