The murine polycomb-group genes Ezh1 and Ezh2 map close to Hox gene clusters on mouse Chromosomes 11 and 6 Accession numbers. The genomic Ezh1 (accession number AF104360) and genomic Ezh2 (accession number AF104359) sequences have been deposited in GenBank. The fine mapping data of the murine Ezh1 and Ezh2 loci presented in this study have been submitted to MGD and can be accessed under accession number J:50304.-->