Physical Mapping in a YAC Contig of 11 Markers on the Human X Chromosome in Xp11.23

By using yeast artificial chromosome (YAC) clones, we have generated a physical map of the short arm of the human X chromosome at Xp11.23. The region analyzed spans the distal marker UBE1 and the ARAF1/TIMP/SYN1/PFC gene cluster and further extends proximally to include ELK1, ZNF21, ZNF81, and OATL1 in a single contig. We have uniquely placed UBE1 and the SYN1 gene cluster in a 330-kb YAC within the contig. In addition, the genes SYP and TFE3 are physically linked in a YAC of 400 kb from the more centromeric portion of Xp11.23. We have refined the map by using fragmentation vectors to generate YAC deletion derivatives. These derivatives show that ZNF81 and ZNF21 lie within an approximately 130-kb segment and that SYN1.2 and ELK1 are less than 50 kb apart. Together these data reveal the following order for the markers in this region: Xpter-UBE1-ARAF1-TIMP-SYN1.2-PFC-ELK1-ZNF81-ZNF21-OATL1-(SYP,TFE3)-Xcen.