Hitch-hiking from HRAS1 to the WAGR locus with CMGT markers

The clinical association of Wilms' tumour with aniridia, genitourinary abnormalities and mental retardation (WAGR syndrome) is characterised cytogenetically by variable length, constitutional deletion of the short arm of chromosome 11, which always includes at least part of band 11p13. HRAS1-selected chromosome mediated gene transfer (CMGT) generated a transformant, E65-6, in which the only human genes retained map either to band 11p13 or, with HRAS1, in the region 11p15.4-pter. Human recombinants isolated from E65-6 were mapped to a panel of five WAGR deletion hybrids and two clinically related translocations. We show that E65-6 is enriched congruent to 400-fold for 11p15.4-pter markers and congruent to 200-fold for 11p13 markers. 'Hitch-hiking' from HRAS1 with CMGT markers has allowed us to define seven discrete intervals which subtend band 11p13. Both associated translocations co-locate within the smallest region of overlap for the WAGR locus, which has been redefined by identifying a new interval closer than FSHB.