PHYSICAL MAPPING OF THE HUMAN HPRT CHROMOSOMAL REGION (XQ26)

The human hprt chromosomal region (Xq26) was physical-mapped using pul sed field gel electrophoresis (PFGE). This work involved: (i) the reco very of three new genomic DNA markers (DXS1327, DXS1328, and DXS1329), (ii) the ordering of new markers relative to 11 previously available hprt-linked markers by deletion mapping, and (iii) the completion of h uman T-lymphocyte PFGE Southern blots using the 14 Xq26 markers. A con tiguous 1.5-Mb physical map of the region telomeric to hprt was determ ined. As this map identifies clusters of in vivo unmethylated rare-cut ter restriction sites, potential CpG islands are revealed.