HIGH-RESOLUTION PHYSICAL MAP OF THE X-LINKED RETINOSCHISIS INTERVAL IN XP22

X-linked retinoschisis (RS) is the leading cause of macular degenerati on in young males and has been mapped to Xp22 between DXS418 and DXS99 9. To facilitate identification of the RS gene, we have constructed a yeast artificial chromosome (YAC) contig across this region comprising 28 YACs and 32 sequence-tagged sites including seven novel end clone markers. To establish the definitive marker order, a PAC contig contai ning 50 clones was also constructed, and all clones were fingerprinted , The marker order is: -SP6-DXS418-DXS7994-DXS7995-DXS7996-HYAT2-25HA1 0R- HYAT1-DXS7997-DXS7998-DXS257-434E8R-3542R- DXS6762-DXS7999-DXS6763 -434E8L-DXS8000-DXS6760 -DXS7176-DXS8001-DXS999-3176R-PHKA2-Xcen. A lo ng-range restriction map was constructed, and the RS region is estimat ed to be 1300 kb, containing three putative CpG islands, An unstable r egion was identified between DXS6763 and 434E8L. These data will facil itate positional cloning of RS and other disease genes in Xp22. (C) 19 97 Academic Press.