Physical maps have been constructed around loci DNF15S2, D3S2, and c-raf1 on the short arm of human chromosome 3 using pulsed field gradient gel electrophoresis. The normal restriction pattern has not been altered by a t(3;8)(p14.2;q24.1) characteristic for a hereditary form of renal cell carcinoma, indicating that the breakpoint itself is not included in any of the mapped areas. We have found a CpG island within the DNF15S2 locus, suggesting the presence of a functional gene in the region.